HomeMy WebLinkAboutMCG McGrath K12 School 2012-EEManaging Office
2400 College Road 3105 Lakeshore Dr. Suite 106A 4402 Thane Road
Fairbanks, Alaska 99709 Anchorage, Alaska 99517 Juneau, Alaska 99801
p. 907.452.5688 p. 907.222.2445 p: 907.586.6813
f. 907.452.5694 f. 907.222.0915 f: 907.586.6819
www.nortechengr.com
ENERGY AUDIT – FINAL REPORT
MCGRATH SCHOOL
90 Chinana Ave
McGrath, Alaska
Prepared for:
Mr. Steve Graham
Director of Maintenance and Facilities
Iditarod Area School District
P.O. Box 90
McGrath, AK 99627
Prepared by:
David C. Lanning PE, CEA
Jason Ginter CEA
Pauline E. Fusco EIT, CEAIT
July 12, 2012
Acknowledgment: "This material is based upon work supported by the Department of
Energy under Award Number DE-EE0000095.”
ENVIRONMENTAL ENGINEERING, HEALTH & SAFETY
Anch: 3105 Lakeshore Dr. Ste 106A, 99517 907.222.2445 Fax: 222.0915
Fairbanks: 2400 College Road, 99709 907.452.5688 Fax: 452.5694
Juneau: 4402 Thane Road, 99801 907.586.6813 Fax: 586.6819
info@nortechengr.com www.nortechengr.com
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
i
TABLE OF CONTENTS
1.0 EXECUTIVE SUMMARY .................................................................................................. 1
2.0 INTRODUCTION ............................................................................................................... 4
2.1 Building Use .......................................................................................................... 4
2.2 Building Occupancy and Schedules ...................................................................... 4
2.3 Building Description ............................................................................................... 4
3.0 BENCHMARKING 2011 UTILITY DATA .......................................................................... 7
3.1 Total Energy Use and Cost in 2011 ...................................................................... 8
3.2 Energy Utilization Index for 2011 .......................................................................... 9
3.3 Cost Utilization Index for 2011 ............................................................................ 10
3.4 Seasonal Energy Use Patterns ........................................................................... 11
3.5 Future Energy Monitoring .................................................................................... 12
4.0 MODELING ENERGY CONSUMPTION ......................................................................... 13
4.1 Understanding How AkWarm Models Energy Consumption ............................... 14
4.2 AkWarm Calculated Savings for the McGrath School ......................................... 15
4.3 Additional Modeling Methods .............................................................................. 16
5.0 BUILDING OPERATION AND MAINTENANCE (O & M) .............................................. 17
5.1 Operations and Maintenance .............................................................................. 17
5.2 Commissioning .................................................................................................... 17
5.3 Building Specific Recommendations ................................................................... 17
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
ii
APPENDICES
Appendix A Recommended Energy Efficiency Measures ........................................... 20
Appendix B Energy Efficiency Measures that are NOT Recommended ..................... 26
Appendix C Significant Equipment List ....................................................................... 27
Appendix D Local Utility Rate Structure ...................................................................... 28
Appendix E Analysis Methodology .............................................................................. 29
Appendix F Audit Limitations ...................................................................................... 30
Appendix G References .............................................................................................. 31
Appendix H Typical Energy Use and Cost – Fairbanks and Anchorage ..................... 32
Appendix I Typical Energy Use and Cost – Continental U.S. .................................... 33
Appendix J List of Conversion Factors and Energy Units .......................................... 34
Appendix K List of Acronyms, Abbreviations, and Definitions .................................... 35
Appendix L Building Floor Plan .................................................................................. 36
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
1
1.0 EXECUTIVE SUMMARY
NORTECH has completed an ASHRAE Level II Energy Audit of the McGrath School, a 38,100
square foot facility in the Iditarod Area School District. The audit began with benchmarking
which resulted in a calculation of the energy consumption per square foot. A site inspection was
completed March 7th to March 9th, 2012 to obtain information about the lighting, heating,
ventilation, cooling and other building energy uses. The existing usage data and current
systems were then used to develop a building energy consumption model using AkWarm.
Once the model was calibrated, a number of Energy Efficiency Measures (EEMs) were
developed from review of the data and observations. EEMs were evaluated and ranked on the
basis of both energy savings and cost using a Savings/Investment Ratio (SIR). While these
modeling techniques were successful in verifying that many of the EEMs would save energy,
not all of the identified EEMs were considered cost effective based on the hardware, installation,
and energy costs at the time of this audit.
While the need for a major retrofit can typically be identified by an energy audit, upgrading
specific systems often requires collecting additional data and engineering and design efforts that
are beyond the scope of the Level II energy audit. The necessity and amount of design effort
and cost will vary depending on the scope of the specific EEMs planned and the sophistication
and capability of the entire design team, including the building owners and operators. During
the budgeting process for any major retrofit identified in this report, the building owner should
add administrative and supplemental design costs to cover the individual needs of their own
organization and the overall retrofit project.
The recommended EEMs for the Building Name are summarized in the table below. Additional
discussion of the modeling process can be found in Section 3. Details of each individual EEM
can be found in Appendix A of this report. A summary of EEMs that were evaluated but are not
currently recommended is located in Appendix B.
PRIORITY LIST – ENERGY EFFICIENCY MEASURES (EEMs)
Rank Feature/
Location Improvement Description
Estimated
Annual
Energy
Savings
Estimated
Installed
Cost
Savings to
Investment
Ratio, SIR
Simple
Payback
(Years)
1 Refrigeration
Shut down the walk-in freezer and
refrigerator and use Energy Star full
size upright refrigerators and chest
freezers instead. Remove the
compact refrigerator and any
unused refrigeration.
$10,790 $6,150 11.0 0.6
2 HVAC And
DHW
Replace (3) primary circulation
pumps and (1) DHW circulation
pump with Grundfos Alpha or
Magna pumps or equivalent.
Install a timer on the DHW pump
so that the pump operates only
during occupied hours.
$6,534 $22,000 2.4 3.4
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
2
PRIORITY LIST – ENERGY EFFICIENCY MEASURES (EEMs)
Rank Feature/
Location Improvement Description
Estimated
Annual
Energy
Savings
Estimated
Installed
Cost
Savings to
Investment
Ratio, SIR
Simple
Payback
(Years)
3 Setbacks
Install programmable thermostats in
classrooms, library, gym, locker
rooms and hallways and implement
a night-time and unoccupied
setback to 60°F.
Control and reduce the crawlspace
temperature to 55°F.
Reduce the warehouse temperature
during night-time and unoccupied
periods to 50°F.
$21,937 $60,400 2.4 2.8
4 Lighting Replace T8 fluorescent lamps with
17W LED lamps. $10,339 $148,560 1.0 14
TOTAL, cost-effective measures $49,600 $237,110 1.9 4.8
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
3
Modeled Building Energy Cost Breakdown
The above charts are a graphical representation of the modeled energy usage for the McGrath
School. The greatest portions of energy cost for the building are envelope air losses, lighting,
and floor heat loss. Detailed improvements can be found in Appendix A.
The energy cost by end use breakdown was provided by AkWarm based on the field inspection
and does not indicate that all individual fixtures and appliances were directly measured. The
current energy costs are shown above on the left hand pie graph and the projected energy
costs, assuming use of the recommended EEMs, are shown on the right.
The chart breaks down energy usage by cost into the following categories:
Envelope Air Losses—the cost to provide heated fresh air to occupants, air leakage, heat lost in
air through the chimneys and exhaust fans, heat lost to wind and other similar losses.
Envelope
o Ceiling—quantified heat loss transferred through the ceiling portion of the envelope.
o Window—quantified heat loss through the window portion of the envelope.
o Wall/Door—quantified heat loss through the wall and door portions of the envelope.
o Floor—quantified heat loss through the floor portion of the envelope.
Water Heating—energy cost to provide domestic hot water.
Fans—energy cost to run ventilation, and exhaust fans.
