DOE/EE-0293

Internet: www.eere.energy.gov/femp/

No portion of this publication may be altered in any form without

prior written consent from the U.S. Department of Energy, Energy

Efficiency and Renewable Energy, and the authoring national laboratory.

Leading by example, Demand-Controlled Ventilation 

saving energy and 

taxpayer dollars Using CO2 Sensors 

in federal facilities Preventing energy losses from over-ventilation while maintaining indoor air quality 

Executive Summary 

Demand-controlled ventilation (DCV) using carbon dioxide (CO2) sensing is a combination of two 

technologies: CO2 sensors that monitor CO2 levels in the air inside a building, and an air-handling 

system that uses data from the sensors to regulate the amount of ventilation air admitted. CO2 sensors continually monitor the air in a conditioned space. Given a predictable activity level, such as 

might occur in an office, people will exhale CO2 at a predictable level. Thus CO2 production in the 

space will very closely track occupancy. Outside CO2 levels are typically at low concentrations of 

around 400 to 450 ppm. Given these two characteristics of CO2, an indoor CO2 measurement can be 

used to measure and control the amount of outside air at a low CO2 concentration that is being introduced to dilute the CO2 generated by building occupants. The result is that ventilation rates can be 

measured and controlled to a specific cfm/person based on actual occupancy. This is in contrast to the 

traditional method of ventilating at a fixed rate regardless of occupancy. 

Building codes require that a minimum amount of fresh air be provided to ensure adequate 

air quality. To comply, ventilation systems often operate at a fixed rate based on an assumed 

occupancy (e.g., 15 cfm per person multiplied by the maximum design occupancy). The result 

is there often is much more fresh air coming into buildings than is necessary. That air must be 

conditioned, resulting in higher energy consumption and costs than is necessary with appropriate ventilation. In humid climates, excess ventilation also can result in uncomfortable humidity and mold and mildew growth, making the indoor air quality (IAQ) worse rather than better. 

A lack of adequate fresh air, on the other hand, can make building occupants drowsy and 

uncomfortable. To avoid the problems of too much or too little fresh air, the heating, ventilation, and air-conditioning (HVAC) system can use DCV to tailor the amount of ventilation 

air to the occupancy level. CO2 sensors have emerged as the primary technology for monitoring occupancy and implementing DCV. Energy savings come from controlling ventilation 

based on actual occupancy versus whatever the original design assumed. 

Handheld CO sensor with 2

data logging. Application Domain 

CO2 sensors have been available for about 12 years. An estimated 60,000 CO2 sensors are sold annually for ventilation control in buildings, and the market is growing. There is a potential for millions 

of sensors to be used, since any building that has fresh air ventilation requirements might potentially 

benefit from the technology. 

CO2-based DCV has the most energy savings potential in buildings where occupancy fluctuates during 

a 24-hour period, is unpredictable, and peaks at a high level—for example, office buildings, government facilities, retail stores and shopping malls, movie theaters, auditoriums, schools, entertainment 

clubs and nightclubs. 

CO2 sensors are considered a mature technology and are offered by all major HVAC equipment and controls companies. The technology is recognized in ASHRAE Standard 62, the International Mechanical 
Code (which establishes minimum regulations for mechanical systems), and 

some state and local building codes. 

Although the first CO2 sensors sold were 

expensive, unreliable, and difficult to 

keep calibrated, manufacturers say they 

have largely resolved those problems. 

The unit cost of sensors has dropped 

from $400 to $500 a few years ago to 

$200 to $250 (not including installation). As market penetration increases, 

prices are expected to fall further. 

Several manufacturers produce CO2 sensors for DCV. Most manufacturers of 

thermostats and economizers are integrating CO2 sensors into their products, 

and major manufacturers of packaged 

rooftop HVAC systems offer factoryinstalled CO2 sensors as an option. 

Benefits 

DCV saves energy by avoiding the heating, cooling, and dehumidification of 

more ventilation air than is needed. CO2 

sensors are the most widely accepted 

technology currently available for implementing DCV. Additional benefits of 

CO2-based DCV include 

• Improved IAQ—By increasing ventilation if CO2 levels rise to an unacceptable level, 

• Improved humidity control—In 

humid climates, DCV can prevent 

unnecessary influxes of humid 

outdoor air that makes occupants 

uncomfortable and encourages 

mold and mildew growth. 

Estimated Savings 

The potential of CO2-based DCV 

for operational energy savings has 

been estimated in the literature at 

from $0.05 to more than $1 per square 

foot annually. The highest payback 

can be expected in high-density spaces 

in which occupancy is variable and 

unpredictable (e.g., auditoriums, some 

school buildings, meeting areas, and 

retail establishments), in locations with 

high heating and/or cooling demand, 

and in areas with high utility rates. 

Design Considerations 

CO2 sensing is a fairly simple technology, and installation of the sensors themselves is not complicated. Including 

CO2-based DCV in a new HVAC 

installation should not add significantly 

to the difficulty of commissioning the 

system. However, retrofitting an existing 

system for DCV may be more problematic, particularly for an older system with 

pneumatic controls. Applying a CO2­

based DCV strategy using ASHRAE 62 

is more complicated than simply installing CO2 sensors and using them to control dampers. In variable-air-volume 

systems, particularly, fairly complex 

calculations and control algorithms 

may be necessary to program the control system properly for DCV. The use 

of a more complex control algorithm 

often provides increased savings and 

improved IAQ; while it increases the 

level of commissioning, the results outweigh the extra initial time and expense. 

Maintenance Impact 

Maintenance of the sensors themselves 

is not generally reported to be a problem. Manufacturers offer sensors that 

recalibrate themselves automatically 

and that are guaranteed not to need 

Disclaimer 

calibration for up to 5 years. However, 

it is recommended that calibration 

be checked periodically by comparing 

sensor readings during a several-hour 

period when the building is unoccupied with readings from the outdoor air. Many sensor models are 

able to sense calibration problems 

and alert maintenance personnel if 

they are malfunctioning. 

Costs 

Costs for sensors have dropped by 

about 50% over the last several years. 

Sensors typically cost about $250 to 

$260 each, uninstalled. For a new 

system, the installed cost will generally be about $600 to $700 per zone. 

For a retrofit system, the cost will 

depend on what type of control system the building has. A controls contractor estimates installed costs for 

retrofit applications at from $700 to 

$900 per zone for systems with an 

existing DDC programmable controller and from $900 to $1200 per zone 

for systems with pneumatic, electronic, or application-specific DDCs. 

