NREL is a national laboratory of the U.S. Department of Energy, Office of Energy 

Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Contract No. DE-AC36-08GO28308

Hawaii-Okinawa Building 

Evaluations

I. Metzger and J. Salasovich 

National Renewable Energy Laboratory

Technical Report

NREL/TP-7A40-57285

May 2013 
NREL is a national laboratory of the U.S. Department of Energy, Office of Energy 

Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

National Renewable Energy Laboratory

15013 Denver West Parkway

Golden, Colorado 80401

303-275-3000 • www.nrel.gov

Contract No. DE-AC36-08GO28308

 

Hawaii-Okinawa Building 

Evaluations 

I. Metzger and J. Salasovich

National Renewable Energy Laboratory

Prepared under Task No. IGIN.3300

Technical Report

NREL/TP-7A40-57285

May 2013
NOTICE

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Cover Header Photos: (left to right) PIX 16416, PIX 17423, PIX 16560, PIX 17613, PIX 17436, PIX 17721

Cover Photos: Hawaii State Capitol (left) and Itoman City Hall (right) (Credit: Jimmy Salasovich)

Printed on paper containing at least 50% wastepaper, including 10% post consumer waste. 
iv

CONTACTS AND TEAM MEMBERS 

Department of Energy

Michael Mills

EERE International Programs

Phone: 202-586-6653 

Email: michael.mills@ee.doe.gov

Ron Cherry 

Senior Policy Advisor 

Office of East Asian Affairs (PI-34)

Phone: 202-586-2285 

Email: ron.cherry@hq.doe.gov

Tsering Dhongthog 

Office of East Asian Affairs (PI-34)

Phone: 202-586-3698 

Email: Tsering.Dhongthog@hq.doe.gov

State of Hawaii

Carilyn Shon * 

Energy Conservation Program Manager 

Strategic Industries Division

Phone: 808-587-3810 

Fax: 808-586-2536 

Email: cshon@dbedt.hawaii.gov

Okinawa Prefecture

Katsuyuki Ohama * 

Senior Staff, Industrial Policy Division

Department of Commerce, Industry 

and Labor 

Phone: 81-98-866-2330 

Email: oohamaka@pref.okinawa.lg.jp

National Renewable Energy 

Laboratory

Kate Anderson 

Project Lead, Manager

Phone: 303-384-7453 

Fax: 303-275-3007 

Email: kate.anderson@nrel.gov 

Ian Metzger *# 

Engineer III

Phone: 303-384-7415 

Fax: 303-275-3007 

Email: ian.metzger@nrel.gov 

Jimmy Salasovich *# 

Engineer III

Phone: 303-384-7383 

Fax: 303-275-3007 

Email: james.salasovich@nrel.gov

* Members of the Site Assessment Team 

# Report authors to whom any questions 

should be directed 
1 

ACKNOWLEDGMENTS

The National Renewable Energy Laboratory team thanks the U.S. Department of Energy 

(DOE) Office of Energy Efficiency and Renewable Energy (EERE) for the opportunity to 

perform the building evaluations at Itoman City Hall building in Okinawa, Japan, and the 

Hawaii State Capitol building in Honolulu, Hawaii. In particular, the assessment team is 

grateful to the facility managers, directors, engineers, and operators for their generous 

assistance and cooperation. Special thanks to Carilyn Shon and Katsuyuki Ohama for their 

assistance coordinating the evaluations. 
2 

LIST OF ACRONYMS

AC alternating current

AEDG Advanced Energy Design Guide 

AHU air-handling unit 

ASHRAE American Society of Heating, Refrigerating, and Air-Conditioning Engineers 

BAS building automation system

BF ballast factor

CAV constant air volume

CBECS Commercial Building Energy Consumption Survey 

CDD cooling degree days 

CFL compact fluorescent lighting

DC direct current 

DOE Department of Energy 

DOAS dedicated outside air system

DHW domestic hot water

ECM energy conservation measure 

EE energy efficiency 

EER energy efficiency ratio

EPD equipment power density 

EUI energy use intensity

HECO Hawaiian Electric Company

HVAC heating, ventilation, and air conditioning

IEEE Electrical and Electronic Engineers

IES Illuminating Engineering Society

IPLV integrated part load value

ITC investment tax credit

LCD liquid crystal display

METI Ministry of Economy, Trade and Industry 

NEMA National Electrical Manufacturers Association

NREL National Renewable Energy Laboratory 

OPR owner’s project requirements

PPA power purchase agreement

PV photovoltaic 

RE renewable energy

RH relative humidity

SHGC solar heat gain coefficient

SHW solar hot water

SRI solar reflectance index

TMY typical meteorological year

VFD variable-frequency drives

VT visual transmittance

WSHP water source heat pumps 
3 

EXECUTIVE SUMMARY

NREL conducted energy evaluations at the Itoman City Hall building in Itoman, Okinawa 

Prefecture, Japan, and the Hawaii State Capitol building in Honolulu, Hawaii. This report 

summarizes the findings from the evaluations, including the best practices identified at each 

site and opportunities for improving energy efficiency and renewable energy. The findings 

from this evaluation are intended to inform energy efficient building design, energy efficiency 

technology, and management protocols for buildings in subtropical climates. 

The five-story Itoman City Hall building is 166,130 ft2 (15,434 m2) and houses approximately 

400 occupants. The building’s primary function is office space, but it also includes storage, 

machine rooms, and other types of space. The climate in Itoman features some variations in 

temperature from season to season with consistently high humidity and precipitation year 

round. Itoman experiences approximately 3,399 cooling degree days1 per year. The annual 

electricity use for the Itoman City Hall in 2011 was 1,777,604 kWh at a cost of $465,848 

(39,597,062 Yen). The energy use intensity (EUI) in 2011 was approximately 37 kBtu/ft2

(115 kWh/m2

). 

The six-story Hawaii State Capitol building is 188,485 ft2 and houses 300 occupants

continuously, and up to approximately 900 occupants when the legislature is in session. The 

building’s primary function is office space, but it also includes auditoriums, conference 

rooms, and other types of space. The climate in Honolulu features small variations in 

temperature from season to season with moderate humidity and precipitation year round. 

Honolulu experiences approximately 4,965 cooling degree days per year. The annual 

electricity use for the Hawaii State Capitol building in 2011 was 4,765,600 kWh at a cost of 

$1,397,433. The EUI in 2011 was approximately 86 kBtu/ft2 (271 kWh/m2). 

Throughout the building evaluations, several best practices and opportunities were observed.

Table 1 shows the best practices for both buildings, with the best practices found at both sites 

listed in the center column. Table 2 shows the opportunities for both buildings with the 

opportunities found at both sites listed in the center column. 

 

1 Degree day is a quantitative index of the demand for energy to heat or cool buildings. A mean daily 

temperature of 65°F is the base for both heating and cooling degree day computations. Source: 

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/cdus/degree_days/ddayexp.shtml
4 

Table 1. Summary of Best Practices Observed During the Building Evaluations

Itoman City Hall Building Best Practices Observed at 

Both Sites

Hawaii State Capitol 

Building

Energy saving temperature set

points (27oC, 80oF)

Knowledgeable, proactive, 

and competent facilities staff

Cooling tower fan 

sequencing 

Central lighting controls for 

scheduling 

Good preventative 

maintenance schedules

Premium efficiency 

motors 

No cubicle walls allows better 

views, ventilation, and daylight 

De-lamped lighting fixtures 

in many spaces 

Lighting occupancy 

sensors 

Ice storage system to reduce 

peak daytime loads 

Good shading on exterior of 

building 

Bi-level light 

switching

Use of rainwater for toilets and 

urinals

Liquid crystal display (LCD) 

computer monitors

Vending machine 

misers

Operable windows with cross 

ventilation 

Central building automation 

system

Energy awareness and 

education campaign 

Air-side economizer based on 

outdoor air temperature 

T8 and compact fluorescent 

lighting (CFL) lighting

Vestibule doors at entrances Variable speed drives

Window tint on west windows LED exit signs

Permeable paving in parking lot Electronic controls

195-kW PV system Well-insulated pipes

Demand response High thermal mass building

Table 2. Summary of Opportunities Observed During the Building Evaluations

Itoman City Hall Building Opportunities Observed at 

Both Sites

Hawaii State Capitol 

Building

De-lamp overlit spaces Cogged V-belts on fan drives Install PV system 

Use premium efficiency motors Convert constant air volume 

system to variable air volume 

Utilize demand control 

ventilation 

Consider replacing inverter with 

high efficiency inverter

Reduce ventilation rates to 

ASHRAE 62.1-2010 levels

Procure ENERGY 

STAR refrigerators

Investigate the performance of 

the current PV system

Replace desktop computers 

with low-energy desktops 

Place timers on 

specific plug loads

Investigate corrosion prevention 

options for chillers

Consolidate the number of 

networked printers

Activate computer 

power management

Replace large chillers w/

smaller packaged units

Replace metal halide, halogen, 

and CFL lighting with LEDs 

Install solar water 

heating system 

 Install lighting occupancy 

sensors 
5 

The opportunities were analyzed for energy and cost savings. The total potential savings for 

the opportunities found at Itoman City Hall building were 738,978 kWh/yr, or $204,988/yr, 

with a combined simple payback period of 10.2 years. Table 3 lists the energy conservation 

measures for the Itoman City Hall building. The total potential savings for the opportunities 

found at the Hawaii State Capitol building were 2,015,003 kWh/yr, or $619,715/yr, with a 

combined simple payback period of 5.0 years. Table 4 lists the energy conservation measures 

for the Hawaii State Capitol building. 

Note that the energy conservation measures summarized in the tables below do not include 

interactions between measures. The simple summation of savings for multiple conservation 

measures could be an overestimation. 

Table 3. Itoman City Hall Building Energy Conservation Measures

Energy and Water 

Conservation 

Measures

Category

Annual 

Electricity 

Savings 

(kWh/yr)

Annual 

Cost 

Savings 

($)

Annual 

Operations 

and 

Maintenance 

Costs ($)

Implementation 

Costs ($)

Simple 

Payback 

Period 

(yrs)

Greenhouse 

Gas 

Reduction 

(lbs CO2e)

Consolidate Network 

Printers 

Plug 

Loads 16,487 $5,959 $0 $4,778 0.8 13.1 

Replace the Standard 

V-Belts with Cogged 

V-Belts

HVAC 5,189 $1,430 $0 $2,210 1.6 4.1 

De-lamp Over

Illuminated Spaces Lighting 6,925 $1,981 $0 $3,413 1.7 5.5 

Install Low-Flow 

Aerators on Faucets Water 85,167 gal. water $1,703 $0 $3,120 1.8 0.0 

Retrofit Metal Halide 

and Halogen Lighting 

with LED

Lighting 45,982 $13,227 $0 $55,361 4.2 36.4 

Reduce Ventilation 

Rates to ASHRAE 

62.1-2007 Levels

HVAC 17,916 $5,182 $0 $31,200 6.0 14.2 

Replace Desktop 

Computers with LowEnergy Desktops

Plug 

Loads 105,911 $30,878 $0 $278,200 9.0 83.9 

Replace the Standard 

Motors with High 

Efficiency Motors

HVAC 8,101 $2,413 $0 $23,332 9.7 6.4 

Replace T-12 Lamps 

and Magnetic Ballasts 

with Low Wattage T8 Lamps 

andelectronic. 