Lighting—energy cost to light the building.
Refrigeration—energy costs to provide refrigerated goods for the occupants.
Other Electrical—includes energy costs not listed above including cooking loads, laundry loads,
other plug loads and electronics.
Envelope
Air Losses
$35,219
22%
Ceiling
$16,603
11%
Window
$5,534
4%
Wall/Door
$16,100
10%
Floor
$27,672
18%
Water
Heating
$4,450
3%
Fans
$45
0%
Lighting
$28,696
18%
Refriger-
ation
$19,582
12%
Other
Electrical
$3,336
2%
Existing Building Energy Cost
$156,482
Envelope
Air Losses
$28,158
18%
Ceiling
$14,079
9%
Window
$3,520
2%
Wall/Door
$12,570
8%
Floor
$22,627
14%Water
Heating
$4,377
3%
Fans
$45
0%
Lighting
$14,852
10%
Refriger-
ation
$3,328
2%
Other
Electrical
$3,336
2%
Temper-
ature
Setback
Savings
$21,937
14%
Refriger-
ation
Savings
$10,790
7%
Lighting
Savings
$10,339
7%
HVAC
Savings
$6,534
4%
Retrofit Building Energy Cost
$106,883
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
4
2.0 INTRODUCTION
NORTECH contracted with The Alaska Housing Finance Corporation to perform ASHRAE
Level II Energy Audits for publically owned buildings in Alaska. This report presents the findings
of the utility benchmarking, modeling analysis, and the recommended building modifications,
and building use changes that are expected to save energy and money.
The report is organized into sections covering:
description of the facility,
the building’s historic energy usage (benchmarking),
estimating energy use through energy use modeling,
evaluation of potential energy efficiency or efficiency improvements, and
recommendations for energy efficiency with estimates of the costs and savings.
2.1 Building Use
The McGrath School provides educational services to kindergarten through 12th grade students
in McGrath, Alaska. The adjacent warehouse serves as a bus barn, storage facility and
maintenance shop, and is also included in the AkWarm model.
2.2 Building Occupancy and Schedules
The building is occupied by 40 students, 4 teachers, and 2 other staff members during the
school year, August through May, from approximately 8:00 am to 5:00 pm, weekdays. The gym
is used approximately 40 hours a week, and the building is cleaned about 20 hours a week.
2.3 Building Description
The single-story wood-framed school was constructed in 1964 on an all-weather wood frame
foundation. Several subsequent renovations have added classroom space, replaced the roof,
added a warehouse, and altered the HVAC system.
Building Envelope
Building Envelope: Walls
Wall Type Description Insulation Notes
Main Wood-framed with 2x8 studs
spaced 16-inches on center.
Approximately R-30
fiberglass batt
insulation.
No as-builts available.
Crawlspace Wood-framed with 2x6 studs
spaced 16-inches on center.
Approximately R-30
rigid insulation in stud
bays, and R-30 rigid
insulation installed
horizontally
approximately 2 ft
below grade.
No as-builts available.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
5
Heating and Ventilation Systems
Cogenerated heat (Waste Heat) from the McGrath Light and Power plant, in conjunction with
heat from two oil-fired boilers, is distributed to the three air handlers, cabinet unit heaters,
baseboards, unit heaters, and the indirect Domestic Hot Water (DHW) maker.
The Waste Heat is also piped from the school to the warehouse and the IASD district office.
The building temperatures are controlled by nonprogrammable thermostats typically set to 70-
72° F.
Building Envelope: Floors
Floor Type Description Insulation Notes
Crawlspace Bare earth. None
Install 6-mil
polyethylene vapor
barrier to reduce
moisture intrusion.
Building Envelope: Roof
Roof Type Description Insulation Notes
School Wood framed with deep trusses.
Approximately R-85
fiberglass loose fill plus
R-2 rigid insulation on
exterior.
--
Building Envelope: Doors and Windows
Door and Window
Type Description Estimated
R-Value Notes
All Doors
Metal (full-lite, ¼ -lite or no-lite)
insulated exterior doors with no
thermal break.
R-3.0 to R-5.0
Weather stripping
appears in acceptable
condition.
Garage Door Metal insulated panels. R-5.6 Weather stripping
requires repair.
Windows Double-pane vinyl windows. R-2.2
Appears to be in
excellent condition. A
recent retrofit.
South Vestibule
Windows
Double-pane metal-framed
storefront windows. R-1.2 Less than 5% of
window area.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
6
Ventilation Systems
Three air handlers provide ventilation and some heating to the school.
AHU-1 serves the stage and cafeteria,
AHU-2 serves the crawlspace and does not provide outside air,
AHU-3 serves the remainder of the school, but is currently shut down due to the low
student population.
Air Conditioning System
Economizer cooling is possible with the existing system.
Energy Management
There is no energy management system.
Lighting Systems
All areas are illuminated by ceiling mounted fluorescent fixtures with T8 lamps (1.5 inch
diameter tubes), except for the gym which is lit by fluorescent high bay fixtures with T5 lamps.
Most of the
Domestic Hot Water
DHW is provided by an indirect hot water heater. Hot water is re-circulated 24 hours per day.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
7
3.0 BENCHMARKING 2011 UTILITY DATA
Benchmarking building energy use consists of obtaining and then analyzing two years of energy
bills. The original utility bills are necessary to determine the raw usage, and charges as well as
to evaluate the utility’s rate structure. The metered usage of electrical and natural gas
consumption is measured monthly, but heating oil, propane, wood, and other energy sources
are normally billed upon delivery and provide similar information. During benchmarking,
information is compiled in a way that standardizes the units of energy and creates energy use
and billing rate information statistics for the building on a square foot basis. The objectives of
benchmarking are:
to understand patterns of use,
to understand building operational characteristics,
for comparison with other similar facilities in Alaska and across the country, and
to offer insight in to potential energy savings.
The results of the benchmarking, including the energy use statistics and comparisons to other
areas, are discussed in the following sections.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
8
3.1 Total Energy Use and Cost of 2011
The energy use profiles below show the energy and cost breakdowns for the McGrath School.
The total 2011 energy use for the building was 2,953 mmBTU and the total cost was $162,296.
These charts show the portion of use for a fuel type and the portion of its cost.
The above charts indicate that the highest portion of energy use is for Waste Heat and the
highest portion of cost is for electricity. Waste Heat and fuel oil consumption correlates directly
to space heating and domestic hot water while electrical use can correlate to lighting systems,
plug loads, and HVAC equipment. The energy type with the highest cost often provides the
most opportunity for savings.
Electric
627
21%
Waste
Heat
1,234
42%
Oil
1,091
37%
Energy Use Total
(mmBTU)
Electric
$83,476
51%
Waste
Heat
$30,613
19%
Oil
$48,207
30%
Energy Cost Total ($)
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
9
3.2 Energy Utilization Index of 2011
The primary benchmarking statistic is the Energy Utilization Index (EUI). The EUI is calculated
from the utility bills and provides a snapshot of the quantity of energy actually used by the
building on a square foot and annual basis. The calculation converts the total energy use for
the year from all sources in the building, such as heating fuel and electrical usage, into British
Thermal Units (BTUs). This total annual usage is then divided by the number of square feet of
the building. The EUI units are BTUs per square foot per year.
The benchmark analysis found that the McGrath School has an EUI of 78,000 BTUs per square
foot per year.
The EUI is useful in comparing this building’s energy use to that of other similar buildings in
Alaska and in the Continental United States. The EUI can be compared to average energy use
in 2003 found in a study by the U.S. Energy Information Administration of commercial buildings
(abbreviated CBECS, 2006). That report found an overall average energy use of about 90,000
BTUs per square foot per year while studying about 6,000 commercial buildings of all sizes,
types, and uses that were located all over the Continental U.S. (see Table C3 in Appendix I).