Installation costs for wireless systems 

are minimal beyond the cost of the 

actual sensor and gateway that can 

serve multiple sensor units. 

In addition to the installation of the 

sensors, other components such as 

variable frequency drives and control 

input and output hardware often are 

needed to control the whole building, 

incrementally increasing the overall 

installed project cost beyond just the 

sensor installation cost. 

This report was sponsored by the United States Department of Energy, Energy Efficiency and Renewable Energy, 

Federal Energy Management Program. Neither the United States Government nor any agency or contractor thereof, 

nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for 

the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents 

that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or 

service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency or contractor thereof. The views 

and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or 

any agency or contractor thereof. 
Contents


Abstract ............................................................................................................................................. 3


About the Technology ....................................................................................................................... 3


Application Domain 

Energy-Saving Mechanism 

Other Benefits 

Variations 

Installation 

Federal-Sector Potential ..................................................................................................................... 7 

Estimated Savings 

and Market Potential 

Laboratory Perspective 

Application ....................................................................................................................................... 8 

Application Screening 

Where to Apply 

What to Avoid 

Design Considerations 

Maintenance Impact 

Equipment Warranties 

Codes and Standards 

Costs 

Utility Incentives and Support 

Technology Performance ................................................................................................................. 12 

Field Experience 

Energy Savings 

Maintenance Impact 

Case Study ...................................................................................................................................... 13 

Facility Description 

Existing Technology Description 

New Technology Equipment Selection 

Building Upgrade Assessment 

Life-Cycle Cost 

Post-Implementation Experience 

The Technology in Perspective ........................................................................................................ 19 

The Technology’s Development 

Technology Outlook 

Manufacturers ................................................................................................................................. 20 

Who is Using the Technology .......................................................................................................... 20 

For Further Information .................................................................................................................. 21 

Appendix A Federal Life-Cycle Costing Procedures 

and the BLCC Software.............................................................................................. 23


FEDERAL ENERGY MANAGEMENT PROGRAM — 1 
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2 — FEDERAL ENERGY MANAGEMENT PROGRAM 
Abstract 

Demand-controlled ventilation (DCV) 

using carbon dioxide (CO2) sensors 

combines two technologies: advanced 

gas sensing and an air-handling system 

that uses data from the sensors to regulate ventilation. CO2 sensors continually monitor the air in a conditioned 

space. Since people exhale CO2, the 

difference between the indoor CO2 concentration and the level outside the 

building indicates the occupancy and/ 

or activity level in a space and thus its 

ventilation requirements. The sensors 

send CO2 readings to the ventilation 

controls, which automatically increase 

ventilation when CO2 concentrations 

in a zone rise above a specified level. 

Either too little or too much fresh air 

in a building can be a problem. Overventilation results in higher energy 

usage and costs than are necessary with 

appropriate ventilation while potentially 

increasing IAQ problems in warm, 

humid climates. Inadequate ventilation leads to poor air quality that can 

cause occupant discomfort and health 

problems. To ensure adequate air quality in buildings, the American Society 

of Heating, Refrigerating and AirConditioning Engineers (ASHRAE) 

recommended a ventilation rate of 

15–20 cfm per person in ASHRAE 

Standard 62-1999. To meet the standard, many ventilation systems are 

designed to admit air at the maximum 

level whenever a building is occupied, 

as if every area were always at full occupancy. The result, in many cases, has 

been buildings that are highly overventilated. The development of CO2­

based DVC was driven in part by 

the need to satisfy ASHRAE 62 without overventilating. 

Non-dispersive infrared CO2 sensors are 

the type most widely used. All major 

makers of heating, ventilation, and airconditioning (HVAC) equipment and 

HVAC controls offer the sensors, either 

as separate units or as a part of packaged 

HVAC systems. Although earlier sensors 

were plagued by reliability and calibration problems, those issues seem to have 

been largely resolved in newer models. 

Typically, a CO2 sensor is installed on 

the wall like a thermostat. Newer products entering the market combine thermostats and CO2 and relative humidity 

sensors, the three primary indicators 

of human comfort, in one unit. Sensors 

may be installed inside ductwork rather 

than wall-mounted, but in-duct installation is not recommended for all applications. In a conventional “wired” CO2 

sensor system, wires are run from the 

sensors to the HVAC controls or to 

the damper actuators. With wireless 

CO2 sensors, the data are transmitted 

to the building automation system via 

a wireless gateway for use in the control algorithm. Properly functioning 

modulating dampers are necessary. 

Pneumatic controls may need to be 

replaced with electronic or direct digital controls. In a retrofit installation, 

dampers may need to be repaired or 

upgraded to work with the sensors. 

In all applications of CO2-based DCV, 

a minimum base ventilation rate must 

be provided at all times the building is 

occupied. A higher rate may be needed 

for buildings in which building materials, contents, or processes release 

chemicals into the air. DCV should be 

used only in areas where human activity is the main reason for ventilating the 

space. Industrial or laboratory spaces 

are unsuitable for CO2-based ventilation control. 

The potential of CO2-based DCV for 

energy savings is estimated at from 

$0.05 to more than $1 per square foot 

annually. The highest payback can be 

expected in high-density spaces in which 

occupancy is variable and unpredictable 

(e.g., auditoriums, some school buildings, meeting areas, and retail establishments), in locations with high 

heating and/or cooling demand, and 

in areas with high utility rates. Case 

studies show DCV offers greater savings 

for heating than for cooling. In areas 

where peak power demand and peak 

prices are an issue, DCV can be used 

to control loads in response to realtime prices. In those locations, DCV 

may enable significant cost savings 

even with little or no energy savings. 

CO2-based DCV does not interfere with 

economizers or other systems that introduce outdoor air into a building for 

cooling. Economizer operation overrides DCV when conditions warrant 

economizer use. Buildings that use 

evaporative cooling may not benefit 

from DCV during the cooling season. 

Costs for sensors have dropped by about 

50% over the last several years as the 

technology has matured and become 

more widely used. Sensors typically cost 

about $250 to $260 each, uninstalled. 

For a new system, the installed cost 

will generally be about $600 to $700 

per zone. For a retrofit system, the cost 

will depend on what type of control 

system the building has and the degree 

of difficulty of installing signal and 

power wiring for a wired system. A 

complete wireless sensor system can 

be deployed quickly and without additional cost as such systems are battery 

powered. Given the advances in battery technology and microprocessorcontrolled power management, sensors 

can be expected to operate for 2–3 years 

before they require a battery change. 