Ballasts

Lighting 1,989 $590 $0 $6,143 10.4 1.6 

Convert Constant Air 

Volume Distribution 

to Variable Air 

Volume

HVAC 531,573 $141,384 $0 $1,687,966 11.9 419.9 

Install Occupancy 

Sensors in 

Bathrooms, 

Conference Rooms, 

and Private Offices

Lighting 895 $241 $0 $3,016 12.5 0.7 

Total 738,978 $204,988 $0 $2,098,737 10.2 585.8
6 

Table 4. Hawaii State Capitol Building Energy Conservation Measures

Energy

Conservation 

Measures

Category

Annual 

Electricity 

Savings 

(kWh/yr)

Annual 

Cost 

Savings 

($)

Annual 

Operations 

and 

Maintenance 

Costs ($)

Implementation 

Costs ($)

Simple 

Payback 

Period 

(yrs)

Greenhouse 

Gas 

Reduction 

(metric 

tons CO2e)

Replace the 

Standard V-Belts 

with High 

Efficiency 

Cogged V-Belts

HVAC 9,542 $3,268 $0 $2,214 0.7 7.6 

Replace 

Refrigerator with 

ENERGY STAR

Refrigerator

Plug Loads 3,279 918 $0 1,014 1.1 2.6 

Reduce 

Ventilation 

Rates to 

ASHRAE 62.1-

2007 Levels

HVAC 48,955 $15,550 $0 $31,200 2.0 38.7 

Activate 

Computer Power 

Management

Plug Loads 49,784 $13,940 $8,680 $12,545 2.4 39.5 

Convert 

Constant Air 

Volume 

Distribution to 

Variable Air 

Volume

HVAC 1,353,035 $407,404 $0 $1,909,720 4.7 1,083.3 

Retrofit Metal 

Halide, 

Incandescent, 

and CFL 

Lighting with 

LED

Lighting 200,110 $76,142 $0 $415,249 5.5 158.6 

Install PV 

System on the 

Southeast Lawn

Renewables 285,434 $79,922 $2,250 $523,598 6.7 226.0 

Install 

Occupancy 

Sensors in 

Bathrooms, 

Conference 

Rooms, and 

Private Offices

Lighting 5,433 $1,521 $0 $10,556 6.9 4.3 

Replace Desktop 

Computers with 

Low-Energy 

Desktop 

Computers

Plug Loads 59,431 $21,051 $0 $161,200 7.7 47.1 

Total 2,015,003 $619,715 $10,930 $3,067,296 5.0 1,607.70
7 

TABLE OF CONTENTS

CONTACTS AND TEAM MEMBERS ..............................................................................................................iv

ACKNOWLEDGMENTS ..................................................................................................................................... 1

LIST OF ACRONYMS ......................................................................................................................................... 2

EXECUTIVE SUMMARY ................................................................................................................................... 3

TABLE OF CONTENTS ...................................................................................................................................... 7

LIST OF TABLES................................................................................................................................................. 8

LIST OF FIGURES............................................................................................................................................... 9

BACKGROUND ..................................................................................................................................................10

Building Description—Itoman City Hall Building ............................................................................................11

Building Description—Hawaii State Capitol Building......................................................................................13

CLIMATE DATA................................................................................................................................................15

UTILITY DATA ..................................................................................................................................................17

BEST PRACTICES AND OBSERVATIONS...................................................................................................20

50% Design Guide Recommendations...............................................................................................................20

Summary of Best Practices Observed................................................................................................................24

Energy Efficiency, Water Efficiency, and Renewable Energy Opportunities....................................................26

APPENDIX A: DETAILED ENERGY ANALYSIS FOR ITOMAN CITY HALL BUILDING .................28

Building Energy Modeling................................................................................................................................. 28

Energy Efficiency and Renewable Energy Opportunities..................................................................................30

APPENDIX B: DETAILED ENERGY ANALYSIS FOR HAWAII STATE CAPITOL BUILDING.........44

Building Energy Modeling................................................................................................................................. 44

Energy Efficiency and Renewable Energy Opportunities..................................................................................46
8 

LIST OF TABLES

Table 1. Summary of Best Practices Observed During the Building Evaluations ........................................... 4

Table 2. Summary of Opportunities Observed During the Building Evaluations ........................................... 4

Table 3. Itoman City Hall Building Energy Conservation Measures................................................................ 5

Table 4. Hawaii State Capitol Building Energy Conservation Measures ......................................................... 6

Table 5. 2011 Historic Weather Summary ........................................................................................................15

Table 6. Summary of Best Practices Observed During the Building Evaluations .........................................24

Table 7. Summary of Opportunities Observed During the Building Evaluations .........................................26

Table 8. Energy and Cost Savings Summary for Replacing V-Belts...............................................................31

Table 9. Energy and Cost Savings Summary for Reducing Ventilation Rates...............................................32

Table 10. Energy and Cost Savings Summary for Converting CAV to VAV System....................................33

Table 11. Existing Motor Inventory ...................................................................................................................34

Table 12. Energy and Cost Savings Summary for Installing Premium Efficiency Motors...........................34

Table 13. IES-Recommended Light Levels by Task Area................................................................................35

Table 14. Energy and Cost Savings Summary for De-Lamping......................................................................36

Table 15. Energy and Cost Savings Summary for Installing Occupancy Sensors .........................................38

Table 16. Inventory and Location of Existing Lamps.......................................................................................38

Table 17. LED-Equivalent Lamp Wattages and Costs.....................................................................................38

Table 18. Energy and Cost Savings Summary for LED Lighting....................................................................39

Table 19. Energy and Cost Savings Summary for T8 Lighting .......................................................................39

Table 20. Energy and Cost Savings Summary for Low-Energy Desktops......................................................40

Table 21. Energy and Cost Savings Summary for Low-Energy Desktops......................................................41

Table 22. Energy and Cost Savings Summary for Low-Flow Aerators..........................................................42

Table 23. Comparison of PV Performance Simulation to Actual....................................................................43

Table 24. Observed Fan Drives with Standard V-belts....................................................................................46

Table 25. Energy and Cost Savings Summary for Replacing V-Belts.............................................................47

Table 26. Energy and Cost Savings Summary for Converting CAV to VAV System....................................48

Table 27. Energy and Cost Savings Summary for Reducing Ventilation Rates.............................................49

Table 28. Energy and Cost Savings Summary for Installing Occupancy Sensors .........................................51

Table 29. Inventory and Location of Existing Lamps.......................................................................................51

Table 30. LED-Equivalent Lamp Wattages and Costs.....................................................................................52

Table 31. Energy and Cost Savings Summary for LED Lighting....................................................................52

Table 32. Energy and Cost Savings Summary for ENERGY STAR-Rated Refrigerators ...........................53

Table 33. Energy and Cost Savings Summary for Activating Computer Power Management ....................54

Table 34. Energy and Cost Savings Summary for Low-Energy Desktops......................................................55

Table 35. PV System Specifications and Results...............................................................................................60
9 

LIST OF FIGURES

Figure 1: Aerial view of Itoman City Hall in Okinawa, Japan; photo of north façade ................................. 11

Figure 2: Aerial view of Hawaii State Capitol in Honolulu, Hawaii; photo of southeast façade ..................13

Figure 3. Annual weather data plotted on a psychrometric chart: Itoman (top), Honolulu (bottom) .........16

Figure 4. Itoman City Hall electricity usage (top), rates (middle), cost allocation (bottom) .........................18

Figure 5. Hawaii State Capitol electricity usage (top), rates (middle), cost allocation (bottom)...................19

Figure 6. Example cross section of exterior wall with continuous insulation .................................................20

Figure 7. Example of premium efficiency pump motor....................................................................................21

Figure 8. Example of heat pump service water heater .....................................................................................21

Figure 9. Example of window shading (left) and sunlight redirection device (right).....................................22

Figure 10. Example of various plug load control devices.................................................................................23

Figure 11. Example of waterless urinal..............................................................................................................23

Figure 12. Example of rooftop photovoltaic system..........................................................................................23

Figure 13. Itoman City Hall building photovoltaic system (left) and cold brine storage (right)...................25

Figure 14. Energy awareness and education campaign observed at the Hawaii State Capitol building......25

Figure 15. Standard V-belt fan motor drive at Itoman City Hall building.....................................................27

Figure 16. Nighttime exterior metal halide lighting at Hawaii State Capitol building ..................................27

Figure 19. Cogged V-belt (left) and standard V-belt (right) ............................................................................30

Figure 20. Typical wall-switch lighting occupancy sensor ...............................................................................36

Figure 21. Typical ceiling-mounted lighting occupancy sensor coverage (top) and application (bottom)...37

Figure 24. Cogged V-belt (left) and standard V-belt (right) ............................................................................46

Figure 25. Typical wall-switch lighting occupancy sensor ...............................................................................50

Figure 26. Typical ceiling-mounted lighting occupancy sensor coverage (top) and application (bottom)...50

Figure 27. Plug-load occupancy sensor ..............................................................................................................56

Figure 28. Major components of grid-connected PV system............................................................................57

Figure 29. Available ground area for a PV system at the Hawaii State Capitol building .............................59
10 

BACKGROUND

In support of the U.S.–Japan Energy Policy Dialogue, the four participants (the U.S. 

Department of Energy (DOE), the Japanese Ministry of Economy, Trade and Industry 

(METI), the State of Hawaii, and the Prefecture of Okinawa) of the Hawaii-Okinawa 

Partnership on Clean and Efficient Energy Development and Deployment have explored and 

identified specific joint projects that support both Hawaii’s and Okinawa’s efforts to develop 

clean energy economies as well as identified additional areas to explore in the future. There 

are many countries that are located in subtropical and tropical areas, most of which are rapidly 

expanding their energy consumption and are in need of energy efficient buildings. Hawaii and 

Okinawa share this need. However, most work on energy efficient buildings has been done 

for countries in temperate climates. Therefore, energy efficiency building design, energy 

efficiency technology, and management protocols for buildings in subtropical and tropical 

areas offer significant potential for mutually beneficial cooperation.

DOE’s National Renewable Energy Laboratory (NREL) is solely dedicated to advancing 

energy efficient (EE) and renewable energy (RE) technologies and applications. Since its 

inception, NREL has supported both the federal and the private sectors in implementing EE 

and RE systems and strategies to lower energy use and to meet remaining energy needs with 

resources having minimal environmental impact. NREL assistance was requested to conduct 

energy evaluations at the Itoman City Hall building in Itoman, Okinawa Prefecture, Japan, on 

March 20–24, 2012, and the Hawaii State Capitol building in Honolulu, Hawaii, on July 23–

27, 2012. This report summarizes the findings from the evaluations, including the best 

practices identified at each site and opportunities for improving energy efficiency and 

renewable energy in buildings. 
11 

Building Description—Itoman City Hall Building

Overview

The Itoman City Hall building is located at 1-1 Shiozakicho Itoman, Okinawa Prefecture, 

Japan. The five-story building is 166,130 ft2 (15,434 m2) and houses approximately 400 

occupants. The building’s primary function is office space, but it also includes storage,

machine rooms, and other types of space. Figure 1 shows an aerial view of the Itoman City 

Hall building from Google Earth and a photo of the north façade of the building. 

Figure 1: Aerial view of Itoman City Hall in Okinawa, Japan; photo of north façade 

Left photo: © Google Earth 2012; right photo: Ian Metzger, NREL

Occupancy

The occupancy schedule for the Itoman City Hall building is relatively constant at 8:00 a.m. 

to 5:00 p.m. Monday through Friday. The building is primarily unoccupied on the weekends. 

Building Envelope

The building architecture was based on Chinese geomancy, with an exterior composed of 

reinforced concrete, concrete flat roof, and shading structures called Amahaji (similar to 

eaves) holding photovoltaic (PV) panels. The building has a square footprint with a central 

courtyard and auxiliary building branching from the west façade. The fenestration includes a 

combination of operable and fixed windows, with tints applied to the west-facing windows. 

Heating, Ventilation, and Air Conditioning

The heating, ventilation, and air conditioning (HVAC) system is a constant air volume (CAV) 

system and some spaces have with direct-expansion split systems for supplemental cooling. 

The HVAC system is scheduled to operate between 8:00 a.m. and 5:00 p.m. on weekdays and 

be off at night and during the weekends. There is an economizer that economizes based on the 

outside air temperature.

Cooling Plant

The chilled water system includes three chillers—one 300-kW air-cooled chiller and two 245-

kW air-cooled brine chillers for thermal storage. The brine chillers are operated at night to 

avoid high time-of-use electricity rates. Ice storage tanks on the roof supply cooling during 

the day, in conjunction with the air-cooled chiller if needed. Chilled water is distributed 
12 

through constant-speed pumping for the 300-kW chiller and variable-speed pumping for the 

brine chillers. 