In a recent and unpublished state-wide benchmarking study sponsored by the Alaska Housing
Finance Corporation, schools in Fairbanks averaged 62,000 BTUs per square foot and schools
in Anchorage averaged 123,000 BTUs per square foot annual energy use. The chart below
shows the McGrath School relative to these values. These findings are discussed further in
Appendix H.
78,000
62,000
123,000
0
20000
40000
60000
80000
100000
120000
140000
Btu/ Sq. FtAnnual Energy Use Index (Total Energy/ SF)
McGrath School Fairbanks Schools Anchorage Schools
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
10
3.3 Cost Utilization Index of 2011
Another useful benchmarking statistic is the Cost Utilization Index (CUI), which is the cost for
energy used in the building on a square foot basis per year. The CUI is calculated from the cost
for utilities for a year period. The CUI permits comparison of buildings on total energy cost even
though they may be located in areas with differing energy costs and differing heating and/or
cooling climates. The cost of energy, including heating oil, natural gas, and electricity, can vary
greatly over time and geographic location and can be higher in Alaska than other parts of the
country.
The CUI for McGrath School is about $4.26 per square foot per year. This is based on utility
costs from 2011 and the following rates:
Electricity at $ 0.45 / kWh ($ 13.18 / Therm)
# 1 Fuel Oil at $ 5.92 / gallon ($ 4.42 / Therm)
Waste Heat at $ 24.80/mmBTU ($ 2.48 /Therm)
The Department of Energy Administration study, mentioned in the previous section (CBECS,
2006) found an average cost of $2.52 per square foot in 2003 for 4,400 buildings in the
Continental U.S (Tables C4 and C13 of CBDES, 2006). Schools in Fairbanks have an average
cost for energy of $2.42 per square foot while Anchorage schools average $2.11 per square
foot. The chart below shows the McGrath School relative to these values. More details are
included in Appendix H.
$4.26
$2.42
$2.11
$0.00
$0.50
$1.00
$1.50
$2.00
$2.50
$3.00
$3.50
$4.00
$4.50
$/Sq. FtAnnual Energy Cost Index (Total Cost/ SF)
McGrath School Fairbanks Schools Anchorage Schools
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
11
3.4 Seasonal Energy Use Patterns
Energy consumption is often highly correlated with seasonal climate and usage variations. The
graphs below show the electric and fuel consumption of this building over the course of two
years. The lowest monthly use is called the baseline use. The electric baseline often reflects
year round lighting consumption. The clear relation of increased energy usage during periods of
cold weather can be seen in the months with higher usage.
Fuel oil consumption is based on boiler run time hours recorded by school maintenance personnel and
extrapolated using daily local Heating Degree Days (HDD). Waste heat consumption is estimated using an
energy balance between McGrath School and the IASD District Office. Space heating and DHW heating is the
sum of the two sources.
0
5000
10000
15000
20000
25000
30000
Jan-09Mar-09May-09Jul-09Sep-09Nov-09Jan-10Mar-10May-10Jul-10Sep-10Nov-10Jan-11Mar-11May-11Jul-11Sep-11Nov-11Jan-12KWHElectrical Consumption
McGrath School
0.00
50.00
100.00
150.00
200.00
250.00
Jan-09Mar-09May-09Jul-09Sep-09Nov-09Jan-10Mar-10May-10Jul-10Sep-10Nov-10Jan-11Mar-11May-11Jul-11Sep-11Nov-11Jan-12mmBTUsCogenerated Heat and Estimated Fuel Oil Consumption
McGrath School
Estimated Fuel Oil Consumption Cogenerated Heat
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
12
3.5 Future Energy Monitoring
Energy accounting is the process of tracking energy consumption and costs. It is important for
the building owner or manager to monitor and record both the energy usage and cost each
month. Comparing trends over time can assist in pinpointing major sources of energy usage and
aid in finding effective energy efficiency measures. There are two basic methods of energy
accounting: manual and automatic. Manual tracking of energy usage may already be performed
by an administrative assistant: however if the records are not scrutinized for energy use, then
the data is merely a financial accounting. Digital energy tracking systems can be installed. They
display and record real-time energy usage and accumulated energy use and cost. There are
several types which have all of the information accessible via Ethernet browser.
McGrath School has installed a BTU meter to track waste heat energy consumption.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
13
4.0 MODELING ENERGY CONSUMPTION
After benchmarking of a building is complete and the site visit has identified the specific systems
in the building, a number of different methods are available for quantifying the overall energy
consumption and to model the energy use. These range from relatively simple spreadsheets to
commercially available modeling software capable of handling complex building systems.
NORTECH has used several of these programs and uses the worksheets and software that
best matches the complexity of the building and specific energy use that is being evaluated.
Modeling of an energy efficiency measure (EEM) requires an estimate of the current energy
used by the specific feature, the estimated energy use of the proposed EEM and its installed
cost. EEMs can range from a single simple upgrade, such as light bulb type or type of motor, to
reprogramming of the controls on more complex systems. While the need for a major retrofit
can typically be identified by an energy audit, the specific system upgrades often require
collecting additional data and engineering and design efforts that are beyond the scope of the
Level II energy audit.
Based on the field inspection results and discussions with the building owners/operators,
auditors developed potential EEMs for the facility. Common EEMs that could apply to almost
every older building include:
Reduce the envelope heat losses through:
o increased building insulation, and
o better windows and doors
Reduce temperature difference between inside and outside using setback thermostats
Upgrade inefficient:
o lights,
o motors,
o refrigeration units, and
o other appliances
Reduce running time of lights/appliances through:
o motion sensors,
o on/off timers,
o light sensors, and
o other automatic/programmable systems
The objective of the following sections is to describe how the overall energy use of the building
was modeled and the potential for energy savings. The specific EEMs that provide these overall
energy savings are detailed in Appendix A of this report. While the energy savings of an EEM is
unlikely to change significantly over time, the cost savings of an EEM is highly dependent on the
current energy price and can vary significantly over time. An EEM that is not currently
recommended based on price may be more attractive at a later date or with higher energy
prices.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
14
4.1 Understanding How AkWarm Models Energy Consumption
NORTECH used the AkWarm model for evaluating the overall energy consumption at McGrath
School. The AkWarm program was developed by the Alaska Housing Finance Corporation
(AHFC) to model residential energy use. The original AkWarm is the modeling engine behind
the successful residential energy upgrade program that AHFC has operated for a number of
years. In the past few years, AHFC has developed a version of this model for commercial
buildings.
Energy use in buildings is modeled by calculating energy losses and consumption, such as:
• Heat lost through the building envelope components, including windows, doors,
walls, ceilings, crawlspaces, and foundations. These heat losses are computed for
each component based on the area, heat resistance (R-value), and the difference
between the inside temperature and the outside temperature. AkWarm has a library
of temperature profiles for villages and cities in Alaska.
• Window orientation, such as the fact that south facing windows can add heat in the
winter but north-facing windows do not.
• Inefficiencies of the heating system, including the imperfect conversion of fuel oil or
natural gas due to heat loss in exhaust gases, incomplete combustion, excess air,
etc. Some electricity is also consumed in moving the heat around a building through
pumping.
• Inefficiencies of the cooling system, if one exists, due to various imperfections in a
mechanical system and the required energy to move the heat around.
• Lighting requirements and inefficiencies in the conversion of electricity to light;
ultimately all of the power used for lighting is converted to heat. While the heat may
be useful in the winter, it often isn’t useful in the summer when cooling may be
required to remove the excess heat. Lights are modeled by wattage and operational
hours.
• Use and inefficiencies in refrigeration, compressor cooling, and heat pumps. Some
units are more efficient than others. Electricity is required to move the heat from
inside a compartment to outside it. Again, this is a function of the R-Value and the
temperature difference between the inside and outside of the unit.
• Plug loads such as computers, printers, mini-fridges, microwaves, portable heaters,
monitors, etc. These can be a significant part of the overall electricity consumption
of the building, as well as contributing to heat production.
• The schedule of operation for lights, plug loads, motors, etc. is a critical component
of how much energy is used.