About the Technology 

Demand-controlled ventilation (DCV) 

using carbon dioxide (CO2) sensing is 

a combination of two technologies: 

CO2 sensors that monitor the levels of 

CO2 in the air inside a building, and 

an air-handling system that uses data 

from the sensors to regulate the amount 

of outside air admitted for ventilation. 

DCV operates on the premise that 

basing the amount of ventilation air 

on the fluctuating needs of building 

occupants, rather than on a pre-set, 

fixed formula, will save energy and at 

the same time help maintain indoor air 

quality (IAQ) at healthy levels. 

CO2 sensors continually monitor the 

air in a conditioned space. Because 

people constantly exhale CO2, the difference between the indoor CO2 concentration and the level outside the 

building indicates the occupancy and/ 

or activity level in a space and thus its 

ventilation requirements. (An indoor/ 

FEDERAL ENERGY MANAGEMENT PROGRAM — 3 
Figure 1. The relationship between CO2 and ventilation 

rates, assuming office-type activity. 

consumption and costs than 

would be necessary with 

appropriate ventilation. In 

addition, in humid climates, 

an overload of fresh air can 

result in uncomfortable 

humidity and mold and 

mildew growth, making 

the indoor air quality 

worse rather than better. 

A lack of adequate fresh 

air, on the other hand, can 

make building occupants 

drowsy and uncomfortable 

as occupancy-related contaminants accumulate. 

A CO2 level of around 

1100 ppm (a differential 

of 700 ppm, assuming the 

outdoor CO2 differential of 700 ppm 

is usually assumed to indicate a ventilation rate of 15 cfm/person; a differential of 500 ppm, a 20 cfm/person 

ventilation rate, etc.) The sensors send 

CO2 readings to the air handling system, which automatically increases 

ventilation when CO2 concentrations 

in a zone rise above a specified level. 

Building codes specify that a minimum 

amount of fresh air be brought into a 

building to provide for adequate air 

quality. The American Society of Heating, Refrigerating and Air-Conditioning 

Engineers (ASHRAE) recommends a 

ventilation rate of 15-20 cfm per person 

in ASHRAE Standard 62.1 To comply 

with codes, building ventilation systems 

often operate at constant or predetermined rates regardless of the occupancy 

level of the building. Many systems ventilate buildings at the maximum level 

all the time, as if every area were always 

fully occupied. Others are programmed 

to accommodate expected occupancy, 

varying the ventilation rate by time of 

day but without regard to the actual 

occupancy level. The result often is 

more ventilation air coming into buildings than is necessary. That air must 

be heated, cooled, or dehumidified/ 

humidified, resulting in higher energy 

outdoor air CO2 level is 

around 400 ppm) indicates that the 

ventilation rate has dropped below 

acceptable levels and that contaminants in the air are increasing. 

To avoid the problems of too much or 

too little fresh air, a heating, ventilation, and air-conditioning (HVAC) 

system can employ DCV to adjust the 

amount of ventilation air supplied to 

an indoor space according to the occupancy level. CO2 sensors have emerged 

as the primary technology for monitoring occupancy and implementing DCV. 

Application Domain 

CO2 sensors have been available for 

about 12 years. An estimated 60,000 

CO2 sensors are sold annually for ventilation control in buildings, and a manufacturer estimates the market is growing 

at about 40 to 60% per year. There is 

a potential for millions of sensors to be 

used, since any building that has fresh 

air ventilation requirements could 

potentially benefit from this refined 

control technology. 

DCV using CO2 sensors has the most 

energy-saving potential in buildings 

where occupancy fluctuates during a 

24-hour period, is unpredictable, and 

peaks at a high level, for example, office 

buildings, government facilities, retail 

stores and shopping malls, movie theatres, auditoriums, schools, entertainment clubs and nightclubs. In buildings 

with more stable occupancy levels, DCV 

can ensure that the target ventilation 

rate per person is being provided at all 

times. DCV is more likely to reduce 

energy costs in areas with high utility 

rates or climate extremes. 

CO2-based DCV can operate in conjunction with economizers or other 

systems that introduce outdoor air 

into a building for heating or cooling. 

However, energy savings may be less 

where economizers are in use, depending on climate, occupancy schedule, 

and building type. 

Buildings that use evaporative cooling 

may not benefit from DCV during the 

cooling season, and those that use heat 

exchangers to transfer heat between 

incoming and outgoing air may not 

realize significant energy savings. 

In the next revision of its building code, 

California will begin requiring CO2­

based DCV in all buildings housing 

25 people or more per 1000 ft2

. A proposed change in the Oregon building 

code would require DCV for HVAC 

systems with ventilation air requirements of at least 1500 cfm, serving 

areas with an occupant factor of 20 or 

less. ASHRAE 90 requires CO2 sensors 

for DCV in high-density applications. 

The U.S. Green Building Code gives 

points in its Leadership in Energy and 

Environmental Design (LEED) rating 

system for use of CO2-based ventilation 

control in buildings. 

CO2 sensors are considered a mature 

technology and are offered by all major 

HVAC equipment and controls companies. The technology is recognized in 

ASHRAE Standard 62, the International 

Mechanical Code (which establishes 

minimum regulations for mechanical 

systems), and some state and local 

building codes. The first CO2 sensors 

sold were expensive, unreliable, and 

1 An ASHRAE standard is usually designated by a standard number and the year in which it was last revised. Standard 62 is under continuous maintenance and is constantly being revised. 

4 — FEDERAL ENERGY MANAGEMENT PROGRAM 
difficult to keep calibrated accurately. 

However, manufacturers say they have 

largely resolved those problems-the 

units currently available generally are 

self-calibrating and similar to thermostats in price and reliability. A few years 

ago, sensors cost around $400 to $500 

each; the cost now is usually about 

$200 to $250 per sensor (not including 

installation). As market penetration 

increases, sensor prices are expected 

to fall further. 

Several manufacturers produce CO2 sensors for use in DCV. Most manufacturers 

of thermostats and economizers are integrating CO2 sensors into their products, 

and major manufacturers of packaged 

rooftop HVAC systems offer factoryinstalled CO2 sensors as an option. 

CO2-based DCV is suitable only when 

there is a means of automatically adjusting the ventilation air supply (e.g., 

variable-speed fans or some variable 

damper arrangement). If this control is 

not presently available, the savings from 

DCV may justify the modifications to 

accommodate this degree of control. 