Domestic Hot Water

Domestic hot water (DHW) is supplied by distributed electric hot water tanks. 

Building Automation System 

The HVAC systems, including air-handling units (AHUs), chillers, pumps, and lighting, are 

controlled by a Johnson Controls building automation system (BAS). Schedules and set points 

for the various pieces of equipment are implemented through the BAS. 

Lighting

A majority of the fixtures use T-8 fluorescent lamps with electronic ballasts. The lighting 

systems are controlled by the central building automation system. Some less efficient 

incandescent lamps were also observed in the lobby and display areas. 

Plug Loads

The primary electrical plug load in the facility consists of the office equipment. The main 

office equipment loads are associated with the desktop computer workstations, printers, and 

copiers. There are a few small data closets throughout the building but no major data centers. 
13 

Building Description—Hawaii State Capitol Building

Overview

The Hawaii State Capitol building is located at 415 S. Beretania St., Honolulu, Hawaii. The sixstory building is 188,485 ft2

 and houses 300 occupants continuously, and up to approximately 

900 occupants when the legislature is in session. The building’s primary function is office 

space, but it also includes auditoriums, conference rooms, and other types of space. Figure 2

shows an aerial view of the Hawaii State Capitol building from Google Earth and a photo of 

the southeast façade of the building. 

Figure 2: Aerial view of Hawaii State Capitol in Honolulu, Hawaii; photo of southeast façade 

Left photo: © Google Earth 2012; right photo: Ian Metzger, NREL

Occupancy

The occupancy schedule for the Hawaii State Capitol building is 7:00 a.m. to 4:30 p.m. 

Monday through Friday when the legislature is not in session (June–November). However, 

occupant schedules vary widely when the legislature is in session (December–May). The 

building is primarily unoccupied on the weekends during nonsession times but may be 

occupied on weekends when the legislature is in session. 

Building Envelope

The building architecture reflects the terrain of the islands, with an exterior composed of 

concrete construction, and a specialized roof. The building has a rectangular footprint with a 

central courtyard and large underground parking structure. The fenestration includes fixedpane windows all around the perimeter of the building. Exterior corridors surround the 

perimeter of the courtyard and connect the legislative offices on common floors. 

Heating, Ventilation, and Air Conditioning

The HVAC system is a CAV system but is scheduled to be replaced with a VAV system. The 

HVAC system is scheduled to operate between 7:00 a.m. and 6:00 p.m. on weekdays and is

typically scheduled to be off at night and on weekends when the legislature is not in session. 

However, the HVAC system may be operated 24 hours per day seven days per week when the 

legislature is in session. 
14 

Cooling Plant

The chilled water system includes three chillers—two 380-ton variable-speed rotary hermetic 

centrifugal water-cooled chillers and one 250-ton screw chiller for after-hour usage. There are 

three cooling towers controlled by variable-frequency drives (VFDs) to cool the condenser 

water. Chillers and cooling towers are operated between 6:00 a.m. and 4:30 p.m. on the 

weekdays and are typically off at night and on weekends when the legislature is not in 

session. However, the cooling plant may be operated 24 hours per day seven days per week 

when the legislature is in session. Chilled water is distributed through variable-speed pumping 

and premium efficiency pump motors. 

Domestic Hot Water

DHW is supplied by distributed electric hot water tanks. 

Building Automation System

The HVAC systems, including AHUs, chillers, and pumps, are controlled by a WEBCtrl by 

Automated Logic BAS. The BAS is currently located on a terminal in the facilities office, 

which is located in an adjacent building. Schedules and set points for the various pieces of 

equipment are implemented through the BAS. 

Lighting

A majority of the fixtures use T-8 fluorescent lamps with electronic ballasts. However, some 

less efficient metal halide and halogen lamps were observed in the auditoriums and exterior 

hallways. 

Plug Loads

The primary electrical plug load in the facility consists of the office equipment. The main 

office equipment loads are associated with the desktop computer workstations, printers, and 

copiers. There are a few small data closets throughout the building, but no major data centers. 
15 

CLIMATE DATA

The city of Itoman, Okinawa Prefecture, Japan, is at an elevation of 9 feet above sea level, 

and its latitude and longitude are approximately 26.07o north, 127.39o east, respectively. The 

climate in Itoman features some variations in temperature from season to season with 

consistently high humidity and precipitation year round. 

The Hawaii State Capitol building is located in Honolulu, Hawaii. The city is at an elevation 

of 24 feet above sea level, and its latitude and longitude are approximately 21.18o north, 

157.51o west, respectively. The climate in Honolulu features small variations in temperature 

from season to season with moderate humidity and precipitation year round. 

On average, Honolulu experiences slightly higher average temperature and therefore more 

cooling degree days2 than Itoman. However, Itoman experiences higher humidity levels and 

significantly more precipitation. Table 5 shows the 2011 monthly weather summary for both 

Itoman and Honolulu. 

Table 5. 2011 Historic Weather Summary3

Itoman, Okinawa Prefecture, Japan Honolulu, Hawaii, USA

2011

Average 

Precip. 

(inches)

Average 

Temp. 

(F)

Cooling 

Degree 

Days

(65°F)

Average 

Dew 

Point 

(F)

Average 

Precip. 

(inches)

Average 

Temp. 

(F)

Cooling 

Degree 

Days

(65°F)

Average 

Dew 

Point 

(F)

Jan 4.9 59 0 47 2.8 74 271 63

Feb 5.0 64 35 54 0.5 75 288 66

Mar 6.3 63 28 50 1.1 77 366 64

Apr 6.5 69 107 57 1.7 78 376 66

May 9.9 75 314 69 2.1 79 435 66

Jun 11.0 82 504 77 1.3 80 449 67

Jul 7.0 84 578 77 0.3 81 489 67

Aug 10.6 83 562 76 0.0 82 518 67

Sep 6.9 82 514 73 0.1 82 499 67

Oct 6.5 78 397 69 0.0 81 490 67

Nov 5.2 75 301 66 0.9 79 425 65

Dec 4.4 66 59 54 0.8 77 359 65

Annual 84.2 73 3399 64 11.7 79 4965 66

Figure 3 shows the annual hourly typical meteorological year (TMY) plotted on the 

psychrometric chart. These charts show the higher concentration of humidity and wider 

 

2 Degree day is a quantitative index of the demand for energy to heat or cool buildings. A mean daily 

temperature of 65°F is the base for both heating and cooling degree day computations. Source: 

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/cdus/degree_days/ddayexp.shtml

3 Weather Underground Inc. (2012). Accessed October 29, 2012: http://www.wunderground.com. 
16 

variation of temperature in Itoman, in contrast to the higher concentration of temperature and 

wider variation of humidity in Honolulu. High humidity levels and temperatures in both cities

create a high cooling demand, which requires mechanical cooling to achieve comfortable 

working conditions for a majority of hours throughout the year. 

Figure 3. Annual weather data plotted on a psychrometric chart: Itoman (top), Honolulu 

(bottom) 
17 

UTILITY DATA

The electric provider at Itoman City Hall is Okinawa Electric Power Company Inc. (OEPC or 

OKIDEN). The annual electricity use for the Itoman City Hall in 2011 was 1,777,604 kWh at 

a cost of $465,848 (39,597,062 Yen). The energy use intensity (EUI) in 2011 was 

approximately 37 kBtu/ft2 (115 kWh/m2), which is significantly lower than the average for an 

office building in a semitropical climate according to the commercial building energy 

consumption survey (CBECS). The rate schedule is not a simple blended rate; in 2011 it 

included a ratcheting demand charge of approximately $6.41/kW, a time-of-use electricity 

charge with a daytime rate of $0.27 between 6 a.m. and 11p.m. and a nighttime rate of $0.11 

between 11 p.m. and 6 a.m., and additional taxes/fees. Figure 4 shows the electricity usage, 

rate trends, and cost allocations. The electricity usage of the Itoman City Hall building is 

heavily dependent on the weather conditions. Baseline energy consumption is approximately 

100,000 kWh per month and increases to 230,000 kWh per month during the summer months, 

a 130% increase. The electricity usage follows a trend very similar to the cooling degree days 

(CDD) which means that the building cooling system is correctly varying with load. The 

nighttime electrical cost is only 3% of the annual cost, which may be an indication that the 

thermal storage system is not being utilized at its full potential. 

The electric provider at Hawaii State Capitol building is Hawaiian Electric Company 

(HECO). The current rate schedule is a Schedule P, for large power services greater than 300

kW. The annual electricity use for the Hawaii State Capitol building in 2011 was 4,765,600 

kWh at a cost of $1,397,433. The EUI in 2011 was approximately 86 kBtu/ft2

 (271 kWh/m2),

which is average for an office building in a semitropical climate according to the CBECS. The 

rate schedule is not a simple blended rate; it includes a customer charge of $350/month, a 

ratcheting demand charge of $19.37/kW, an electricity charge of $0.28/kWh in 2011, and 

additional taxes/fees. Figure 5 shows the electricity usage, rate trends, and cost allocations. 

The electricity usage of the Hawaii State Capitol building is heavily dependent on the 

occupancy schedule of the legislature. When the legislature is in session from December 

through May, the electricity usage is approximately 27% higher. During the nonsession 

months, June through November, the building consumes a relatively constant amount of 

electricity, regardless of outdoor air conditions. This may be an indication that the chilled 

water system is not varying with load. Upon further investigation of the 2011 hourly trend 

data provided by NORESCO, it was determined that the VFDs on the chilled water system 

were operating at full speed when commanded on. Retrocommissioning of the chilled water 

system is recommended. 
18 

Figure 4. Itoman City Hall electricity usage (top), rates (middle), cost allocation (bottom) 
19 

Figure 5. Hawaii State Capitol electricity usage (top), rates (middle), cost allocation (bottom) 
20 

BEST PRACTICES AND OBSERVATIONS

50% Design Guide Recommendations

The following list is a summary of recommendations from the American Society of Heating, 

Refrigerating, and Air-Conditioning Engineers (ASHRAE) 50% Advanced Energy Design 

Guide (AEDG) for Small to Medium Office Buildings. This guide outlines design and 

operating strategies for buildings to achieve 50% energy savings toward net zero. The 

following recommendations are typically considered for new construction, but several of the 

concepts can be used in retrofit opportunities. 

Integrated Design Process

Create an integrated design team as early as possible, typically during the pre-schematic 

design phase. Include energy and water efficiency performance in construction contract or 

owner’s project requirements (OPR) and include energy use intensity targets (kBtu/ft2 or 

kWh/m2). Incorporate energy and daylight modeling during the design phase from specialized 

consultants. Make sure to conduct detailed training for building owners and operators. Utilize

enhanced commissioning efforts as well as measurement and verification of performance. 

Consider using award fee incentive to ensure quality and performance goals are met. 

Site Selection

Consider sustainability options when selecting a site, such as land reuse, recycled materials, 

and public transportation. Orient the building with the long axis parallel to east-west axis for 

good daylighting. Consider a narrow footprint to allow deeper penetration of daylight and 

natural ventilation. Minimize ecological impacts (e.g., rainwater runoff). 

Envelope

Reduce thermal transmittance with strategies such as continuous insulation and mitigating

thermal bridging. Control solar gains with shading devices (east, west, and south facades). 

Minimize window areas on east and west facades with a whole building target of 20%-40% 

window-to-wall ratio. Reduce infiltration with strategies such as positive internal pressure and 

vestibule entrances. Design the roof surface to have high reflectance (greater than 0.7), high 

emissivity (greater than 0.86), and high solar reflectance index (SRI) (greater than 0.85).

Specify fenestration with a low U-value (less than 2.9 W/m2

-K or 0.51 BTU/hr-ft2-

o

F) and a 

low solar heat gain coefficient (SHGC) (less than 0.26). Utilize high thermal mass

construction materials to reduce the impacts of peak temperatures.