AkWarm adds up these heat losses and the internal heat gains based on individual unit usage
schedules. These estimated heat and electrical usages are compared to actual use on both a
yearly and seasonal basis. If the AkWarm model is within 5 % to 10% of the most recent 12
months usage identified during benchmarking, the model is considered accurate enough to
make predictions of energy savings for possible EEMs.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
15
4.2 AkWarm Calculated Savings for the McGrath School
Based on the field inspection results and discussions with the building owners/operators,
auditors developed potential EEMs for the facility. These EEMs are then entered into AkWarm
to determine if the EEM saves energy and is cost effective (i.e. will pay for itself). AkWarm
calculates the energy and money saved by each EEM and calculates the length of time for the
savings in reduced energy consumption to pay for the installation of the EEM. AkWarm makes
recommendations based on the Savings/Investment Ratio (SIR), which is defined as ratio of the
savings generated over the life of the EEM divided by the installed cost. Higher SIR values are
better and any SIR above one is considered acceptable. If the SIR of an EEM is below one, the
energy savings will not pay for the cost of the EEM and the EEM is not recommended.
Preferred EEMs are listed by AkWarm in order of the highest SIR.
A summary of the savings from the recommended EEMs are listed in this table.
Description Space
Heating
Water
Heating Lighting Refrigeration Other
Electrical Cooking Ventilation
Fans Total
Existing
Building $101,398 $4,448 $28,696 $18,560 $2,358 $978 $45 $156,482
With All
Proposed
Retrofits
$80,953 $4,377 $14,843 $3,328 $2,358 $978 $45 $106,883
Savings $20,445 $71 $13,853 $15,232 $0 $0 $0 $49,600
Savings in these categories represent the overall savings for the building, and reflect any added
cost that might occur because of a retrofit. For example, installing more efficient lights will
increase the heating load and creating or lowering an unoccupied setback temperature will
increase hot water heat losses and cost.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
16
4.3 Additional Modeling Methods
The AkWarm program effectively models wood-framed and other buildings with standard
heating systems and relatively simple HVAC systems. AkWarm models of more complicated
mechanical systems are sometimes poor due to a number of simplifying assumptions and
limited input of some variables. Furthermore, AKWarm is unable to model complex HVAC
systems such as variable frequency motors, variable air volume (VAV) systems, those with
significant digital or pneumatic controls or significant heat recovery capacity. In addition, some
other building methods and occupancies are outside AkWarm capabilities.
This report section is included in order to identify benefits from modifications to those more
complex systems or changes in occupant behavior that cannot be addressed in AkWarm.
In order to benchmark the utility data, it was necessary to allocate waste heat between the
buildings, and use the IASD District Office AkWarm model to check the reasonableness of the
allocations. As a result, the benchmarking data did not allow AkWarm to be calibrated within
NORTECH standards. Therefore, energy savings and cost savings predicted by AkWarm have
a higher than standard range of error.
One mmBTU is 1 million BTUs of heat and is comparable to about 8 gallons of fuel oil.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
17
5.0 BUILDING OPERATION AND MAINTENANCE (O & M)
5.1 Operations and Maintenance
A well-implemented operation and maintenance (O & M) plan is often the driving force behind
energy savings. Such a plan includes preserving institutional knowledge, directing preventative
maintenance, and scheduling regular inspections of each piece of HVAC equipment within the
building. Routine maintenance includes the timely replacement of filters, belts and pulleys, the
proper greasing of bearings and other details such as topping off the glycol tanks. Additional
benefits to a maintenance plan are decreased down time for malfunctioning equipment, early
indications of problems, prevention of exacerbated maintenance issues, and early detection of
overloading/overheating issues. A good maintenance person knows the building’s equipment
well enough to spot and repair minor malfunctions before they become major retrofits.
Operations and Maintenance staff implementing a properly designed O & M plan will:
Track and document
o Renovations and repairs,
o Utility bills and fuel consumption, and
o System performance.
Keep available for reference
o A current Building Operating Plan including an inventory of installed systems,
o The most recent available as-built drawings,
o Reference manuals for all installed parts and systems, and
o An up-to-date inventory of on-hand replacement parts.
Provide training and continuing education for maintenance personnel.
Plan for commissioning and re-commissioning at appropriate intervals.
5.2 Commissioning
Commissioning of a building is the verification that the HVAC systems perform within the design
or usage ranges of the Building Operating Plan. This process ideally, though seldom, occurs as
the last phase in construction. HVAC system operation parameters degrade from ideal over time
due to incorrect maintenance, improper replacement pumps, changes in facility tenants or
usage, changes in schedules, and changes in energy costs or loads. Ideally, re-commissioning
of a building should occur every five to ten years. This ensures that the HVAC system meets
the potentially variable use with the most efficient means.
5.3 Building Specific Recommendations
The school occupancy is far below the design occupancy for the building. Closing off and
reducing the temperature in unused classrooms may be a feasible way to reduce energy
consumption.
Institute monitoring of waste heat distributed to other buildings. The benchmarking of waste
heat consumption for the other buildings should be used to identify additional EEMs or
maintenance concerns. Using existing benchmarking, the IASD Business Office was already
able to identify a maintenance issue that could have increased annual waste heat consumption
in 2011 by approximately 5% if not detected.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
18
The crawlspace is approximately 80°F. Reduce the crawlspace temperature to the design
temperature of 55°F to achieve significant energy savings.
The crawlspace may be overheated as the result of one or more of the following:
Uncontrolled heat loss from glycol heating pipes and air handling ducts,
Faulty thermostats or poorly located thermostats, and
Faulty zone valves.
Solving the overheating issue may require a skilled HVAC technician.
The gym lighting occupancy sensors are inoperable and need to be repaired. If the sensors
were manually bypassed due to dissatisfaction with sensor sensitivity or other aspects of
operation, rectify the issues.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
19
APPENDICES
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
20
Appendix A Recommended Energy Efficiency Measures
A number of Energy Efficiency Measures (EEMs) are available to reduce the energy use and
overall operating cost for the facility. The EEMs listed below are those recommended by
AkWarm based on the calculated savings/investment ration (SIR) as described in Appendix E.
AkWarm also provides a breakeven cost, which is the maximum initial cost of the EEM that will
still return a SIR of one or greater.
This section describes each recommended EEM and identifies the potential energy savings and
installation costs. This also details the calculation of breakeven costs, simple payback, and the
SIR for each recommendation. The recommended EEMs are grouped together generally by the
overall end use that will be impacted.
A.1 Temperature Control
Twenty programmable thermostats should be installed in the school and programmed for a
night-time and unoccupied setback of 60°F in classrooms, hallways, locker rooms, and the gym.
An additional programmable thermostat should be installed in the warehouse and programmed
for an unoccupied setback to 50°F. Programmable thermostats allow for automatic
temperature setback, which reduce usage more reliably than manual setbacks. Instituting a
night-time and unoccupied temperature set back will decrease the amount of energy required to
heat the building.
The crawlspace temperature should be reduced to 55°F for approximately $14,000 per year in
annual savings. This may require simply replacing a thermostat, or a more comprehensive
assessment and repair by a skilled HVAC technician.
Rank Building Space Recommendation
3 Warehouse
A programmable thermostat should be
installed in the warehouse and
programmed for an unoccupied and night-
time setback to 50°F.
Installation Cost $400 Estimated Life of Measure (yr) 15 Energy Savings (/yr) $914
Breakeven Cost $12,084 Savings-to-Investment Ratio 30 Simple Payback (yr) 0
Rank Building Space Recommendation
3 School
Install 20 programmable thermostats, and
implement a heating temperature night
time and unoccupied setback to 60°F for
the building.