CO2 sensors designed for DCV are 

suitable only for controlling occupantrelated ventilation. DCV does not 

eliminate the need for a base rate of 

ventilation to prevent degradation of 

air quality from contaminant sources 

unrelated to building occupancy, such 

as emissions from building materials. 

Thus CO2-based DCV may not be 

appropriate—or may require higher target ventilation settings-in new buildings 

or others where there are contaminants 

not related to human occupancy, as it 

may not provide sufficient fresh air to 

dilute those contaminants. The CO2 

sensors used for DCV are not appropriate to monitor CO2 for medical or 

industrial purposes that demand precise air quality control. 

DCV should be used only in areas where 

human activity is the main reason for 

ventilating the space. Industrial or 

laboratory spaces that are subject to 

indoor air quality (IAQ) degradation 

from a wide variety of sources are unsuitable for CO2-based ventilation control. 

Energy-Saving Mechanism 

The energy savings from CO2 sensors 

for DCV result from the avoidance of 

heating, cooling, and dehumidifying 

fresh air in excess of what is needed 

to provide recommended ventilation 

rates. Many HVAC systems ventilate 

at a constant fixed level, usually the 

level prescribed for full occupancy, and 

thus provide more fresh air per occupant than the designed ventilation rate 

much of the time. Moreover, systems 

using fixed ventilation rates cannot 

accurately account for unanticipated 

air infiltration into a building (e.g., from 

leakage or opened windows) and adjust 

the fresh air intake accordingly. 

DCV based on CO2 sensing allows realtime control of the ventilation levels 

according to building occupancy. If a 

building is only 50% full, then only 

50% of the design-rate ventilation air, 

not 100%, is pulled in. CO2 sensors are 

the most widely accepted technology 

currently available for implementing 

DCV. They do this by increasing the 

ventilation rate whenever the CO2 level 

in a space reaches a predetermined level 

that represents a differential between 

the indoor and outdoor CO2 levels. The 

outdoor CO2 level is slightly dependent 

on local conditions and elevation, but 

can generally be assumed to be around 

400 ppm. An indoor level of 1100 ppm 

of CO2 thus represents a 700-ppm differential and indicates a ventilation rate 

of 15 cfm per person in the occupied 

space. A differential of 500 ppm in the 

same space would indicate a ventilation 

rate of 20 cfm per person. 

The technology most often used in CO2 

sensors is non-dispersive infrared spectroscopy. It is based on the principle 

that every gas absorbs light at specific 

wavelengths. Carbon dioxide sensors 

calculate CO2 concentrations by 

measuring the absorption of infrared 

light (at a wavelength of 4.26 microns) 

by CO2 molecules. The sensor apparatus incorporates a source of infrared 

radiation, a detector, and electronics to 

detect the absorption. Air from the area 

being monitored diffuses into a chamber 

Figure 2. Typical non-dispersive infrared 

spectroscopic CO2 sensor. 

that has a light source at one end and a 

light detector at the other. Selective 

optical fibers mounted over the light 

detector permit only light at the 4.26­

micron wavelength absorbed by CO2 

to pass through to the detector. As 

CO2 levels rise, more infrared light is 

absorbed and less light is detectable. 

Photo-acoustic CO2 sensors also are 

available. In these sensors, also, air 

diffuses into a chamber in the sensors 

and is exposed to light at the wavelength absorbed by CO2. As the CO2 

molecules absorb light energy, they 

heat the air chamber and causes pressure pulses. A piezo-resistor senses the 

pulses and transmits data to a processor that calculates the CO2 level. 

Electrochemical sensors measure the 

current transmitted across a gap filled 

with an electrochemical solution. CO2 

decreases the pH of the solution, freeing conductive metal ions. A weak 

electrical current can then flow across 

the gap; the current signals an increase 

in the CO2 level. 

Mixed-gas sensors also can detect CO2 

along with other gases in the air, but 

they have not proved to be effective 

for DCV because they do not measure 

CO2 specifically and cannot be tied to 

FEDERAL ENERGY MANAGEMENT PROGRAM — 5 
ventilation rates as explicitly as a CO2 

sensor can. 

Sensors generally are either wallmounted in the space to be monitored 

or mounted inside the duct system. 

(Wall-mounted sensors usually are recommended because duct-mounted units 

provide data on the average CO2 concentration in multiple spaces rather than 

on the CO2 levels in individual areas.) 

The sensors monitor CO2 concentrations continually and send data to the 

system for controlling the ventilation 

equipment. Various types of control systems can be used to incorporate CO2 

sensing: simple setpoint control that 

activates a fan or damper when CO2 

levels exceed a setpoint; proportional 

control, in which sensor data adjust 

ventilation air volume through a range 

of levels; proportional-integral control, 

in which fresh air intake is controlled 

not only by the CO2 level but also by 

the rate at which the level is changing; 

and two-stage controls for zone-based 

systems in which both temperature sensors and CO2 sensors control ventilation. 

Other Benefits 

Potential secondary benefits of CO2­

based DCV include: 

• Improved IAQ: By increasing the 

supply of fresh air to the building 

if CO2 levels rise to an unacceptable 

level, the technology could prevent 

under-ventilation that results in 

poor air quality and stuffy rooms. 

• Improved humidity control: In humid 

climates, DCV can prevent unnecessary influxes of humid outdoor air 

that causes occupants to be uncomfortable and encourages the growth 

of mold and mildew. 

• Records of air quality data: Sensor 

readings can be logged to provide a 

reliable record of proper ventilation 

in a building. Such records can be 

useful in protecting building owners 

against ventilation-related illness or 

damage claims. 

• Reduced operational running times 

for the major HVAC equipment: 

Improving the ability to condition 

the building could delay start-times 

of the HVAC equipment during 

morning pre-conditioning periods 

by as much as several hours on a 

Monday morning in humid climates, 

resulting in incremental energy and 

cost savings. 

Variations 

DCV can be implemented using methods other than CO2 sensing to indicate 

occupancy levels or air quality conditions. For example, humidity sensors, 

motion detectors, particle counters, 

volatile organic contaminant sensors, 

and mixed-gas sensors can be used to 

regulate DCV. Time-controlled ventilation (e.g., using programmed time 

clocks) is also an option for buildings 

that are occupied only during certain 

times, for example, office buildings 

and schools. Based on a review of the 

literature, it appears that CO2 sensors 

are becoming the industry standard for 

typical DCV applications. 