Figure 6. Example cross section of exterior wall with continuous insulation 

Photo by Pat Corkery, NREL/PIX 16763 
21 

HVAC

Design HVAC zoning to accommodate different space orientations and use types. Consider 

radiant cooling with tight envelope and good humidity controls or VAV systems with variable 

speed drives to reduce fan energy. Utilize central building automation systems to enable 

controls with scheduling and setbacks for applicable systems. Utilize high efficiency air 

delivery systems, such as dedicated outside air systems (DOAS) with energy recovery, 

demand control ventilation, and under-floor air distribution. Install equipment with the highest 

efficiency available, such as premium efficiency motors and cogged or synchronous V-belts. 

Consider multistage chillers with high full load energy efficiency ratio (EER) (greater than 

10) and high integrated part load value (IPLV) (greater than 12.75). Consider water source 

heat pumps (WSHP) with high full load EER (greater than 15) and high part load EER 

(greater than 17.6). Utilize variable-flow pumping for all applicable chilled water distribution. 

Figure 7. Example of premium efficiency pump motor 

Photo by Warren Gretz, NREL/PIX 01208 

Service Hot Water

Utilize high efficiency service hot water heaters (greater than 90%). Ensure insulated service 

hot water distribution pipes. Consider high efficiency heat pump water heaters to 

simultaneously heat water and cool the surrounding area (greater than 3.0 coefficient of 

performance [COP]). Consider using on-demand hot water heaters to reduce tank losses and 

distribution pipe losses. 

Figure 8. Example of heat pump service water heater 

Photo by NREL/PIX 20289 
22 

Lighting

Design the lighting system to have a low lighting power density (LPD) (less than 8.1 watts

[W]/m2 or 0.75 W/ft2). Utilize high-efficacy lamps (greater than 90 lumens/W). Consider 

high-performance lensed luminaires and reflectors. Utilize super T8 and T5 linear fluorescent 

lighting with low ballast factor (BF) electronic ballasts (less than 0.77). Consider LED lights 

for displays, exterior, and parking lighting. Utilize occupancy and vacancy sensors in all 

applicable spaces, such as private offices, open offices, restrooms, conference rooms, and 

break rooms. Consider high color temperature lighting (3,700–4,100 kelvins [K]) for higher 

perceived brightness. Design the egress lighting to have a low LPD (less than 0.81 W/m2 or 

0.075 W/ft2). Consider occupancy sensor egress lighting, but consult building codes for 

compliance requirements. Design the exterior lighting system to have a low LPD (less than 

1.1 W/m2 

or 0.1 W/ft2) and consider timer controls. 

Daylighting

Design the building to allow diffuse light through the north façade and redirect the direct light 

into the space through the south façade. Utilize shading devices on east, west, and south 

façades. Avoid direct solar heat gain and direct solar glare with tints, light shelves, or louvers.

Design daylighting windows to have high visual transmittance (VT), low SHGC, and a high 

VT/SHGC ratio (greater than 1.1). Design view windows to have low VT to avoid glare and 

low SHGC. Utilize dimming ballasts on electrical lighting with photocell controls, preferably 

with electronic program start ballasts and continuous dimming controls. Design space walls 

and ceilings to have high internal surface reflectance (greater than 80% reflectance).

Figure 9. Example of window shading (left) and sunlight redirection device (right) 

Photos by Dennis Schroeder NREL/PIX 19798 and 17900 

Plug Loads

Design office spaces to have a low equipment power density (EPD) (less than 5.92 W/m2

 or 

0.55 W/ft2). Consider low energy computing options, such as laptops or low-energy desktops. 

Require procurement standards to include the ENERGY STAR label for all computers, 

equipment, and appliances. Enable computer power management settings on all computers to 

“Turn off monitor” after 5 minutes of nonuse, “System standby” after 10 minutes of nonuse, 

and “Turn off hard disk” set at 10 minutes. Remove vending machine advertising lighting and 

install misers on all applicable machines. Remove personal printers and consider setting a 

standard to utilize network printing with 60 occupants per printer. Consider using plug load 

controls (occupancy, timers) to turn off devices during unoccupied periods. Discourage the 

use of thermal comfort devices, such as fans or heaters. 
23 

Figure 10. Example of various plug load control devices 

Photo by Chad Labato, NREL

Water Efficiency

Consider waterless or high efficiency fixtures, such as toilets (less than 1.3 gallons/flush), 

urinals (less than 0.5 gallons/flush), faucets (less than 1.5 gallons/minute), and shower heads 

(less than 2.0 gallons/minute). Minimize cooling tower blow down with controls and chemical 

treatments. Utilize climate-appropriate landscape and consider opportunities for water reuse. 

Figure 11. Example of waterless urinal 

Photo by NREL/PIX 12313 

On-site Generation

Consider installing a PV system, either roof-mounted, ground-mounted, or buildingintegrated. Utilize solar water heating (non-freeze-protected) for service hot water. Consider 

other renewable energy systems such as fuel cells, biomass, and wind for on-site electricity 

generation. 

Figure 12. Example of rooftop photovoltaic system 

Photo by Dennis Schroeder, NREL/PIX 21582 
24 

Summary of Best Practices Observed

Several energy efficiency, water efficiency, and renewable energy best practices were 

observed during the site visits to Itoman City Hall building and Hawaii State Capitol building. 

Table 6 shows a summary of the best practices observed during the building evaluations, with 

those found at both sites listed in the center column. 

Table 6. Summary of Best Practices Observed During the Building Evaluations

Itoman City Hall Building Best Practices Observed at 

Both Sites

Hawaii State Capitol 

Building

Energy saving temperature set

points (27oC, 80oF)

Knowledgeable, proactive, 

and competent facilities staff

Cooling tower fan 

sequencing 

Central lighting controls for 

scheduling 

Good preventative 

maintenance schedules

Premium efficiency 

motors 

No cubicle walls allows better 

views, ventilation, and daylight 

penetration 

De-lamped lighting fixtures 

in many spaces 

Lighting occupancy 

sensors in private 

offices and restrooms

Ice storage system to reduce 

peak daytime loads 

Good shading on exterior of 

building 

Bi-level light 

switching

Use of rainwater for toilets and 

urinals

LCD computer monitors Vending machine 

misers

Operable windows with crossventilation Central building automation 

system

Energy awareness and 

education campaign 

Air-side economizer based on 

outdoor air temperature 

T8 and CFL lighting Low-flow water 

fixtures

Vestibule doors at entrances Window tint to reduce solar 

heat gain 

Demand control 

ventilation 

Permeable paving in parking lot Electronic controls

195-kW PV system Well-insulated pipes 

Demand response High thermal mass building

Variable speed drives

LED exit signs
25 

Figure 13. Itoman City Hall building photovoltaic system (left) and cold brine storage (right) 

Photos by Ian Metzger, NREL

Figure 14. Energy awareness and education campaign observed at the Hawaii State Capitol 

building 

Photos by Ian Metzger, NREL
26 

Energy Efficiency, Water Efficiency, and Renewable Energy Opportunities

Although several best practices were observed, there were also several energy efficiency, 

water efficiency, and renewable energy opportunities observed during the site visits to the 

Itoman City Hall building and Hawaii State Capitol building. Table 7 shows a summary of the 

opportunities observed during the building evaluations, with the opportunities found at both 

sites listed in the center column. Detailed descriptions of the current conditions, 

recommended actions, and energy/cost savings analysis can be found in Appendix A for the 

Itoman City Hall building and Appendix B for the Hawaii State Capitol building. 

Table 7. Summary of Opportunities Observed During the Building Evaluations

Itoman City Hall Building Opportunities Observed at Both 

Sites

Hawaii State Capitol 

Building

De-lamp overilluminated 

spaces

Install cogged V-belts on all fan 

drives

Implement computer 

power management

Install premium efficiency 

motors on pumps 

Convert CAV distribution to 

VAV system

Procure ENERGY STAR

refrigerators

Investigate replacing large 

chillers with staging units

Reduce ventilation rates to 

ASHRAE 62.1-2010 levels

Install timers on plug 

loads

Replace T12 lighting with 

T8 lamps and electronic 

ballasts

Replace desktop computers with 

laptops (or low-energy desktops) 

during normal replacement cycle

Install PV system on 

southeast lawn 

Install low-flow aerators on 

faucets

Consolidate the number of 

networked printers

Consider a solar water 

heating system 

 Replace metal halide, halogen, 

and CFL lighting with LEDs 

 Install lighting occupancy 

sensors 
27 

Figure 15. Standard V-belt fan motor drive at Itoman City Hall building 

Photos by Ian Metzger, NREL

Figure 16. Nighttime exterior metal halide lighting at Hawaii State Capitol building 

Photo by Ian Metzger, NREL
28 

APPENDIX A: DETAILED ENERGY ANALYSIS FOR ITOMAN 

CITY HALL BUILDING

Building Energy Modeling

Building energy modeling was used to determine the energy use characteristics of the building 

and to calculate energy and energy cost savings from various energy conservation measures

(ECMs) analyzed for the project. eQUEST was selected as the building simulation software 

tool to perform the energy modeling of this site. eQUEST is a commercially available 

interface for the DOE-2 hourly building energy simulation program originally developed by 

DOE. The program is capable of evaluating energy and energy cost savings that can be 

achieved by applying ECMs such as improved envelope components, passive heating and 

cooling strategies, lighting system improvements, and HVAC system improvements. The 

software is commonly used to analyze new construction buildings and building retrofits. 

eQUEST requires a detailed description of the building envelope (for thermal and optical 

properties), internal loads, operating schedules, lighting, HVAC system requirements, and 

utility rate schedules. The major benefits of eQUEST include the ease of defining building 

geometry, space characteristics, schedules, and HVAC systems, and the ability to run

parametric analyses to study design and retrofit options. Another major benefit of eQUEST is 

the relatively short simulation run times. 

An eQUEST energy model of the Itoman City Hall building was created. The existing 

operating condition of lighting, equipment, and HVAC systems was modeled, including 

current operating schedules and, as much as possible, equipment operational characteristics 

determined from discussion with the facilities team. 

A graphical representation of the building energy model developed in eQUEST is shown in 

Figure 17. The geometry of the buildings was simplified for modeling purposes to accurately 

simulate energy transfer through all surfaces in the building.
29 

Figure 17. Itoman City Hall building eQUEST model representation 

Figure 18 presents the eQUEST output for the calibrated baseline energy model for the 

Itoman City Hall building. The energy model was calibrated to within 5% of the actual energy 

use of the building. As shown, cooling energy is the largest energy consumer followed by 

lighting, plug loads (miscellaneous equipment), and ventilation. 

Figure 18. Itoman City Hall building eQUEST model calibrated results for annual energy use
30 

Energy Efficiency and Renewable Energy Opportunities

This section describes the various energy efficiency, water conservation, and renewable 

energy opportunities observed during the site visit of Itoman City Hall building. The 

opportunities are organized by building energy system type and describe the current 

conditions, recommended actions, and energy/cost savings analysis. 

HVAC Energy Conservation Measures

Replace Standard V-Belts with Cogged V-Belts

Current Condition: The assessment team only observed a small sample of the AHUs but 

found standard V-belts on most of the HVAC fan drives. These motors are asynchronous 

induction motors. The motors are currently operated for an estimated run time of 2,346 hours 

per year. The typical AHU had a 10-horsepower (Hp) motor and 89.5% efficiency. Each floor 

was assumed to have to air handlers, and all were assumed to be identical. 

Recommended Action: Replace all of the standard V-belts with cogged V-belts. Cogged 

V-belts have slots that run perpendicular to the belt’s length, which reduce the bending 

resistance of the belt. This design reduces slip and increases the overall efficiency of the 

motor-belt-fan drive. 