Installation Cost $10,000 Estimated Life of Measure (yr) 15 Energy Savings (/yr) $6,847
Breakeven Cost $84,034 Savings-to-Investment Ratio 8.4 Simple Payback (yr) 2
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
21
Rank Building Space Recommendation
3 Crawlspace
The crawlspace temperature should be
reduced to 55°F for approximately
$14,000 per year in annual savings. This
may require simply replacing a
thermostat, or a more comprehensive
assessment and repair by a skilled HVAC
technician.
Installation Cost $50,000 Estimated Life of Measure (yr) 15 Energy Savings (/yr) $14,176
Breakeven Cost $186,088 Savings-to-Investment Ratio 3.7 Simple Payback (yr) 4.0
A.2 Electrical Loads
A.2.1 Lighting
The electricity used by lighting eventually ends up as heat in the building. In areas where
electricity is more expensive than other forms of energy, or in areas where the summer
temperatures require cooling; this additional heat can be both wasteful and costly. Converting
to more efficient lighting reduces cooling loads in the summer and allows the user to control
heat input in the winter. The conversion from T12 (one and a half inch fluorescent lamps) to T8
(one inch), T5 (5/8 inch), Compact Fluorescent Lights (CFL), or LED lamps provides a
significant increase in efficiency. LED lamps can be directly placed in existing fixtures. The
LED lamp bypasses the ballast altogether, which removes the often irritating, “buzzing” noise
that magnetic ballasts tend to make.
T8 lamps should be retrofitted to 17W LED lamps, which are 180° beam angle linear LED tubes
that simply bypass the existing ballast, to achieve significant energy savings. For further energy
savings in high-use areas, lighting should be controlled by occupancy sensors, and in areas
with adequate window day lighting by daylight sensor. Sensor units are available which control
lighting with both a daylight sensor and an occupancy sensor in a single device.
Exterior light fixtures should be retrofitted to LED wall packs and ceiling packs controlled by a
combination of on/off photocells and occupancy sensors.
Incandescent lamps should be retrofitted to 13W spiral CFLs.
Lighting design by a qualified professional will be required due to the extent of the EEM,
therefore some basic design costs are factored into the lighting retrofits.
Rank Location Existing Condition Recommendation
4 Incandescent 13 INCAN A Lamp, Std 100W with Manual
Switching
Replace with 13 FLUOR CFL,
Spiral 13 W
Installation Cost $60 Estimated Life of Measure (yr) 7 Energy Savings (/yr) $117
Breakeven Cost $709 Savings-to-Investment Ratio 12 Simple Payback (yr) 1
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
22
Rank Location Existing Condition Recommendation
4 T8 32W 2/1 24/7 13 FLUOR (2) T8 4' F32T8 32W Standard
Instant StdElectronic with Manual Switching
Replace with 13 LED 17W
Module StdElectronic
Installation Cost $6,500 Estimated Life of Measure (yr) 17 Energy Savings (/yr) $1,633
Breakeven Cost $20,426 Savings-to-Investment Ratio 3.1 Simple Payback (yr) 4
Rank Location Existing Condition Recommendation
4 Exterior HPS 400 Watt (2) Magnetic with Manual
Switching
Replace with LED 100W Module
StdElectronic and Add new
Occupancy Sensor, On/Off Photo
switch
Installation Cost $1,700 Estimated Life of Measure (yr) 14 Energy Savings (/yr) $318
Breakeven Cost $3,535 Savings-to-Investment Ratio 2.1 Simple Payback (yr) 5
Rank Location Existing Condition Recommendation
4
T8 32W 2/1 15/wk.
avg
86 FLUOR (2) T8 4' F32T8 32W Standard
Instant StdElectronic with Manual Switching
Replace with 86 LED (2) 17W
Module StdElectronic and Add
new Occupancy Sensor
Installation Cost $27,500 Estimated Life of Measure (yr) 16 Energy Savings (/yr) $2,404
Breakeven Cost $28,322 Savings-to-Investment Ratio 1.0 Simple Payback (yr) 11
Rank Location Existing Condition Recommendation
4 Exterior 4 INCAN [Unknown Lamp] with Manual
Switching
Replace with 4 LED (2) 80W
Module StdElectronic and Add
new Occupancy Sensor, On/Off
Photo switch
Installation Cost $4,800 Estimated Life of Measure (yr) 14 Energy Savings (/yr) $456
Breakeven Cost $5,070 Savings-to-Investment Ratio 1.1 Simple Payback (yr) 11
Rank Location Existing Condition Recommendation
4 T8 32W 2/1 school
occ
67 FLUOR (2) T8 4' F32T8 32W Standard
Instant StdElectronic with Manual Switching,
Occupancy Sensor
Replace with 67 LED 17W
Module StdElectronic
Installation Cost $25,000 Estimated Life of Measure (yr) 17 Energy Savings (/yr) $1,404
Breakeven Cost $17,293 Savings-to-Investment Ratio 0.7 Simple Payback (yr) 18
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
23
A.2.2 Other Electrical Loads
Shutting down the walk-in refrigerator and freezer and switching to smaller Energy Star chest
freezers and full-size refrigerators achieves significant energy savings and is feasible because
the student enrollment has declined significantly from the design enrollment. Additionally,
unused freezers can be shut down, which eliminates the need to maintain a large walk-in
freezer at the appropriate temperature year-round for low volumes of frozen goods.
In order to achieve additional energy savings, institute a summer shutdown of refrigerators,
remove unnecessary refrigeration capacity such as the compact refrigerator and consolidate
frozen items in order to shut down unused refrigerators and freezers.
Rank Location Existing Condition Recommendation
4 T8 32W 2/1 school
manual
248 FLUOR (2) T8 4' F32T8 32W Standard
Instant StdElectronic with Manual Switching
Replace with 248 LED (2) 17W
Module StdElectronic and Add
new Occupancy Sensor
Installation Cost $83,000 Estimated Life of Measure (yr) 17 Energy Savings (/yr) $4,007
Breakeven Cost $49,171 Savings-to-Investment Ratio 0.6 Simple Payback (yr) 21
Rank Location Existing Condition Recommendation
1 Kitchen Walk-in Refrigerator
Replace with 2 full-size Energy
Star Tier III refrigerators.
Institute seasonal shutdown and
unplug unused refrigerators.
Installation Cost $2,000 Estimated Life of Measure (yr) 7 Energy Savings (/yr) $3,100
Breakeven Cost $18,778 Savings-to-Investment Ratio 9.4 Simple Payback (yr) 1
Rank Location Existing Condition Recommendation
1 Kitchen Walk-in Freezer
Replace with up to (4) Energy
Star Chest Freezers and shut
down unused freezers when
possible.
Installation Cost $4,100 Estimated Life of Measure (yr) 7 Energy Savings (/yr) $7,494
Breakeven Cost $45,468 Savings-to-Investment Ratio 11 Simple Payback (yr) 1
Rank Location Existing Condition Recommendation
1 Compact
Refrigerator Compact Refrigerator Remove the compact
refrigerator.
Installation Cost $50 Estimated Life of Measure (yr) 7 Energy Savings (/yr) $196
Breakeven Cost $1,190 Savings-to-Investment Ratio 24 Simple Payback (yr) 0
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
24
A.3 Building Envelope: Recommendations for change
A.3.1 Exterior Walls
No EEMS are recommended in this area because construction cost makes retrofits
uneconomical.
A.3.2 Foundation and/or Crawlspace
No EEMS are recommended in this area because construction cost makes retrofits
uneconomical.
A.3.3 Roofing and Ceiling
No EEMS are recommended in this area because construction cost makes retrofits
uneconomical.
A.3.4 Windows
No EEMS are recommended in this area because construction cost makes retrofits
uneconomical.
A.3.5 Doors
No EEMS are recommended in this area because construction cost makes retrofits
uneconomical.
However, when the full-lite doors are replaced upgrade to more efficient insulated frame half-lite
doors with thermal breaks to achieve further energy savings.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
25
A.4 Building Heating System / Air Conditioning
A.4.1 Heating and Heat Distribution
Replacing the existing primary and DHW circulation pumps with appropriately sized Grundfos
Magna pumps, Grundfos Alpha pumps, or the equivalent reduces the energy consumption by at
least 50% due to the improved motor design.