CO2 sensors are of three main types: 

infrared, electrochemical, and photoacoustic. Based on the literature, infrared sensors appear to be the type most 

commonly used for DCV applications. 

Combination sensing units are available that package wall-mounted CO2 

sensors with thermostats or with 

humidity sensors. 

There are numerous variations in the 

types of HVAC systems and control 

systems with which CO2-based DCV 

is implemented. CO2-based DCV 

capability can be added to an existing 

system by installing sensors and connecting them with the air handling 

systems. Increasingly, new HVAC systems are being factory-equipped with 

input and controls strategies to accept 

CO2-based DCV. 

Installation 

Typically, a CO2 sensor is installed 

on the wall like a thermostat. Newer 

products entering the market combine thermostats and CO2 and relative 

humidity sensors, the three primary 

indicators of human comfort, in one 

unit. Sensors may be installed inside 

ductwork instead of on a wall, but 

in-duct installation is not recommended 

for applications where the sensor would 

All of these types of systems can be modified to accomplish a DCV strategy 

Control Type Minimum Modification Recommended Modification 

All Apply ASHRAE Standard 62-1999 with CO2 

sensors provided in zones with high critical 

outside air (OA) calculations 

Provide CO2 sensors in all zones, using the 

highest zone to increase the fresh air provided 

by the associated air-handling unit (AHU) 

Pneumatic Provide electronic-to-pneumatic transducer 

to limit the OA damper position 

Upgrade the AHU to DDC 

programmable control 

Electronic Provide electronic device to limit the OA 

damper position 

Upgrade the AHU to DDC 

programmable control 

DDC–application specific Provide electronic device to limit the OA 

damper position 

Upgrade the AHU to DDC 

programmable control 

DDC-programmable Modify the control program to provide 

new DCV strategy 

Same as minimum 

6 — FEDERAL ENERGY MANAGEMENT PROGRAM 
Figure 3. CO2 equilibrium levels at various ventilation rates. 

average readings from several different 

areas. With hardwired sensors (those 

requiring both power and signal wiring), 

wires are run from the sensors to the 

building’s HVAC control system or to 

the actuator that controls the fresh air 

supply. Wireless sensors require neither 

power nor signal wiring, and the sensor 

data are fed into the HVAC controls 

via a gateway using one of several communication protocols. 

In a building retrofit, dampers may need 

to be repaired or upgraded to work with 

the sensors. Properly functioning modulating dampers are necessary. Pneumatic 

controls will need to be replaced with 

electronic or direct digital controls 

(DDCs); it may also be worthwhile 

to replace existing electronic controls 

with DDCs. Actuator modules that 

do not have input points for the sensors will need to be upgraded. 

Part of the preparation for implementing DCV is to monitor the air in the 

outdoor areas surrounding the building for at least a week to establish the 

CO2 concentration in the ventilation 

air. The differential between the CO2 

levels of the outdoor and indoor air 

will determine the amount of fresh 

air needed to meet ventilation requirements. CO2 concentrations in all zones 

inside the conditioned space also should 

be monitored for several days to indicate existing ventilation levels in the 

zones. This monitoring may identify 

problems with air-handling systems 

that need to be corrected before DCV 

is implemented. 

To ensure that the sensors are correctly 

calibrated and working properly, a 

hand-held monitor should be used to 

check CO2 concentrations inside the 

buildings regularly for a few days after 

the system begins operating. The readings from the monitor should be compared with the readings the sensors are 

sending to the ventilation system controls. Sensors that prove to be improperly calibrated should be recalibrated. 

In all applications of CO2-based DCV, 

a minimum ventilation rate should be 

provided at all times the building is 

occupied. A rate of 20–30% of the original design ventilation rate for the space 

at maximum occupancy is often recommended as a new baseline ventilation 

rate. A higher rate may be needed for 

buildings in which building materials, 

contents, or processes release chemicals 

into the air. 

Federal-Sector Potential 

Federal Technology Alerts target technologies that appear to have significant 

untapped federal-sector potential and 

for which some installation experience 

exists. CO2 sensors are recognized as 

having potential to reduce energy 

consumption and costs resulting from 

over-ventilation of buildings while 

guarding against under-ventilation. 

Estimated Savings 

and Market Potential 

CO2-sensors for demand-controlled 

ventilation are recognized as having 

potential to reduce energy consumption, costs, and emissions. 

Demand-controlled ventilation has not 

been assessed by the New Technology 

Demonstration activities. There are no 

known estimates of the savings potential of CO2-based DCV for the federal 

building sector. Therefore, this report 

cannot adequately quantify the energysavings potential of the application of 

this technology for the federal sector. 

The literature about DCV includes 

numerous estimates and models of the 

savings potential of DCV, as well as 

accounts of monitored savings in specific applications. The predicted and 

actual savings vary widely depending 

on climate, type of HVAC system with 

which DCV is implemented, occupancy 

patterns in the space in which is it implemented, and other operating conditions. 

The capability of the building staff to 

keep equipment adequately maintained 

and operating properly also may affect 

savings significantly. 

The potential of CO2-based DCV for 

operational energy savings has been 

estimated in some of the literature at 

from $0.05 to more than $1 per square 

foot annually. The highest payback can 

be expected in high-density spaces in 

which occupancy is variable and unpredictable (e.g., auditoriums, some school 

buildings, meeting areas, and retail 

establishments), in locations with high 

heating and/or cooling demand, and in 

areas with high utility rates. 

A report by Lawrence Berkeley National 

Laboratory cited five case studies in large 

office buildings with CO2-based DCV, 

all of which reported energy savings 

FEDERAL ENERGY MANAGEMENT PROGRAM — 7 
that resulted in payback times of from 

0.4 to 2.2 years. Two of the studies were 

computer simulations. One of those, 

conducted in 1994, simulated a 10-floor 

office building located in Miami, 

Atlanta, Washington, D.C., New York, 

and Chicago. The simulation predicted 

large gas savings for heating and smaller 

electricity savings, resulting in predicted 

payback times for the different locations of from 1.4 to 2.2 years. 