Figure 19. Cogged V-belt (left) and standard V-belt (right) 

Photo by Caleb Rockenbaugh, NREL 

Cogged V-belts can be used with the same pulleys as equivalent rated V-belts. They run 

cooler, last longer, and have an efficiency that is on the order of 2%–3% higher than standard 

V-belts. The belts associated with the largest motors and the motors that are run closest to full 

load should be given priority when making replacements. 
31 

Table 8. Energy and Cost Savings Summary for Replacing V-Belts

Energy and Cost Savings

Electricity Savings (kWh/yr) 5,189

Cost Savings ($/yr) $1,430

Implementation Costs ($) $2,210

Simple Payback (years) 1.5

CO2 Savings (metric tons/yr) 4.1

Assumptions:

• Assumed two air handlers per floor and all are identical

• Assumed standard efficiency for all motors because nameplates did not contain efficiency

• Savings are calculated using a 3% efficiency improvement from the cogged V-belt 

• Assumed the motor load to be 75% 

• Estimated labor costs at $75/hr x 2 hrs/motor 

• Belt costs were estimated at $20/motor

• Energy savings take into account interactions with the cooling systems 

• A 30% contingency was added to the implementation cost 

Reduce Ventilation Rates to Meet Current Standards

Current Condition: The Itoman City Hall building was originally designed for ventilation 

rates that are set to approximately 20 cubic feet per minute (cfm) per person or higher. In the 

past 10 years since the building was designed, ventilation standards have reduced the amount 

of ventilation air required. It is estimated that the current percentage of outside air is 

approximately 15% higher than is required by 2012 ventilation standards. 

Recommended Action: Reduce ventilation airflow rates to current ventilation standards. It 

will be necessary to carry out a more detailed engineering analysis to determine required rates 

for each AHU. 

Implementing this ECM includes:

• Carrying out detailed ventilation rate calculations for each AHU

• Rebalancing outside airflow dampers at each AHU. 
32 

Table 9. Energy and Cost Savings Summary for Reducing Ventilation Rates

Energy and Cost Savings

Electricity Savings (kWh/yr) 17,916

Cost Savings ($/yr) $5,182

Implementation Costs ($) $31,200

Simple Payback (years) 6.0

CO2 Savings (metric tons/yr) 14.2

Assumptions: 

• The eQUEST energy model was used to estimate the savings from reducing the 

ventilation rates.

• The ventilation rate was assumed to be reduced by 15%. 

• The design of the ventilation rates was assumed to be 40 hours x $200/hr, which totals 

$8,000. 

• The labor time to implement reducing the ventilation rates was assumed to take 120 hours 

x $100/hr, which totals $12,000. 

• Commissioning the AHUs was assumed to take 40 hours x $100/hr, which totals $4,000. 

• A 30% contingency was added to the overall cost. 

Convert CAV Distribution to VAV 

Current Condition: Currently a majority of the spaces at the Itoman City Hall building

are served by constant air volume systems. In a CAV system, variations in the thermal 

requirements of the building are satisfied by varying the temperature of a constant volume of 

air delivered to the building. Alternatively, a variable air volume system can adjust the flow 

rate of conditioned air to the space, saving significant fan energy as well as cooling energy. 

Recommended Action: Retrofit the CAV systems at the Itoman City Hall building to a 

VAV system. This will require converting each CAV box to a VAV box and installing 

VFDs on the supply and return fans of the air-handling units (AHUs). Each VAV box should 

be specified with an electronic damper actuator and an electronic temperature and relative 

humidity (temp/RH) sensor that are controlled through the BAS. The occupants should not be 

given the ability to modify the temp/RH set points. VAV box damper position should be 

connected to the BAS. 
33 

Table 10. Energy and Cost Savings Summary for Converting CAV to VAV System

Energy and Cost Savings

Electricity Savings (kWh/yr) 531,573

Cost Savings ($/yr) $141,384

Implementation Costs ($) $1,687,966

Simple Payback (years) 11.9

CO2 Savings (metric tons/yr) 419.9

Assumptions: 

• The eQUEST energy model was used to calculate the energy and cost savings for 

installing a VAV system that serves the Itoman City Hall building. 

• The total area served by the proposed VAV system is estimated to be 166,130 ft2. 

• The building is estimated to have 17 AHUs, based on each AHU serving 10,000 ft2 of 

floor area. 

• It was assumed that 17 air handlers would have to be converted from CAV to VAV and 

two VFDs are required per air handler (supply and return).

o 34 VFDs will be needed at $2,000 each, which totals $68,000. 

• It was assumed that each VAV box could cover 500 sq ft, resulting in an estimated 333

VAV boxes.

• The cost of each VAV box was estimated to be $695 per box, totaling $231,435 for all 

333 VAV boxes. 

• The labor cost associated with installing the VAV boxes was estimated to be $2,000 per 

box, totaling $666,000 for all 333 VAV boxes.

• The cost of the control points at each VAV box was estimated to be $1,000 per point, 

totaling 333,000. 

• A 30% contingency was added to the final cost.

Install Premium Efficiency Motors on all HVAC Fan and Pump Motors

Current Condition: The assessment team observed standard efficiency motors driving the 

majority of HVAC fans/pumps. These motors are asynchronous induction motors; the 

majority have open, drip-proof enclosures and efficiency ratings below the National Electrical 

Manufacturers Association (NEMA) Premium efficiency rating. The motors are currently 

operated for an estimated run time of 2,346 hours annually. It is good practice to install 

premium efficiency motors when replacing a motor because the slight cost increase is justified 

by significant savings in energy cost, which is especially true of larger motors that have long 

operating hours. The following motors were investigated for replacement with NEMA 

Premium efficiency motors: 
34 

Table 11. Existing Motor Inventory

Existing Motors Quantity Horsepower

Standard 

Efficiency

Premium 

Efficiency

AHU Fan Motors 10 10 89.50% 92.50%

Chilled Water Pumps 3 & 4 2 15 90.50% 93.10%

Chilled Water Pump 5 1 20 91.50% 93.50%

Recommended Action: Replace all of the standard efficiency, three-phase, asynchronous 

induction motors feeding HVAC fans/pumps. Specify premium efficiency motors with similar 

enclosure type, speed, mounting, and electrical input. 

The Copper Development Association recently introduced a line of ultra-efficient motors into 

the U.S. market, which exceed NEMA Premium standards. These motors utilize a die-cast 

copper rotor, which reduces the energy requirements of the motor and allows it to run cooler. 

The motor also features an improved heat-dissipation system and new low-friction bearings, 

both of which help extend the life of the motor. The motor also has a smaller weight and size 

compared to the standard NEMA Premium efficiency motors. The motors are showing 

efficiency improvements on the order of 3%–10% higher than current NEMA Premium 

standards.

Table 12. Energy and Cost Savings Summary for Installing Premium Efficiency Motors

Energy and Cost Savings

Electricity Savings (kWh/yr) 8,101

Cost Savings ($/yr) $2,413

Implementation Costs ($) $23,332

Simple Payback (years) 9.7

CO2 Savings (metric tons/yr) 6.4

Assumptions:

• Assumed two air handlers per floor and all are identical

• Assumed standard efficiency for all motors because nameplates did not contain efficiency

• Calculated energy savings using the MotorMaster+ International software tool 

• Assumed the existing motor load was 75% and the proposed motor load was 75% 

• Estimated labor costs at $75/hr x 2 hrs/motor 

• Estimated motor costs using the MotorMaster database

• Energy savings take into account interactions with the cooling systems 

• Added a 30% contingency to the overall cost 
35 

Additional HVAC ECMs

Investigate Corrosion-Prevention Options for Chillers

Some of the condensing units located on the rooftop were showing signs of corrosion. The 

high rate of corrosion may be due to the high salt content in the humid ocean air. Further 

investigation is required to test corrosion-resistant coating for rooftop equipment. 

Consider Replacing Large Chillers with Modular Chillers

Currently, there are three large air-cooled chillers that serve the Itoman City Hall building: 

one 300-kW air-cooled chiller and two 245-kW air-cooled brine chillers for thermal storage. 

The two 245-kW brine chillers that are used for thermal storage typically operate at full load 

when making ice during the night. The 300-kW chiller is typically operating during the day to 

supplement the cooling provided by the thermal storage system. The 300-kW chiller typically 

operates at part load, which results in reduced chiller efficiency. Modular chillers have 

multiple compressors and operate at much higher efficiencies when part loaded. 

Lighting Energy Conservation Measures

De-lamp Overilluminated Spaces

Current Condition: The assessment team observed several spaces that were illuminated over 

the Illuminating Engineering Society’s (IES’s) recommended levels for office space types.

The table below shows the IES-recommended light levels for typical space types. 

Table 13. IES-Recommended Light Levels by Task Area 

Recommended Light Levels 

Task Area Foot-candles

Corridors/Stairways/Restrooms 10–20

Storage Rooms 10–50

Conference Rooms 20–50

General Offices 50–100

Drafting/Accounting 100–200

Areas with VDTs 75

Classrooms 50–75

Cafeterias 50

Gymnasiums 30–50

Merchandising 30–150

Manufacturing Assembly 50–500

Parking Areas (uncovered) 1–2

Recommended Action: Using a light meter, de-lamp fixtures in overilluminated spaces until 

the light levels reach an acceptable range. Educate staff about the recommended light levels and 

train facilities staff not to “fix” de-lamped fixtures in the future.
36 

Table 14. Energy and Cost Savings Summary for De-Lamping 

Energy and Cost Savings

Electricity Savings (kWh/yr) 6,925

Cost Savings ($/yr) $1,981

Implementation Costs ($) $3,413

Simple Payback (years) 1.7

Annual CO2 Savings (metric tons/yr) 5.5

Assumptions:

• Total number of fixtures de-lamped was estimated to be 70. 

• Labor costs were estimated at $75/hr x 30 minutes/fixture. 

• Energy savings take into account interactions with the cooling systems. 

• A 30% contingency was added to the implementation cost. 

Install Occupancy Sensors in Restrooms 

Current Condition: The assessment team observed some spaces where occupancy sensors 

could be applicable that did not already have them installed. The assessment team observed 

most spaces already had occupancy sensors; approximately 16 restrooms did not. These 

spaces had approximately 80, one-lamp, 32-W, T8 fixtures with a total load of 2.6 kW and an 

estimated operational time of 2,920 hours per year. 

Figure 20. Typical wall-switch lighting occupancy sensor

Photo by Dennis Schroeder, NREL/PIX 19323 
37 

Figure 21. Typical ceiling-mounted lighting occupancy sensor coverage (top) and application 

(bottom) 

Illustration by Josh Bauer, NREL; photo by NREL/PIX 19322 

Recommended Action: Install passive electronic sensors to automatically activate and 

deactivate space-lighting circuits based on occupancy. There are two commonly used sensors: 

infrared and ultrasonic. Infrared sensors detect occupants by sensing changes in heat patterns 

as occupants move, while ultrasonic sensors detect physical movement. The type and location 

of each sensor must be carefully selected for each individual room layout and expected 

activity. In many instances, a simple wall-switch replacement is adequate. In other cases, a 

ceiling-mount sensor or wall-mount sensor may provide better coverage. In rooms with 

multiple lighting circuits or devices, multipole power packs and auxiliary relays can be 

configured to operate from a single sensor head. In larger spaces, multiple sensors can be 

wired in parallel to keep all lights on if any one sensor is triggered. This measure will not 

reduce peak demand but will reduce annual energy consumption. 
38 

Table 15. Energy and Cost Savings Summary for Installing Occupancy Sensors

Energy and Cost Savings

Electricity Savings (kWh/yr) 1,739

Cost Savings ($/yr) $468

Implementation Costs ($) $6,032

Simple Payback (years) 12.9

Annual CO2 Savings (metric tons/yr) 1.4

Assumptions:

• Percent reductions in operating time were estimated to be 30% due to occupancy sensors. 

• Labor costs were estimated at $100/hr x 2 hrs/sensor x 16 sensors.

• Occupancy sensor costs were estimated at $90/sensor x 16 sensors. 

• Energy savings take into account interactions with the cooling systems. 

• A 30% contingency was added to the implementation cost. 

Retrofit Metal Halide and Halogen Lighting with LED

Current Condition: The assessment team observed several metal halide and halogen lamps 

throughout the building. These lamps use significantly more than the LED-equivalent lamps. 

Table 16. Inventory and Location of Existing Lamps

200-Watt 

Metal 

Halide

100-Watt 

Metal 

Halide

130-

Watt 

Halogen

Building Façade 26

Interior Lobby 35

Second Floor Display Area 31

First and Fourth Floor Offices and Conference Room 35

Recommended Action: It is recommended that a comparison be conducted for replacement of 

lamps with a substitute ballast and lamp combination utilizing the existing fixture or that of a 

substitution luminaire (lamp, ballast, and/or fixture) with the existing voltage and circuitry. 