Further savings can be achieved by scheduling the DHW pump to shut down at night using a
timer.
Due to the extent of the EEM, pump selection and installation by a qualified professional may be
required therefore some basic design costs are factored into the pump retrofits.
A.4.2 Air Conditioning
No EEMS are recommended in this area because there is no existing air conditioning system.
A.4.3 Ventilation
No EEMs are currently recommended in this area because of the difficulty of quantifying the
amount of ventilation air and the savings.
A.4.4 Air Changes and Air Tightening
No EEMs are recommended in this area because of the difficulty of quantifying the amount of
leaking air and the savings. However, by using a blower door to depressurize the building and
an infra-red camera, the location of significant air leaks can be determined so they can be
repaired.
Rank Location Existing Condition Recommendation
2 Boiler Room Grundfos adjustable speed pumps.
Replace all circulation pumps on
24/7 schedules with appropriate
Grundfos Magna or Alpha
models or equivalent and
schedule DHW pump flow for 16
hours a day instead of
continuous operation.
Installation Cost $22,000 Estimated Life of Measure (yr) 10 Energy Savings (/yr) $6,534
Breakeven Cost $53,647 Savings-to-Investment Ratio 2.4 Simple Payback (yr) 3
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
26
Appendix B Energy Efficiency Measures that are NOT Recommended
As indicated in other sections of the report, a number of potential EEMs were identified that
were determined to be NOT cost effective by the AkWarm model. These EEMs are not
currently recommended on the basis of energy savings alone because each may only save a
small amount of energy, have a high capital cost, or be expensive to install. While each of
these EEMs is not cost effective at this time, future changes in building use such as longer
operating hours, higher energy prices, new fixtures or hardware on the market, and decreases
in installation effort may make any of these EEMs cost effective in the future. These potential
EEMs should be reviewed periodically to identify any changes to these factors that would
warrant re-evaluation.
Although these upgrades are not currently cost effective on an energy cost basis, the fixtures,
hardware, controls, or operational changes described in these EEMs should be considered
when replacing an existing fixture or unit for other reasons. For example, replacing an existing
window with a triple-pane window may not be cost effective based only on energy use, but if a
window is going to be replaced for some other reason, then the basis for a decision is only the
incremental cost of upgrading from a less efficient replacement window to a more efficient
replacement window. That incremental cost difference will have a significantly shorter payback,
especially since the installation costs are likely to be the same for both units.
The following measures were not found to be cost-effective:
Rank Feature/Location Improvement Description
Annual
Energy
Savings
Installed
Cost
Savings to
Investment
Ratio, SIR
Simple
Payback
(Years)
9
Below- (part or all)
Grade Wall:
Crawlspace
Install R-10 rigid insulation on
basement wall $574 $17,059 0.76 30
12 Exterior Door: Metal
Full Lite
Remove existing door and
install standard pre-hung U-
0.16 insulated door, including
hardware.
$51 $2,042 0.56 40
13
On- or Below-Grade
Floor, Perimeter:
Crawlspace
Install 4' of R-5 rigid board
insulation on Perimeter of
Crawl Space Floor.
$169 $9,092 0.42 54
14 Exterior Door: Metal
1/4 Lite
Remove existing door and
install standard pre-hung U-
0.16 insulated door, including
hardware.
$21 $1,154 0.40 55
15 Exterior Door: Metal
Remove existing door and
install standard pre-hung U-
0.16 insulated door, including
hardware.
$14 $1,110 0.28 81
16 Air Tightening Perform air sealing to reduce
air leakage by 15%. $1,008 $50,000 0.18 50
17
On- or Below-Grade
Floor, Center:
Crawlspace
Install R-5 insulation on
center of basement floor $651 $118,314 0.12 180
18 Above-Grade Wall:
North Elevation
Install R-5 rigid foam board to
exterior and cover with T1-11
siding or equivalent.
$808 $236,297 0.08 290
19 Cathedral Ceiling:
School
Install R-5 rigid board
insulation. No cost included
for covering insulation.
$130 $134,947 0.02 1,000
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
27
Appendix C Significant Equipment List
HVAC Equipment
Equipment Manufacturer Model No. Notes
(2) Boilers Burnham V1107 871 MBH input.
(5) Primary Circulation Pumps Grundfos UPS 40-160 --
DHW Circulation Pump Grundfos UPS 15-42 --
Secondary Circulation Pumps varies varies Off
Heat Exchanger n/a n/a No nameplate or identifying information.
Unit Heaters and Cabinet
Heaters Various Various Includes (1) crawlspace heater.
(2) Air Handling Units *Trane Various *No nameplate or identifying information on
attic AHU.
(6) Exhaust Fans Penn Zephyr --
Indirect Hot Water Heater Amtrol Boilermate --
Lighting
Location Lighting Type Lamp
Type Quantity KWH/YR Cost/YR
Building Wide Fluorescent T8 888 55,600 $ 25,020
Gym High Bay
Fluorescent T5 60 4,900 2,205
Exterior Incandescent and
HID
150W-
400W 11 2,400 1,080
Energy Consumption calculated by AkWarm based on wattage, schedule, and an electricity rate of $0.45/kWh
Plug Loads
Equipment Location Manufacturer KWH/YR Cost/YR
Refrigerators Kitchen, various Various 43,500 $ 19,575
Range Kitchen 8,500 3,825
Office Equipment Building-wide Various 1,400 1,349
Server Rack Attic Storage Various 1,300 923
Dishwasher Kitchen Stero 1,200 540
Tools Warehouse and
Vocational Various 400 180
Energy Consumption calculated by AkWarm based on wattage, schedule, and an electricity rate of $0.45/kWh
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
28
Appendix D Local Utility Rate Structure
The information in this section was provided directly from the local utility or gathered from the
local utility’s publicly available information at the time of the audit. All language used in this
section was provided by the local utility and believed to be current at the time of the audit.
Energy use terms, specific fees, and other specific information are subject to change. Updated
rate structure information should be gathered from the utility during future discussion of rates,
rate structures and utility pricing agreements.
Utility Charge (kWh charge)
This charge is multiplied by the number of kilowatt-hours (kWh) used in a monthly billing period.
It covers the costs to maintain power plants and substations, interest on loans as well as wires,
power poles and transformers.
Fuel and Purchased Power
This charge is based on a combination of forecasted and actual power costs. The monthly
charge allows Golden Valley to pass on increases and decreases in fuel and energy purchases
to our members. It is calculated quarterly and multiplied by the kilowatt-hours used each month.
Regulatory Charge
This charge of .000492 per kWh is set by the Regulatory Commission of Alaska (RCA). Since
November 1, 1992, the Regulatory Commission of Alaska has been funded by a Regulatory
Charge to the utilities it regulates rather than through the State general fund. The charge,
labeled "Regulatory Cost Charge." on your bill, is set by the RCA, and applies to all retail
kilowatt-hours sold by regulated electric utilities in Alaska.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
29
Appendix E Analysis Methodology
Data collected was processed using AkWarm energy use software to estimate current energy
consumption by end usage and calculate energy savings for each of the proposed energy
efficiency measures (EEMs). In addition, separate analysis may have been conducted to
evaluate EEMs that AkWarm cannot effectively model to evaluate potential reductions in annual
energy consumption. Analyses were conducted under the direct supervision of a Certified
Energy Auditor, Certified Energy Manager, or a Professional Engineer.
EEMs are evaluated based on building use, maintenance and processes, local climate
conditions, building construction type, function, operational schedule and existing conditions.