A 1999 study modeled the impact 

of DCV and economizer operation 

on energy use in four building types 

(office, retail, restaurant, school) in 

three locations representing different 

climates: Atlanta; Madison, Wisconsin; 

and Albuquerque. For cooling, predicted 

savings attributed to DCV depended 

greatly on location-savings were larger 

in Atlanta and Madison because humidity made economizer operation less 

beneficial. In low-humidity Albuquerque, economizer operation was much 

more significant than DCV in reducing cooling energy demand. In all three 

locations, DCV resulted in large savings 

in heating energy—27%, 38%, and 

42% for the office building in Madison, 

Albuquerque, and Atlanta, respectively; 

from 70% in Madison to over 80% in 

Atlanta and Albuquerque for the school; 

and over 90% in all three locations for 

the retail and restaurant spaces. Similar 

results were obtained for 17 other U.S. 

locations modeled. In all locations, the 

office building showed the most modest savings. 

A recent proposal for a change to the 

Oregon building code to require DCV 

in some applications cites a DOE2 

analysis of implementing a DCV strategy in a middle school gymnasium. 

It predicts energy cost savings of 

$3700 per year from DCV and a 

simple payback of about 6 months. 

No estimate of market potential for 

CO2-based DCV in the federal sector 

was available. 

Laboratory Perspective 

Research on CO2-based DCV at the 

national laboratories has been limited 

so far. The technology is generally 

regarded as a valid operational strategy 

that offers potential for energy and 

cost savings and protection of IAQ in 

many facilities. A study conducted by 

Lawrence Berkeley National Laboratory 

concludes that sensor-regulated DCV 

is generally cost-effective in buildings 

in which the measured parameter (e.g., 

CO2) is the dominant emission, the 

occupancy schedule and levels are varied and unpredictable, and the heating/ 

cooling requirements are large. Monitoring of CO2-based DCV systems is 

under way at some national laboratories 

to quantify savings and analyze effects 

on IAQ. 

Some caveats have emerged from laboratory experience. Calibration drift has 

been observed to be a problem in some 

sensors. The management of energy 

management systems so that they 

admit ventilation air at an appropriate CO2 level is another. A researcher 

at Oak Ridge National Laboratory 

who works with building projects at 

federal facilities noted that a skilled, 

well-trained building maintenance 

staff is essential to proper functioning 

of the sensors and associated control 

systems. If other HVAC control systems in a building frequently function 

improperly, there probably will be 

problems with CO2 sensors and DCV 

controls, also. He advises that a test 

installation be tried first to ensure that 

the building staff understand how the 

devices work, that the devices function 

properly, and that the staff can handle 

a larger DCV implementation. 

Application 

This section addresses technical aspects 

of applying the technology. The range 

of applications and climates in which 

the technology can be best applied are 

addressed. The advantages, limitations, 

and benefits in each application are 

enumerated. Design and integration 

concerns for the technology are discussed, including equipment and 

installation costs, installation details, 

maintenance impacts, and relevant 

codes and standards. Utility incentives 

and support are also discussed. 

Application Screening 

DCV based on CO2 sensing offers the 

most potential energy savings in buildings where occupancy fluctuates during a 24-hour period, is somewhat 

unpredictable, and peaks at a high 

level. It is also more likely to reduce 

energy costs in locales that require 

heating and cooling for most of the 

year and where utility rates are high. 

Savings opportunities are the greatest in 

buildings with low average occupancy 

levels compared with the design occupancy levels. Larger savings are likely 

in buildings that supply 100% outside 

air to conditioned spaces than in buildings that supply a mixture of outside 

and recirculated air. 

Types of buildings in which CO2-based 

DCV is likely to be cost-effective include 

large office buildings; assembly rooms, 

auditoriums, and lecture halls; large 

retail buildings and shopping malls; 

movie theaters; restaurants, bars and 

nightclubs; banks; outpatient areas in 

hospital; and hotel atriums or lobbies. 

In primary and secondary schools, where 

occupancy is variable but predictable, 

time-controlled DCV may be more 

Figure 4. Percent of total ventilation capacity percent building occupancy. 

8 — FEDERAL ENERGY MANAGEMENT PROGRAM 
cost-effective. College classroom buildings and large lecture rooms with variable occupancy through the day and the 

week are more appropriate candidates. 

CO2-based DCV does not interfere with 

economizers or other systems that introduce outdoor air into a building for 

cooling. Economizer operation overrides DCV when conditions warrant 

economizer use. The energy and cost 

savings for such arrangements depend 

on climate, occupancy schedule, and 

building type. Warm, humid climates 

(e.g., the Southeast) offer the most 

potential to save cooling energy with 

DCV because high humidity reduces 

opportunities for economizer cooling. 

In dry climates such as the desert Southwest, economizer operation may save 

more cooling energy than DCV. Additional cooling savings from DCV may 

be insignificant in such climates, and 

DCV without economizer cooling 

may even result in an energy penalty. 

Buildings that use evaporative cooling 

may not benefit from DCV during the 

cooling season. 

Case studies generally show greater 

savings for heating than for cooling 

in all climates. Heating savings are 

greatest where heating the ventilation air accounts for a large portion 

of the energy demand. A building 

with exchangers to transfer heat 

between incoming and exhaust air has 

less potential for savings from DCV 

because the heat exchangers reduce 

the energy penalty of ventilation air. 

In areas where peak power demand and 

peak prices are an issue, DCV can be 

used to control loads in response to realtime prices. In those locations, DCV 

may enable significant cost savings 

even with little or no energy savings. 

DCV can be implemented only in buildings in which the outside air supply can 

be automatically adjusted. If the airhandling system lacks that capability, 

it must be upgraded before CO2-based 

DCV can be implemented. It is recommended that pneumatic controls be 

replaced with electronic or digital controls to implement CO2-based DCV. 

The cost of installing CO2 sensors for 

DCV depends on how easily the existing control system can incorporate 

them. If the existing system has digital 

controls and available input points on 

the control modules for wired sensors, 

costs will be lower and implementation easier. Wireless sensors may be 

more easily integrated into an existing 

control system, as no new input control modules are needed. 

Modeling is recommended, if feasible, 

to estimate the energy savings and 

cost-effectiveness of DCV in a specific situation. 

CO2 from human respiration must be 

the dominant pollutant in a space for 

CO2-based DCV to be appropriate. 

Otherwise, it could lead to insufficient 

ventilation. Occupancy-based DCV is 

inappropriate for spaces with high levels of contaminants unrelated to human 

occupancy, including industrial or 

laboratory spaces. If CO2-based DCV 

is used in a new building or other space 

containing materials that release irritating emissions (e.g., a clothing or 

carpet store), the target ventilation 

rate must be high enough to ensure 

that emissions are adequately diluted. 