LED-equivalent lamp wattage and costs are described in the table below.

Table 17. LED-Equivalent Lamp Wattages and Costs

100-Watt 

Metal Halide

200-Watt Metal 

Halide

130-Watt 

Halogen

LED-Equivalent Wattage 35 Watts 52 Watts 22 Watts

Cost per Lamp $85.00 $350.00 $250.00 
39 

Table 18. Energy and Cost Savings Summary for LED Lighting

Energy and Cost Savings

Electricity Savings (kWh/yr) 45,982

Cost Savings ($/yr) $13,227

Implementation Costs ($) $55,361

Simple Payback (years) 4.2

CO2 Savings (metric tons/yr) 36.4

Assumptions:

• Labor rates were estimated at $75/hr.

• Labor time was estimated to be 30 minutes per halogen lamp and 2 hours per metal halide 

lamp.

• Cost savings does not include disposal costs. 

• Energy savings take into account interactions with the cooling systems for interior lamps. 

• A 30% contingency was added to the overall cost. 

Retrofit Remaining T12 Lighting with T8 Lighting and Electronic Ballasts

Current Condition: T-12 lamps with magnetic ballasts were observed scattered throughout 

the building. The assessment team identified 35 T-12 lamps in use at the time of the site visit

with an estimated total connected load of 1.4 kW and an estimated usage of 2,920 hours/year.

Recommended Action: On-site personnel should conduct a survey of the remaining lighting 

fixtures containing T-12 lamps and magnetic ballasts, and replace them with T-8 lamps and 

electronic ballasts. Ballasts should be specified to have a BF equal to or less than 0.9. 

Table 19. Energy and Cost Savings Summary for T8 Lighting

Energy and Cost Savings

Electricity Savings (kWh/yr) 1,989

Cost Savings ($/yr) $590

Implementation Costs ($) $6,143

Simple Payback (years) 10.4

CO2 Savings (metric tons/yr) 1.6

Assumptions:

• Labor rates were estimated at $100/hr.

• Labor time was estimated to be 2 hours per fixture. 

• Replacement costs were estimated to be $5 per lamp and $30 per fixture. 

• Cost savings does not include disposal costs. 
40 

• Energy savings take into account interactions with the cooling systems. 

• A 30% contingency was added to the overall cost. 

Plug-Load Energy Conservation Measures

Replace Desktop Computers with Low-Energy Desktops at Technology Refresh

Current Condition: The assessment team observed approximately 428 desktop computers in 

the building. Desktop computers use significantly more energy than low-energy desktops with 

the same processing capabilities. The typical office desktop computer has the following 

energy characteristics: Active/On Mode = 104 W, Suspended Mode = 15 W, Off Mode = 3 

W. 

Recommended Action: Convert all desktop computers to low-energy desktops. A typical 

low-energy desktop computer has the following energy characteristics: Active/On Mode = 19 

w, Suspended Mode = 3 w, Off Mode = 2 w. 

The analysis for an immediate replacement was found to have an unreasonable payback 

period; therefore, the desktops should be replaced incrementally at their scheduled time of 

replacement during the normal technology refresh cycle. The implementation cost incurred 

with this approach will be the incremental cost of purchasing a low-energy desktop instead of 

a standard desktop computer. 

Table 20. Energy and Cost Savings Summary for Low-Energy Desktops

Energy and Cost Savings

Electricity Savings (kWh/yr) 105,911

Cost Savings ($/yr) $30,878

Implementation Costs ($) $278,200

Simple Payback (years) 9.0

CO2 Savings (metric tons/yr) 83.9

Assumptions:

• Computers are replaced at the end of their useful life. Labor costs are not included for 

incremental replacements. 

• It was assumed that 95% of the computers were already using computer power 

management. 

• It was assumed that computers are not in use 5% of the time.

• Incremental cost for low-energy desktop compared to standard model is $500/computer. 

• Cost savings does not include disposal. 

• Energy savings take into account interactions with the cooling systems. 

• A 30% contingency was added to the overall cost. 
41 

Consolidate Network Printers

Current Condition: The assessment team observed approximately 67 networked printers and 

30 large multifunction printers (print, copy, scan, fax) in the building. These printers use a 

considerable amount of energy. Currently, the persons-to-printer ratio is about 13:1. 

Recommended Action: Consolidate the number of printers and remove unnecessary printers. 

The assessment team estimates that approximately half of the printers can be removed. 

Table 21. Energy and Cost Savings Summary for Low-Energy Desktops

Energy and Cost Savings

Electricity Savings (kWh/yr) 16,487

Cost Savings ($/yr) $5,959

Implementation Costs ($) $4,778

Simple Payback (years) 0.8

CO2 Savings (metric tons/yr) 13.1

Assumptions:

• It was assumed that 34 network printers and 15 multifunction printers are removed. 

• It was assumed that printers are in standby mode 95% of the time.

• Labor costs are estimated to be 1 hour per printer at $75/hour. 

• Cost savings does not include disposal or storage costs.

• Energy savings take into account interactions with the cooling systems. 

• A 30% contingency was added to the overall cost. 

Water Conservation Measures

Install Low-Flow Aerators on Faucets

Current Condition: The assessment team observed approximately 40 standard efficiency 

faucets in the building. The baseline water use characteristics were calculated assuming each 

male occupant washes his hands three times a day and each female occupant washes her 

hands four times a day. The faucets are standard water faucets with a rated flow rate of 2.5 

gallons per minute (gpm). 

Recommended Action: Install low-flow aerators on all existing standard faucets. The savings 

calculation was based on installing aerators on all faucets with 1.5-gpm flow rates.
42 

Table 22. Energy and Cost Savings Summary for Low-Flow Aerators

Energy and Cost Savings

Water Savings (Gal/yr) 85,167

Cost Savings ($/yr) $1,703

Implementation Costs ($) $3,120

Simple Payback (years) 1.8

CO2 Savings (metric tons/yr) 0.0

Assumptions:

• Assumed 200 male occupants and 200 female occupants 

• Assumed a wash duration of 0.17 minutes/wash 

• Assumed faucets are used 260 days per year 

• Estimated labor costs at $75/hr at 30 minutes per fixture 

• Estimated faucet aerator costs at $10/faucet x 40 faucets

• Energy savings were not taken into account 

• A 30% contingency was added to the overall cost 

Renewable Energy Measures

Investigate Performance Issues of Current PV System

The Itoman City Hall building currently has 195-kW of PV mounted on the roof and façade of 

the building. The system appears to be operating normally, as shown by the comparison to 

PVWatts simulation in the Table 23. The simulated annual electricity production has a percent 

difference of 9% when compared to the actual metered performance. A spot check of the 

inverter showed efficiencies in the low 90% range. Some maintenance issues have resulted

from the high salt content in the humid ocean air, which has caused corrosion. It is 

recommended that the PV and inverter performance continue to be monitored on a regular 

basis. 
43 

Table 23. Comparison of PV Performance Simulation to Actual

Month PVWatts Simulation (kWh) Actual (kWh)

1 8,777 11,771

2 10,444 12,739

3 15,909 15,449

4 17,490 16,103

5 18,604 15,398

6 17,220 19,618

7 19,348 15,029

8 19,410 10,222

9 17,884 12,110

10 13,687 8,301

11 10,775 13,463

12 10,720 15,145

Year 180,268 165,348
44 

APPENDIX B: DETAILED ENERGY ANALYSIS FOR HAWAII 

STATE CAPITOL BUILDING

Building Energy Modeling

Building energy modeling was used to determine the energy use characteristics of the building 

and to calculate energy and energy cost savings from various ECMs analyzed for the project. 

eQUEST was selected as the building simulation software tool to perform the energy 

modeling of this site. eQUEST is a commercially available interface for the DOE-2 hourly 

building energy simulation program originally developed by DOE. The program is capable of 

evaluating energy and energy cost savings that can be achieved by applying ECMs such as 

improved envelope components, passive heating and cooling strategies, lighting system 

improvements, and HVAC system improvements. The software is commonly used to analyze 

new construction buildings and building retrofits. eQUEST requires a detailed description of 

the building envelope (for thermal and optical properties), internal loads, operating schedules, 

lighting, HVAC system requirements, and utility rate schedules. The major benefits of 

eQUEST include the ease of defining building geometry, space characteristics, schedules, and 

HVAC systems, and the ability to run parametric analyses to study design and retrofit options. 

Another major benefit of eQUEST is the relatively short simulation run times. 

An eQUEST energy model of the Hawaii State Capitol building was created. The existing 

operating condition of lighting, equipment, and HVAC systems was modeled, including 

current operating schedules and, as much as possible, equipment operational characteristics 

determined from discussion with the facilities team. 

A graphical representation of the building energy model developed in eQUEST is shown in 

Figure 22. The geometry of the building was simplified for modeling purposes to accurately 

simulate energy transfer through all surfaces in the building.

Figure 22. Hawaii State Capitol building eQUEST model representation 

Figure 23 presents the eQUEST output for the calibrated baseline energy model for the 

Hawaii State Capitol building. The energy model was calibrated to within 5% of the actual 
45 

energy use of the building. As shown, lighting energy is the largest energy consumer followed 

by plug loads (miscellaneous equipment) and ventilation. 

Figure 23. Hawaii State Capitol building eQUEST model calibrated results for annual 

energy use
46 

Energy Efficiency and Renewable Energy Opportunities

This section describes the various energy efficiency, water conservation, and renewable 

energy opportunities observed during the site visit of the Hawaii State Capitol building. The 

opportunities are organized by building energy system type and describe the current 

conditions, recommended actions, and energy/cost savings analysis. 

Heating, Ventilation, and Air-Conditioning (HVAC) Energy Conservation 

Measures 

Replace Standard V-Belts with Cogged V-Belts

Current Condition: The assessment team only observed a small sample of the AHUs but 

found standard V-belts on most of the HVAC fan drives. These motors are asynchronous 

induction motors. The motors are currently operated for an estimated run time of 3,129 hours 

per year. 

Table 24. Observed Fan Drives with Standard V-belts

Fan Name Horsepower Efficiency

C-11B 3 88.5%

C-8 3.5 88.5%

C-5 15 82.0%

C-4 25 93.6%

C-13A 5 90.2%

C-13B 3 89.5%

C-6 10 92.4%

C-3 10 92.4%

Cooling Tower 1 50 95.0%

Cooling Tower 2 50 95.0%

Cooling Tower 3 50 95.0%

Recommended Action: Replace all of the standard V-belts with cogged V-belts. Cogged 

V-belts have slots that run perpendicular to the belt’s length, which reduce the bending 

resistance of the belt. This design reduces slip and increases the overall efficiency of the 

motor-belt-fan drive. 

Figure 24. Cogged V-belt (left) and standard V-belt (right) 

Photo by Caleb Rockenbaugh, NREL 
47 

Cogged V-belts can be used with the same pulleys as equivalent-rated V-belts. They run 

cooler, last longer, and have an efficiency that is on the order of 2%–3% higher than standard 

V-belts. The belts associated with the largest motors and the motors that are run closest to full 

load should be given priority when making replacements. 

Table 25. Energy and Cost Savings Summary for Replacing V-Belts

Energy and Cost Savings

Electricity Savings (kWh/yr) 9,542

Cost Savings ($/yr) $3,268

Implementation Costs ($) $2,214

Simple Payback (years) 0.7

CO2 Savings (metric tons/yr) 7.6

Assumptions:

• Savings are calculated using a 3% efficiency improvement from the cogged V-belt.

• The motor load was assumed to be 50%.

• Labor costs were estimated at $75/hr x 2 hrs/motor. 

• Belt costs were estimated at $20/motor. 

• Energy savings take into account interactions with the cooling systems.

• A 30% contingency was added to the implementation cost. 

Convert CAV Distribution to VAV 

Current Condition: Currently a majority of the spaces at the Hawaii State Capitol 

building are served by CAVs. In a CAV system, variations in the thermal requirements of 

the building are satisfied by varying the temperature of a constant volume of air delivered to 

the building. Alternatively, a VAV can adjust the flow rate of conditioned air to the space, 

saving significant fan energy as well as cooling energy. 