Energy savings are calculated based on industry standard methods and engineering
estimations. Each model created in AkWarm is carefully compared to existing utility usage
obtained from utility bills. The AkWarm analysis provides a number of tools for assessing the
cost effectiveness of various improvement options. The primary assessment value used in this
audit report is the Savings/Investment Ratio (SIR). The SIR is a method of cost analysis that
compares the total cost savings through reduced energy consumption to the total cost of a
project over its assumed lifespan, including both the construction cost and ongoing maintenance
and operating costs. Other measurement methods include Simple Payback, which is defined as
the length of time it takes for the savings to equal the total installed cost and Breakeven Cost,
which is defined as the highest cost that would yield a Savings/Investment Ratio of one.
EEMs are recommended by AkWarm in order of cost-effectiveness. AkWarm first calculates
individual SIRs for each EEM, and then ranks the EEMs by SIR, with higher SIRs at the top of
the list. An individual EEM must have a SIR greater than or equal to one in order to be
recommended by AkWarm. Next AkWarm modifies the building model to include the installation
of the first EEM and then re-simulates the energy use. Then the remaining EEMs are re-
evaluated and ranked again. AkWarm goes through this iterative process until all suggested
EEMs have been evaluated.
Under this iterative review process, the savings for each recommended EEM is calculated
based on the implementation of the other, more cost effective EEMs first. Therefore, the
implementation of one EEM affects the savings of other EEMs that are recommended later.
The savings from any one individual EEM may be relatively higher if the individual EEM is
implemented without the other recommended EEMs. For example, implementing a reduced
operating schedule for inefficient lighting may result in relatively higher savings than
implementing the same reduced operating schedule for newly installed lighting that is more
efficient. If multiple EEMs are recommended, AkWarm calculates a combined savings.
Inclusion of recommendations for energy savings outside the capability of AkWarm will impact
the actual savings from the AkWarm projections. This will almost certainly result in lower
energy savings and monetary savings from AkWarm recommendations. The reality is that only
so much energy is consumed in a building. Energy savings from one EEM reduces the amount
of energy that can be saved from additional EEMs. For example, installation of a lower wattage
light bulb does not save energy or money if the bulb is never turned on because of a schedule
or operational change at the facility.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
30
Appendix F Audit Limitations
The results of this audit are dependent on the input data provided and can only act as an
approximation. In some instances, several EEMs or installation methods may achieve the
identified potential savings. Actual savings will depend on the EEM selected, the price of
energy, and the final installation and implementation methodology. Competent tradesmen and
professional engineers may be required to design, install, or otherwise implement some of the
recommended EEMs. This document is an energy use audit report and is not intended as a
final design document, operation, and maintenance manual, or to take the place of any
document provided by a manufacturer or installer of any device described in this report.
Cost savings are calculated based on estimated initial costs for each EEM. Estimated costs
include labor and equipment for the full up-front investment required to implement the EEM.
The listed installation costs within the report are conceptual budgetary estimates and should not
be used as design estimates. The estimated costs are derived from Means Cost Data, industry
publications, local contractors and equipment suppliers, and the professional judgment of the
CEA writing the report and based on the conditions at the time of the audit.
Cost and energy savings are approximations and are not guaranteed.
Additional significant energy savings can usually be found with more detailed auditing
techniques that include actual measurements of electrical use, temperatures in the building and
HVAC ductwork, intake and exhaust temperatures, motor runtime and scheduling, and infrared,
air leakage to name just a few. Implementation of these techniques is the difference between a
Level III Energy Audit and the Level II Audit that has been conducted.
Disclaimer: "This report was prepared as an account of work sponsored by an agency of the
United States Government. Neither the United States Government nor any agency thereof, nor
any of their employees, makes any warranty, express or implied, or assumes any legal liability
or responsibility for the accuracy, completeness, or usefulness of any information, apparatus,
product, or process disclosed, or represents that its use would not infringe privately owned
rights. Reference herein to any specific commercial product, process, or service by trade name,
trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement,
recommendation, or favoring by the United States Government or any agency thereof. The
views and opinions of authors expressed herein do not necessarily state or reflect those of the
United States Government or any agency thereof."
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
31
Appendix G References
Although not all documents listed below are specifically referenced in this report, each contains
information and insights considered valuable to most buildings.
Alaska Department of Education and Early Development; Education Support Services/Facilities.
(1999). Alaska School Facilities Preventative Maintenance Handbook. Juneau, AK:
Alaska Department of Education and Early Development.
Alaska Housing Finance Corportation. (2011). Retrofit Energy Assessment for Loans. AHFC.
ASHRAE. (1997). 1997 ASHRAE Handbook: Fundamentals. Atlanta, GA: ASHRAE.
ASHRAE. (2007). ASHRAE Standard 105-2007 Expressing and Comparing Building Energy
Performance. Retrieved from ASHRAE: www.ashrae.org
ASHRAE. (2007). ASHRAE Standard 90.1-2007 Energy Standards for buildings Except Low-
Rise Residential Buildings. Retrieved from ASHRAE: www.ashrae.org
ASHRAE. (2011). ASHRAE Standard 62.1-2011 Ventilaton for Acceptable Indoor Air Quality.
Retrieved from ASHRAE: www.ashrae.org
ASHRAE. (2011). ASHRAE Standard 62.2-2011 Ventilation and Acceptable Indoor Air Quality in
Low Rise Residential Buildings. Retrieved from ASHRAE: www.ashrae.org
ASHRAE RP-669 and SP-56. (2004). Procedures for Commercial Building Energy Audits.
Atlanta, GA: ASHRAE.
Coad, W. J. (1982). Energy Engineering and Management for Building Systems. Scarborough,
Ontario, Canada: Van Nostrand Reinhold Company.
Daley, D. T. (2008). The Little Black Book of Reliability Management. New York, NY: Industrial
Press, Inc.
Federal Energy Management Program. (2004, March 3). Demand Controlled Ventilation Using
CO2 Sensors. Retrieved 2011, from US DOE Energy Efficiency and Renewable Energy:
http://www.eere.energy.gov/femp/pdfs/fta_co2.pdf
Federal Energy Management Program. (2006, April 26). Low-Energy Building Design
Guidelines. Retrieved 2011, from Department of Energy; Federal Energy Management
Program: http://www.eren.doe.gov/femp/
Institute, E. a. (2004). Variable Speed Pumping: A Guide to Successful Applications. Oxford,
UK: Elsevier Advanced Technology.
International Code Council. (2009). International Energy Conservation Code. Country Club Hills,
IL: International Code Council, Inc.
Leach, M., Lobato, C., Hirsch, A., Pless, S., & Torcellini, P. (2011, September). Technical
Support Document: Strategies for 50% Energy Savings in Large Office Buildings.
Retrieved 2011, from National Renewable Energy Laboratory:
http://www.nrel.gov/docs/fy10osti/49213.pdf
Thumann, P.E., C.E.M., A., Younger, C.E.M., W. J., & Niehus, P.E., C.E.M., T. (2011).
Handbook of Energy Audits Eighth Edition. Lilburn, GA: The Fairmont Press, Inc.
U.S. Energy Information Administration. (2006). Commercial Building Energy Consumption
Survey (CBECS). Retrieved 2011, from Energy Information Administration:
http://www.eia.gov/emeu/cbecs/
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
32
Appendix H Typical Energy Use and Cost – Fairbanks and Anchorage
This report provides data on typical energy costs and use on selected building in Fairbanks and
Anchorage, Alaska for comparative purposes only. The values provided by the US Energy
Information Administration CBECS study included a broader range of building types for the
Continental U.S. are not necessarily good comparatives for buildings and conditions in Alaska.
An assortment of values from CBECS may be found in Appendix I.
The Alaska data described in this report came from a benchmarking study NORTECH and other
Technical Services Providers (TSPs) completed on publicly owned buildings in Alaska under
contract with AHFC. This study acquired actual utility data for municipal buildings and schools
in Alaska for the two recent full years. The utility data included costs and quantities including
fuel oil, electricity, propane, wood, steam, and all other energy source usage. This resulted in a
database of approximately 900 buildings. During the course of the benchmarking study, the
comparisons made to the CBECS data appeared to be inappropriate for various reasons.