An HVAC system with CO2-based 

DCV needs to be capable of a daily 

pre-occupancy (e.g., early morning) 

purge of inside air to avoid exposing 

occupants to emissions (e.g., from 

building materials) that accumulate 

while ventilation is at a low level. 

Although DCV was developed mainly 

as an energy-efficiency technology, it 

also is useful to ensure acceptable IAQ. 

In a properly operating system, CO2­

based DCV ensures that the target 

ventilation rate per person is being 

provided at all times. Thus it may be 

appropriate for spaces where there are 

IAQ concerns. It may also help control 

the growth of mold and mildew by 

reducing unnecessarily large influxes 

of humid outdoor air. 

Where to Apply 

• Buildings where occupancy fluctuates during a 24-hour period, is 

somewhat unpredictable, and peaks 

at a high level. 

•	 Locales that require heating and 

cooling for most of the year. 

• Areas where utility rates are high. 

• Areas where peak power demand 

and prices are high. 

• Buildings with low average occupancy compared with the design 

occupancy. 

•	 Large office buildings; assembly 

rooms, auditoriums, and lecture 

halls; large retail buildings and shopping malls; movie theaters; restaurants, bars and nightclubs; banks; 

outpatient areas in hospital; and 

hotel atriums or lobbies. 

• Warm, humid climates. 

• Buildings in which heating/cooling/ 

dehumidifying the ventilation air 

accounts for a large portion of the 

energy demand. 

• Buildings in which the outside air 

supply can be automatically adjusted. 

• Buildings with HVAC systems that 

have, or can be upgraded to, electronic or digital controls. 

• Spaces in which CO2 from human 

respiration is the only or dominant 

pollutant. 

• Spaces that do not have high levels 

of contaminants unrelated to human 

occupancy (e.g., industrial or laboratory spaces). 

• Buildings in which poor IAQ resulting 

from under-ventilation or excessive 

humidity resulting from under- or 

over-ventilation is a concern. 

Precautions 

The following precautions should be 

kept in mind in considering the use 

of CO2-based DCV. 

• Sensors should be placed where 

they will provide readings that are 

close to actual conditions in the 

spaced to be controlled. 

• Wall-mounted sensors are generally 

preferable to duct-mounted sensors. 

FEDERAL ENERGY MANAGEMENT PROGRAM — 9 
• Sensors should not be mounted 

in locations where people will 

regularly breathe directly on them 

(e.g., at standing level near the coffee machine). 

• Don’t buy carelessly—choose sensors 

with a reputation for performing well 

in terms of self-calibration, drift, 

accuracy, and reliability. 

• A competent, well-trained maintenance staff is important to a successful implementation. 

• In a retrofit, it is important to make 

a thorough study of the HVAC system and troubleshoot for existing 

ventilation problems before installing a DCV system. 

• A new base ventilation rate should be 

provided at any time the building is 

occupied. An often-cited guideline is 

20 to 30% of the original design rate. 

• Applications in moderate climates, 

especially where economizer operation 

contributes substantially to cooling, 

may show little energy/cost savings. 

• Spaces where there are high levels of 

contaminants not related to occupancy may demand a higher ventilation rate than would be provided 

by DCV based solely on CO2 levels. 

• During the first year or so in a new 

building, it is advisable to maintain 

a higher ventilation rate than CO2 

sensing would indicate to ensure 

proper dilution of emissions from 

new materials. 

Design Considerations 

CO2 sensing is a fairly simple technology, and installation of the sensors 

themselves is not complicated. Sensor 

voltage, power, and control output 

requirements are similar to those used 

commonly by thermostats. For wired 

sensor installations, the type of wire used 

for the signal wiring is often critical; 

some controls manufacturers specify 

the wire gauge, type, and shielding/ 

grounding requirements to prevent 

signal irregularities and errors. With 

wireless sensors, these considerations 

are not a concern, as data are transmitted over a Federal Communications 

Commission-approved frequency. The 

wireless sensors are self-powered and 

use on-board power management to 

alert the building operator when the 

battery needs to be changed. 

Most HVAC equipment suppliers are 

now offering systems designed to accommodate DCV and accept readings from 

CO2 sensors, so including CO2-based 

DCV in a new HVAC installation 

should not add significantly to the difficulty of getting the system into operation. However, retrofitting an existing 

system to work with DCV may be more 

problematic, particularly for an older 

system with pneumatic controls. 

The sensors typically are mounted on 

walls like thermostats. Some manufacturers offer thermostat/sensor combinations. Units that monitor temperature, 

CO2, and humidity are also available; 

they are useful with systems that include 

desiccant dehumidification to control 

the humidity load in ventilation air. 

Data from the sensors are fed to the 

building’s HVAC control system or to 

an actuator that controls the amount of 

ventilation air that is admitted. In a 

retrofit installation, it may be necessary 

to repair or upgrade dampers so they 

will work in a more dynamic, modulating fashion in response to the sensors. 

Properly functioning dampers that can 

be automatically controlled are essential. Pneumatic controls will need to 

be replaced with electronic controls or 

DDCs; it may also be worthwhile to 

replace existing electronic controls with 

DDCs. Actuator modules that do not 

have input points for the sensors will 

need to be upgraded to add input points. 

Air handler unit and variable-air-volume controls are used for communication between the sensors and the air-handling system. 

Control Type Control Medium Sequence 

Pneumatic Air pressure from 3 to 15 psi Hard-piped: changes require additional 

hardware and physical modifications to 

the control air tubing 

Electronic Electronic signals from 2 to 10 V DC, 0 to 

10 V DC, 4 to 20 mA are the most common. 

Other signals are 3 to 9 V DC, 6 to 9 V DC, 

0 to 20 V phase cut 

Hard-wired: changes require additional 

hardware and physical modifications to 

the control wiring 

Direct digital control (DDC)— 

application-specific 

Electronic signals from 2 to 10 V DC, 0 to 

10 V DC, 4 to 20 mA are the most common. 

Other signals are 3 to 9 V DC, 6 to 9 V DC, 

0 to 20 V phase cut, and via wireless transmission to multi-protocol enabled gateways 

Programmed into an electronic controller 

that can be configured: some systems may 

need additional hardware to accomplish 

desired sequences 

DDC—programmable Electronic signals from 2 to 10 V DC, 0 to 

10 V DC, 4 to 20 mA are the most common. 

Other signals are 3 to 9 V DC, 6 to 9 V DC, 

0 to 20 V phase cut and via wireless transmission to multi-protocol enabled gateways 

Programmed into an electronic controller 

that can be reprogrammed to accomplish 

desired sequences 

10 — FEDERAL ENERGY MANAGEMENT PROGRAM 
The application of a CO2-based DCV 

strategy using ASHRAE 62 is more 

complicated than simply installing CO2 

sensors and using them to control 

dampers. In variable-air-volume systems, particularly, fairly complex calculations and control algorithms may 

be necessary to program the control 

system properly for DCV. 