Recommended Action: Retrofit the CAV systems at the Hawaii State Capitol building to 

a VAV system. This will require converting each CAV box to a VAV box, and VFDs 

will need to be installed on the supply and return fans of the air-handling units. Each VAV 

box should be specified with an electronic damper actuator and an electronic temperature and 

relative humidity (temp/RH) sensor that are controlled through the BAS. The occupants 

should not be given the ability to modify the temp/RH set points. VAV box damper position 

should be connected to the BAS. 
48 

Table 26. Energy and Cost Savings Summary for Converting CAV to VAV System

Energy and Cost Savings

Electricity Savings (kWh/yr) 1,353,035

Cost Savings ($/yr) $407,404

Implementation Costs ($) $1,909,720

Simple Payback (years) 4.7

CO2 Savings (metric tons/yr) 1,083.3

Assumptions: 

• The eQUEST energy model was used to calculate the energy and cost savings for 

installing a VAV system that serves the Hawaii State Capitol building. 

• The total area served by the proposed VAV system is estimated to be 188,485 ft2. 

• The building is estimated to have 19 AHUs, based on each AHU serving 10,000 ft2 of 

floor area. 

• It was assumed that 19 air handlers would have to be converted from CAV to VAV and 

that two VFDs are required per air handler (supply and return).

o 38 VFDs will be needed at $2,000 each, which totals $76,000. 

• It was assumed that each VAV box could cover 500 sq ft, resulting in an estimated 377

VAV boxes.

• The cost of each VAV box was estimated to be $695 per box, totaling $262,015 for all 

377 VAV boxes. 

• The labor cost associated with installing the VAV boxes was estimated to be $2,000 per 

box, totaling $754,000 for all 377 VAV boxes.

• The cost of the control points at each VAV box were estimated to be $1,000 per point, 

totaling $377,000. 

• A 30% contingency was added to the final cost. 

Reduce Ventilation Rates to ASHRAE 62.1-2007 Levels

Current Condition: The Hawaii State Capitol building was originally designed for 

ventilation rates that are set to 20 cfm/person or higher. The ventilation rates were taken off 

the original construction. The current ventilation requirement for offices as specified by 

ASHRAE 62.1-2007 is 17 cfm/person. Therefore, the percentage of outside air required by 

ASHRAE is approximately 15% lower than the current ventilation rates. 

Recommended Action: Reduce ventilation airflow rates to ASHRAE 62.1-2007 required 

levels. It will be necessary to carry out a more detailed engineering analysis to determine 

required rates for each AHU using the ASHRAE ventilation rate procedure. Complying with 

ASHRAE 62.1-2007 should reduce ventilation airflow rates in the building by approximately 

15%. It is estimated that the minimum ventilation rate of the Hawaii State Capitol building 

could be set to 94,150 cfm. 
49 

Implementing this ECM includes: 

• Carrying out detailed ventilation rate calculations for each AHU using the ventilation rate 

procedure in ASHRAE 62.1-2007 

• Rebalancing outside airflow dampers at each AHU.

Table 27. Energy and Cost Savings Summary for Reducing Ventilation Rates

Energy and Cost Savings

Electricity Savings (kWh/yr) 48,955

Cost Savings ($/yr) $15,550

Implementation Costs ($) $31,200

Simple Payback (years) 2.0

CO2 Savings (metric tons/yr) 38.7

Assumptions: 

• The eQUEST energy model was used to estimate the savings from reducing the 

ventilation rates. 

• The ventilation rate was assumed to be reduced by 15%. 

• The design of the ventilation rates was assumed to be 40 hours x $200/hr, which totals 

$8,000. 

• The labor time to implement reducing the ventilation rates was assumed to take 120 hours 

$100/hr, which totals $12,000. 

• Commissioning the AHUs was assumed to take 40 hours x $100/hr, which totals $4,000. 

• A 30% contingency was added to the overall cost. 

Lighting Energy Conservation Measures

Install Occupancy Sensors in Conference Rooms and Offices 

Current Condition: The assessment team observed several spaces where occupancy sensors 

could be applicable that did not already have them installed. The assessment team observed 

that although most spaces already had occupancy sensors, approximately 12 offices and four 

conference rooms did not. These spaces had approximately 232, two-lamp, 25-W, T8 fixtures 

with a total load of 10.4 kW and an estimated operational time of 2,920 hours per year. 
50 

Figure 25. Typical wall-switch lighting occupancy sensor

Photo by NREL/PIX 19323 

Figure 26. Typical ceiling-mounted lighting occupancy sensor coverage (top) and application 

(bottom) 

Illustration by Joshua Bauer, NREL; photo by NREL/PIX 19322 
51 

Recommended Action: Install passive electronic sensors to automatically activate and 

deactivate space-lighting circuits based on occupancy. There are two commonly used sensors: 

infrared and ultrasonic. Infrared sensors detect occupants by sensing changes in heat patterns 

as occupants move, while ultrasonic sensors detect physical movement. The type and location 

of each sensor must be carefully selected for each individual room layout and expected 

activity. In many instances, a simple wall-switch replacement is adequate. In other cases a 

ceiling-mount sensor or wall-mount sensor may provide better coverage. In rooms with 

multiple lighting circuits or devices, multi-pole power packs and auxiliary relays can be 

configured to operate from a single sensor head. In larger spaces, multiple sensors can be 

wired in parallel to keep all lights on if any one sensor is triggered. This measure will not 

reduce peak demand but will reduce annual energy consumption.

Table 28. Energy and Cost Savings Summary for Installing Occupancy Sensors

Energy and Cost Savings

Electricity Savings (kWh/yr) 5,433

Cost Savings ($/yr) $1,521

Implementation Costs ($) $10,556

Simple Payback (years) 6.9

Annual CO2 Savings (metric tons/yr) 4.3

Assumptions:

• Percent reductions in operating time were estimated to be 15% due to occupancy sensors. 

• Labor costs were estimated at $100/hr x 2 hrs/sensor x 28 sensors.

• Occupancy sensor costs were estimated at $90/sensor x 28 sensors. 

• Energy savings take into account interactions with the cooling systems. 

• A 30% contingency was added to the implementation cost. 

Retrofit Metal Halide, Incandescent, and CFL Lighting with LED

Current Condition: The assessment team observed several metal halide, incandescent, and 

high-wattage CFL lamps throughout the building. Each light uses significantly more than the 

LED-equivalent lamps. 

Table 29. Inventory and Location of Existing Lamps

70-

Watt 

Metal 

Halide

175-

Watt 

Metal 

Halide

90-Watt 

Incandescent

150-

Watt 

Halogen

28-Watt 

CFL, 2-

Lamp 

Can 

Fixture

Exterior Corridors 551 18

House and Senate Chambers 430

Governor and Lt. Governor Offices 108 128

Auditorium 24 24
52 

Recommended Action: It is recommended that a comparison be conducted for replacement of 

lamps with a substitute ballast and lamp combination utilizing the existing fixture or that of a 

substitution luminaire (lamp, ballast, and/or fixture) with the existing voltage and circuitry. 

LED-equivalent lamp wattage and costs are described in the table below.

Table 30. LED-Equivalent Lamp Wattages and Costs

70-Watt 

Metal 

Halide

175-Watt 

Metal 

Halide

90-Watt 

Incandescent

150-

Watt 

Halogen

28-Watt 

CFL, 2-

Lamp Can

Fixture

LED-Equivalent Wattage 35 Watts 52 Watts 20 Watts 22 Watts 7 Watts

Cost per Lamp $85.00 $350.00 $60.00 $250.00 $40.00 

Table 31. Energy and Cost Savings Summary for LED Lighting

Energy and Cost Savings

Electricity Savings (kWh/yr) 200,110

Cost Savings ($/yr) $76,142

Implementation Costs ($) $415,249

Simple Payback (years) 5.5

CO2 Savings (metric tons/yr) 158.6

Assumptions:

• Labor rates were estimated at $75/hr. 

• Labor time was estimated to be 30 minutes per lamp, except labor for the chambers, which 

was estimated to be two hours per lamp. 

• Energy savings take into account interactions with the cooling systems for interior lamps 

• A 30% contingency was added to the overall cost. 

Plug-Load Energy Conservation Measures

Replace Refrigerators with ENERGY STAR Refrigerators

Current Condition: The assessment team observed approximately 26 large refrigerators in 

the building. The refrigerators were older models (top-mount freezer without through-thedoor ice) and were not ENERGY STAR rated. These refrigerators tend to use 20% more 

energy than newer ENERGY STAR models.

Recommended Action: Replace all older refrigerators with newer ENERGY STAR-rated 

refrigerators incrementally as the older models approach the end of their useful life.

The analysis for an immediate replacement was found to have an unreasonable payback 

period; therefore, the refrigerators should be replaced incrementally at their scheduled time of 
53 

replacement during the normal technology refresh cycle. The implementation cost incurred 

with this approach will be the incremental cost of purchasing an ENERGY STAR refrigerator 

instead of a standard refrigerator (approximately $30). 

Table 32. Energy and Cost Savings Summary for ENERGY STAR-Rated Refrigerators

Energy and Cost Savings

Electricity Savings (kWh/yr) 3,279

Cost Savings ($/yr) $918

Implementation Costs ($) $1,014

Simple Payback (years) 1.1

CO2 Savings (metric tons/yr) 2.6

Assumptions:

• Refrigerators are replaced at the end of their useful life. Labor costs are not included for 

incremental replacements. 

• Incremental costs of ENERGY STAR model compared to standard model was estimated 

to be $30. 

• O&M cost increase was estimated to be $0/year.

• Energy savings take into account interactions with the cooling systems. 

• A 30% contingency was added to the overall cost. 

Activate Computer Power Management

Current Condition: The facility has approximately 248 desktop computers. Many desktop 

computers are left running around the clock. There are several commercial computer power 

management software vendors, such as Surveyor, EZ Save, EZ GPO, Energy Saver Pro, and 

Night Watchman. These software programs are centrally administered programs that perform 

the following functions: (1) poll computers on a network to determine each monitor and 

computer’s power management settings; (2) generate reports on the result of the polling; (3) 

set appropriate power management settings on monitors and computers on the network; and 

(4) set appropriate screen-saver settings on monitors on the network so that users retain 

screen-saver images.

Recommended Action: Select a vendor to meet site-specific needs. Once a vendor is 

selected, the computer power management software should be centrally administered to all 

network computers. Although the assessment team cannot endorse a specific vendor, for this 

analysis, it is assumed the site would implement the Surveyor software program. 
54 

Table 33. Energy and Cost Savings Summary for Activating Computer Power Management

Energy and Cost Savings

Electricity Savings (kWh/yr) 49,784

Cost Savings ($/yr) $13,940

Implementation Costs ($) $12,545

Simple Payback (years) 2.4

CO2 Savings (metric tons/yr) 39.5

Assumptions:

• It was assumed 20% of the computers were already using computer power management. 

• It was assumed that computers are not in use 58% of the time.

• Labor costs were estimated at $75/hr x 0.25 hrs/computer x 248 computers. 

• Computer power management software costs were estimated at $13,940 with license 

renewal costs of $8,680/year. Management software costs were calculated from a general 

installation cost $5,000 and an additional $25 per computer for licenses. 

• Energy savings take into account interactions with the cooling systems. 

• A 30% contingency was added to the overall cost. 

Replace Desktop Computers with Low-Energy Desktops at Technology Refresh

Current Condition: The assessment team observed approximately 248 desktop computers in 

the building. Desktop computers use significantly more energy than low-energy desktops with 

the same processing capabilities. The typical office desktop computer has the following 

energy characteristics: active/on mode = 104 W, suspended mode = 15 W, off mode = 3 W. 

Recommended Action: Convert all desktop computers to low-energy desktops. A typical 

low-energy desktop computer has the following energy characteristics: active/on mode = 19 

W, suspended mode = 3 W, off mode = 2 W. 