Therefore, this energy use audit report references the average energy use and energy cost of
Anchorage and Fairbanks buildings as described below.
The Alaska benchmarking data was evaluated in order to find valid comparison data. Buildings
with major energy use information missing were eliminated from the data pool. After detailed
scrutiny of the data, the most complete information was provided to NORTECH by the
Fairbanks North Star Borough School District (FNSBSD) and the Anchorage School District
(ASD). The data sets from these two sources included both the actual educational facilities as
well as the district administrative buildings and these are grouped together in this report as
Fairbanks and Anchorage schools. These two sources of information, being the most complete
and reasonable in-state information, have been used to identify an average annual energy
usage for Fairbanks and for Anchorage in order to provide a comparison for other facilities in
Alaska.
Several factors may limit the comparison of a specific facility to these regional indicators. In
Fairbanks, the FNSBSD generally uses number two fuel oil for heating needs and electricity is
provided by Golden Valley Electric Association (GVEA). GVEA produces electricity from a coal
fired generation plant with additional oil generation upon demand. A few of the FNSBSD
buildings in this selection utilize district steam and hot water. The FNSBSD has recently (the
last ten years) invested significantly in envelope and other efficiency upgrades to reduce their
operating costs. Therefore a reader should be aware that this selection of Fairbanks buildings
has energy use at or below average for the entire Alaska benchmarking database.
Heating in Anchorage is through natural gas from the nearby natural gas fields. Electricity is
also provided using natural gas. As the source is nearby and the infrastructure for delivery is in
place, energy costs are relatively low in the area. As a result, the ASD buildings have lower
energy costs, but higher energy use, than the average for the entire benchmarking database.
These special circumstances should be considered when comparing the typical annual energy
use for particular buildings.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
33
Appendix I Typical Energy Use and Cost – Continental U.S.
Released: Dec 2006
Next CBECS will be conducted in 2007
Table C3. Consumption and Gross Energy Intensity for Sum of Major Fuels for Non-Mall Buildings, 2003
All Buildings* Sum of Major Fuel Consumption
Number of
Buildings
(thousand)
Floor
space
(million
square
feet)
Floor space
per Building
(thousand
square feet)
Total
(trillion
BTU)
per
Building
(million
BTU)
per
Square Foot
(thousand
BTU)
per
Worker
(million
BTU)
All Buildings* 4,645 64,783 13.9 5,820 1,253 89.8 79.9
Building Floor space (Square Feet)
1,001 to 5,000 2,552 6,789 2.7 672 263 98.9 67.6
5,001 to 10,000 889 6,585 7.4 516 580 78.3 68.7
10,001 to 25,000 738 11,535 15.6 776 1,052 67.3 72.0
25,001 to 50,000 241 8,668 35.9 673 2,790 77.6 75.8
50,001 to 100,000 129 9,057 70.4 759 5,901 83.8 90.0
100,001 to 200,000 65 9,064 138.8 934 14,300 103.0 80.3
200,001 to 500,000 25 7,176 289.0 725 29,189 101.0 105.3
Over 500,000 7 5,908 896.1 766 116,216 129.7 87.6
Principal Building Activity
Education 386 9,874 25.6 820 2,125 83.1 65.7
Food Sales 226 1,255 5.6 251 1,110 199.7 175.2
Food Service 297 1,654 5.6 427 1,436 258.3 136.5
Health Care 129 3,163 24.6 594 4,612 187.7 94.0
Inpatient 8 1,905 241.4 475 60,152 249.2 127.7
Outpatient 121 1,258 10.4 119 985 94.6 45.8
Lodging 142 5,096 35.8 510 3,578 100.0 207.5
Retail (Other Than Mall) 443 4,317 9.7 319 720 73.9 92.1
Office 824 12,208 14.8 1,134 1,376 92.9 40.3
Public Assembly 277 3,939 14.2 370 1,338 93.9 154.5
Public Order and Safety 71 1,090 15.5 126 1,791 115.8 93.7
Religious Worship 370 3,754 10.1 163 440 43.5 95.6
Service 622 4,050 6.5 312 501 77.0 85.0
Warehouse and Storage 597 10,078 16.9 456 764 45.2 104.3
Other 79 1,738 21.9 286 3,600 164.4 157.1
Vacant 182 2,567 14.1 54 294 20.9 832.1
This report references the Commercial Buildings Energy Consumption Survey (CBECS), published by the U.S.
Energy Information Administration in 2006. Initially this report was expected to compare the annual energy
consumption of the building to average national energy usage as documented below. However, a direct comparison
between one specific building and the groups of buildings outlined below yielded confusing results. Instead, this
report uses a comparative analysis on Fairbanks and Anchorage data as described in Appendix F. An abbreviated
excerpt from CBECS on commercial buildings in the Continental U.S. is below.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
34
Appendix J List of Conversion Factors and Energy Units
1 British Thermal Unit is the energy required to raise one pound of water one degree F°
1 Watt is approximately 3.412 BTU/hr.
1 horsepower is approximately 2,544 BTU/hr.
1 horsepower is approximately 746 Watts
1 "ton of cooling” is approximately 12,000 BTU/hr., the amount of power required
to melt one short ton of ice in 24 hours
1 Therm = 100,000 BTU
1 KBTU = 1,000 BTU
1 KWH = 3413 BTU
1 KW = 3413 BTU/Hr.
1 Boiler HP = 33,400 BTU/Hr.
1 Pound Steam = approximately 1000 BTU
1 CCF of natural gas = approximately 1 Therm
1 inch H2O = 250 Pascal (Pa) = 0.443 pounds/square inch (psi)
1 atmosphere (atm) = 10,1000 Pascal (Pa)
BTU British Thermal Unit
CCF 100 Cubic Feet
CFM Cubic Feet per Minute
GPM Gallons per minute
HP Horsepower
Hz Hertz
kg Kilogram (1,000 grams)
kV Kilovolt (1,000 volts)
kVA Kilovolt-Amp
kVAR Kilovolt-Amp Reactive
KW Kilowatt (1,000 watts)
KWH Kilowatt Hour
V Volt
W Watt
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
35
Appendix K List of Acronyms, Abbreviations, and Definitions
ACH Air Changes per Hour
AFUE Annual Fuel Utilization Efficiency
Air Economizer A duct, damper, and automatic control system that
allows a cooling system to supply outside air to reduce
or eliminate the need for mechanical cooling.
Ambient Temperature Average temperature of the surrounding air
Ballast A device used with an electric discharge lamp to cause
the lamp to start and operate under the proper circuit
conditions of voltage, current, electrode heat, etc.
CO2 Carbon Dioxide
CUI Cost Utilization Index
CDD Cooling Degree Days
DDC Direct Digital Control
EEM Energy Efficiency Measure
EER Energy Efficient Ratio
EUI Energy Utilization Index
FLUOR Fluorescent
Grade The finished ground level adjoining a building at the
exterior walls
HDD Heating Degree Days
HVAC Heating, Ventilation, and Air-Conditioning
INCAN Incandescent
NPV Net Present Value
R-value Thermal resistance measured in BTU/Hr.-SF-̊F (Higher
value means better insulation)
SCFM Standard Cubic Feet per Minute
Savings to Investment Ratio (SIR) Savings over the life of the EEM divided by Investment
capital cost. Savings includes the total discounted dollar
savings considered over the life of the improvement.
Investment in the SIR calculation includes the labor and
materials required to install the measure.
Set Point Target temperature that a control system operates the
heating and cooling system
Simple payback A cost analysis method whereby the investment cost of
an EEM is divided by the first year’s savings of the EEM
to give the number of years required to recover the cost
of the investment.
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
36
Appendix L Building Floor Plan
Warehouse
Energy Audit – Final Report
McGrath School
McGrath, Alaska
F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-395 Iditarod Area SD\50-397 Mcgrath School\Reports\Final\2012.07.12 Final AHFC
Report V2 MCG K12 School.Docx
37