The analysis for an immediate replacement was found to have an unreasonable payback 

period; therefore, the desktops should be replaced incrementally at their scheduled time of 

replacement during the normal technology refresh cycle. The implementation cost incurred 

with this approach will be the incremental cost of purchasing a low-energy desktop instead of 

a standard desktop computer. 
55 

Table 34. Energy and Cost Savings Summary for Low-Energy Desktops

Energy and Cost Savings

Electricity Savings (kWh/yr) 59,431

Cost Savings ($/yr) $21,051

Implementation Costs ($) $161,200

Simple Payback (years) 7.7

CO2 Savings (metric tons/yr) 47.1

Assumptions:

• Computers are replaced at the end of their useful life. Labor costs are not included for 

incremental replacements. 

• It was assumed that 20% of the computers were already using computer power 

management. 

• It was assumed that computers are not in use 58% of the time.

• Incremental cost for low-energy desktop compared to standard model is $500/computer. 

• Cost savings does not include disposal. 

• Energy savings take into account interactions with the cooling systems.

• A 30% contingency was added to the overall cost. 

Additional Plug-Load ECMs

Remove Personal Printers and Utilize Network Printers 

Considering the nature of work being done at the Hawaii State Capitol building, certain 

personal printers are required. Personal printers that are in place but not required for security 

or data-sensitivity reasons should be removed. Removal of each personal printer could result 

in a savings of 150 kWh/yr. 

Install Occupancy-Sensing Power Strips

Additional energy savings can be obtained by using occupancy-controlled power strips to 

power the under-cabinet fixtures and any additional equipment that employees might have at 

their desks. The occupancy sensors detect when the office is vacant and will shut off the 

equipment powered by the strip. 
56 

Figure 27. Plug-load occupancy sensor 

Photo by Caleb Rockenbaugh, NREL 

Typical occupancy-controlled power strips have five receptacles controlled by the occupancy 

sensor and three standard receptacles. The cost of the occupancy controlled power strips is 

approximately $50–$70 per device. Given the high variation of occupancy depending on 

whether the legislature is in session, these devices could significantly reduce standby plug 

loads. 

Renewable Energy Measures

Install Photovoltaic System on the Southeast Lawn

Photovoltaic Systems4

Photovoltaics are semiconductor devices that convert sunlight directly into electricity. They 

do so without any moving parts and without generating any noise or pollution. They must be 

mounted in an unshaded location; rooftops, carports, and ground-mounted arrays are common 

mounting locations. 

The amount of energy produced by a panel depends on several factors. These factors include 

the type of collector, the tilt and azimuth of the collector, the temperature, and the level of 

sunlight and weather conditions. An inverter is required to convert the direct current (DC) to 

alternating current (AC) of the desired voltage compatible with building and utility power 

systems. The balance of the system consists of conductors/conduit, switches, disconnects, and 

fuses. Grid-connected PV systems feed power into the facility’s electrical system and do not 

include batteries. 

 

4 Lisell, L.; Mosey, G. Feasibility Study of Economics and Performance of Solar Photovoltaics in Nitro, West 

Virginia. NREL/TP-6A2-48594. Golden, CO: NREL (2010). Accessed June 6, 2012: 

http://www.nrel.gov/docs/fy10osti/48594.pdf. 
57 

The PV systems have the following components: 

• PV arrays, which convert light energy to DC electricity 

• Inverters, which convert DC to AC and provide important safety, monitoring, and control 

functions 

• Various wiring, mounting hardware, combiner boxes 

• Monitoring equipment

Figure 28 below shows the major components of a grid-connected PV system and illustrates 

how these components are interconnected.

Figure 28. Major components of grid-connected PV system 

Illustration by Jim Leyshon, NREL 

PV panels are very sensitive to shading. When shade falls on a panel, that portion of the panel 

is no longer able to collect the high-energy beam radiation from the sun. PV panels are made 

up of many individual cells that all produce a small amount of current and voltage. These 

individual cells are connected in series to produce a larger current. If an individual cell is 

shaded, it will act as a resistance to the whole series circuit, impeding current flow and 

dissipating power rather than producing power. 

Ground-Mounted Systems: In many cases, the ground is the best location for a PV system. 

Ground-mounted systems are usually less expensive than roof-mounted systems. Large areas 

with minimal shading obstructions such as trees or other buildings are preferred. A typical 

ground-mounted rack system can achieve power densities on the order of 8 DC watts/ft2, for a 

crystalline silicon panel. 

PV Array: The primary component of a PV system, the PV array, converts sunlight to 

electrical energy; all other components simply condition or control energy use. Most PV 

arrays consist of interconnected PV modules that range in size from 50 to 300 peak DC watts. 

Peak watts are the rated output of PV modules at standard operating conditions of 25°C 

(77°F) and insolation of 1,000 w/m2. Because these standard operating conditions are nearly 

ideal, the actual output will be less under typical environmental conditions. PV modules are 

the most reliable components in any PV system. They have been engineered to withstand 

extreme temperatures, severe winds, and impacts. ASTM E 1038-93 subjects modules to 
58 

impacts from 1-inch hail balls at terminal velocity (55 mph) at various parts of the module. 

PV modules have a life expectancy of 20–30 years, and manufacturers warranty them against 

power degradation for 25 years. The array is usually the most expensive component of a PV 

system; it accounts for approximately two-thirds of the cost of a grid-connected system. There 

is a large choice of PV manufacturers, although it is recommended that the PV be approved 

by Go Solar California.5

 

Inverters: PV arrays provide DC power at a voltage dependent on the configuration of the 

array. This power is converted to AC at the required voltage and number of phases by the 

inverter. Inverters enable the operation of commonly used equipment such as appliances, 

computers, office equipment, and motors. Current inverter technology provides true sine wave 

power at a quality often better than that of the serving utility. A location for the inverter along 

with the balance of the system equipment should be considered. 

Inverters are available that include most or all of the control systems required for operation, 

including some metering and data-logging capability. Inverters must provide several 

operational and safety functions for interconnection with the utility system. The Institute of 

Electrical and Electronic Engineers Inc. (IEEE) maintains standard “P929 Recommended 

Practice for Utility Interface of Photovoltaic (PV) Systems,” which allows manufacturers to 

write “Utility-Interactive” on the listing label if an inverter meets the requirements of 

frequency and voltage limits, power quality, and nonislanding inverter testing. Underwriters 

Laboratory maintains “UL Standard 1741, Standard for Static Inverters and Charge 

Controllers for Use in Photovoltaic Power Systems,” which incorporates the testing required 

by IEEE 929 and includes design (type) testing and production testing. There is a large choice 

of inverter manufacturers, although it is recommended that the inverter be approved by Go 

Solar California.6

Operations and Maintenance (O&M): The PV panels will come with a 25-year performance 

warranty; the inverters come standard with a 5- or 10-year warranty (extended warranties 

available) and would be expected to last 10–15 years. System performance should be verified 

on a vendor-provided website. Wire and rack connections should be checked. For this 

economic analysis, an annual O&M cost of $12.50/kW is based on O&M cost of other fixedaxis, grid-tied PV systems. 

Simulation Methodology

The PV system is assumed to be a standard crystalline silicon panel. Panel and rack 

manufacturers should be consulted to confirm the rated wind load for mounting systems. 

Also, the roof condition should be examined. Figure 29 shows a Google Earth image of the 

available ground area at the most plausible site for a solar system. 

 

5 Go Solar California: http://www.gosolarcalifornia.org/equipment/pvmodule.php 6 Go Solar California: http://www.gosolarcalifornia.org/equipment/inverter.php
59 

Figure 29. Available ground area for a PV system at the Hawaii State Capitol building 

Photo © Google Earth 2012 (edited by Ian Metzger, NREL)

Total available roof area for solar PV observed at the Hawaii State Capitol building was 

22,500 ft2 with an azimuth angle of approximately 30o east of south. No major shading 

obstructions were observed, and greater than 90% solar availability was maintained for the 

available area. 

Results: Table 35 shows the simulation results for the ground-mounted PV system that 

maximizes area for PV. Results show a simple payback period of 6.7 years, which includes 

the federal ITC of 30% and the state of Hawaii tax credit of 35% for a maximum of $500,000. 

The resulting system size is estimated to be 180 kW. PV systems visible from outside of the 

Hawaii State Capitol building could have the added benefits of good public relations and high 

visibility.
60 

Table 35. PV System Specifications and Results

Metric Value

System Size 22,500 ft2

Number of Panels 1,031 (14 ft2 each)

Panel Tilt 20o

Estimated Unit Cost $6.24/w

Capacity 180 kW

Electricity Production 285,434 kWh/yr

Cost Savings $79,922

Implementation Costs $1,150,766

Federal Incentives (30% ITC) $345,230

State Incentive (35% ITC) $281,937

Total Incentives $627,167

Implementation Cost with Incentives $523,598

Simple Payback (without Incentives) 14.5 years

Simple Payback (with Incentives) 6.7 years

CO2 Savings 226 metric tons

Assumptions: 

• Energy savings were calculated using SolOpt simulation software developed at NREL. 

o Weather data for Honolulu, Hawaii, was used for the simulation. 

• A blended electric rate of $0.28 /kWh was assumed. 

• Incentives included the federal ITC of 30%.

• Incentives included the State of Hawaii tax credit of 35% for a maximum of $500,000. 

• System costs were estimated based on costs curves developed by NREL.

• A 30% contingency was added to the implementation cost. 

Incentives, Net Metering, and Financing

The Database of State Incentives for Renewables and Efficiency (DSIRE)7 provides a 

summary of interconnection, net metering, and other incentives. Identifying and leveraging 

federal, state, and local utility incentives and grants are important factors in making PV 

systems cost effective. A private, tax-paying entity that owns PV a system can qualify for a 

30% federal business energy ITC and accelerated depreciation on the PV system, which are 

 

7 http://www.dsireusa.org
61 

worth about 15%. The total potential tax benefits to the tax-paying entity are about 45% of the 

system cost. 

When a utility customer has the ability to generate electricity, the practice of net metering 

allows power to flow both to the utility and from the utility depending on the level of the 

customer’s electricity generation and use. When the customer’s electricity generation is 

greater than electricity use, the extra electricity will flow back onto the utility grid for use by 

other customers. When the customer is generating less electricity than the customer is using, 

the electricity from the grid will flow to the customer to account for the difference. The 

practice is particularly well-suited to small renewable energy systems due to their inherent 

variability in power output and inability to consistently match a customer’s instantaneous 

energy use. There are various ways that net metering can be implemented, but in most cases 

the customer is compensated for the power provided to the grid, essentially offsetting the 

power that the customer must draw from the grid when necessary.8, 9 

Federal and state agencies can still take advantage of these incentives through different 

financing and ownership agreements. Power purchase agreements (PPAs) structure 

agreements so that commercial tax-paying entities own and operate the system and agree to 

sell the power to federal or state agencies at a predetermined price. By doing so, the 

commercial entity can capture the tax credits and pass the savings on to federal and state 

agencies through discounted electricity rates.

Additional Renewable Energy Measures

Consider Solar Water Heating System 

Solar hot water (SHW) systems provide the most favorable payback in buildings with 

relatively high hot water use. Office buildings typically have relatively low hot water use, as 

water is primarily used for hand washing. A SHW system can be installed on the flat portion 

of the roof to meet up to roughly 80% of the hot water demand. There are three types of solar 

water heating collectors: unglazed plastic collectors for low temperatures such as swimming 

pool heating; glazed, insulated flat-plate collectors for mid-temperature service hot water; and 

evacuated tube collectors with reflectors for high-temperature applications. The suggested 

system would use either flat-plate or evacuated tube collectors. Site staff indicated concern 

that an SHW system would change the appearance of the historic building. Therefore, a more 

detailed study is required to determine feasibility.

 

8 Elements of a Sustainable Solar City (2008). July 28, 2009. Accessed August 2012. 

http://www.solaramericacities.energy.gov/PDFs/Elements_of_a_Sustainable_Solar_City.pdf

9 Freeing the Grid (2008). July 29, 2009. Accessed August 2012

http://www.newenergychoices.org/uploads/FreeingTheGrid2008_report.pdf