DCV is compatible with economizers 

or other systems that can bring outdoor air into a building for cooling. 

Economizer operation overrides DCV 

when conditions favor economizer 

use. DCV used in conjunction with 

an enthalpy economizer (one regulated by relative humidity) probably 

will save more energy than DCV with 

a temperature-regulated economizer. 

Heat exchangers that transfer heat 

between supply air and exhaust air 

reduce the energy demand caused by 

large inflows of ventilation air; therefore, DCV may not reduce energy 

use in buildings with heat exchangers. 

Evaporative cooling systems may not 

benefit from DCV during the cooling season. 

Maintenance Impact 

Maintenance of the sensors themselves is not reported to be a problem. 

Although earlier sensor models had 

reliability problems, the literature 

generally reports that newer models 

typically are reliable and accurate. 

Manufacturers offer sensors that 

recalibrate themselves automatically 

and that are guaranteed not to need 

calibration for up to 5 years. However, 

it is recommended that calibration be 

checked periodically by comparing sensor readings during a several-hour period 

when the building is unoccupied with 

readings from the outdoor air. Many 

sensor models are able to sense calibration problems and alert maintenance 

personnel if they are malfunctioning. 

Some users report problems in getting the sensors calibrated initially. A 

hand-held monitor should be used to 

ensure that the installed sensors are 

measuring CO2 concentrations in their 

zones accurately. 

CO2-based DCV is a more sophisticated 

technology than many maintenance personnel are accustomed to, a building 

researcher noted. A facility with a welltrained staff who know how to maintain 

and troubleshoot controls is the best 

candidate for a CO2-based DCV system. 

Equipment Warranties 

The prospective user should ask potential suppliers, contractors, and installers 

about warranties for specific equipment 

models. Warranties for CO2 sensors 

vary widely among different manufacturers. Those reviewed offer warranty 

periods for parts and labor ranging 

from 90 days from the date of shipment 

to 5 years from the date of purchase. 

A warranty period of 12 to 18 months 

for parts and labor appears to be fairly 

common. Some sensors are guaranteed 

to remain calibrated for at least 5 years, 

and at least one manufacturer offers a 

lifetime calibration guarantee. 

Codes and Standards 

The use of CO2-based DCV is accepted 

in both ASHRAE 62 and the International Mechanical Code (IMC). The 

IMC is referenced by the Building 

Officials and Code Administrators 

International, the Southern Building 

Code Congress International, and the 

International Code Conference of 

Building Officials, which together 

establish the model code language 

used in local and state building codes 

through the United States. The commentary on IMC Section 403.1 states, 

“The intent of this section is to allow 

the rate of ventilation to modulate in 

proportion to the number of occupants. 

CO2 detectors can be used to sense the 

level of CO2 concentrations which are 

indicative of the number of occupants... 

and this knowledge can be used to estimate the occupant load in a space.” 

ASHRAE 62 recommends DCV for all 

ventilation systems with design outside 

air capacities of greater than 3000 ft3 

per inch serving areas with an average 

design occupancy density of more than 

100 people per 1000 ft2

. 

The California Building Standards Code 

was amended in June 2001 to require 

CO2-based DCV in some high-density 

applications during periods of partial 

occupancy. A proposed change to the 

Oregon Building Code (NR-HVAC-7) 

would require HVAC systems to include 

provision for DCV during periods when 

spaces are only partially occupied. 

Costs 

Costs for sensors have dropped by about 

50% over the last several years as the 

technology has matured and become 

more widely used. Sensors typically cost 

about $250 to $260 each, uninstalled. 

For a new system, the installed cost will 

generally be about $600 to $700 per 

zone. For a retrofit system, the cost 

will depend on what type of control 

system the building has. A controls 

contractor estimates installed costs for 

retrofit applications at from $700 to 

$900 per zone for systems with an 

existing DDC programmable controller and from $900 to $1200 per zone 

for systems with pneumatic, electronic, 

or application-specific DDCs. Installation costs for wireless systems are minimal beyond the cost of the actual sensor 

and gateway that can serve multiple 

sensor units. 

In addition to the installation of the 

sensors, other components such as 

variable frequency drives, control 

input and output hardware are often 

needed to control the whole building, 

incrementally increasing the overall 

installed project cost beyond just the 

sensor cost. 

Utility Incentives and Support 

No specific information was found 

regarding utility incentives that are in 

place for CO2-based DCV. Some states 

(e.g., California) are considering such 

an incentive program. Most electric 

and natural gas utility companies have 

rebate programs to promote energyefficiency technologies that result 

in overall improvement in building 

performance, and DCV systems would 

quality for incentives under some of 

those programs. 

FEDERAL ENERGY MANAGEMENT PROGRAM — 11 
DCV is one of the technologies that 

utilities might consider for financial 

incentives in working with federal customers through a utility energy service 

contract on energy-efficiency projects 

at federal sites. 

Technology Performance 

Field Experience 

Three building operators whose facilities have installed CO2 sensors for 

DCV and a controls engineer whose 

company oversees HVAC installations 

were contacted for this report regarding their experience with the use of 

CO2-based DCV. All were generally 

pleased with the performance they 

have observed, although one reported 

problems with getting the sensors properly calibrated and wired. 

Purdue University has installed CO2 

sensors in 12 large auditoriums and 

lecture halls (100 to 500 seats) to address 

both air quality issues and energy costs. 

The sensors were added to existing air 

handling systems, and modulating outside damper actuators were added where 

they were not already in place. The existing air-handling units were 15 to 50 years 

old. Some of the rooms had pneumatic 

dampers with electronic controls; those 

controls were not replaced unless they 

were in bad condition. The large auditoriums had DDC systems. All the 

existing control modules had enough 

available inputs to add the sensors. 

Purdue’s controls systems engineer 

reported that there were minor problems with retrofitting the older airhandling systems, but they were the 

same kinds of problems that would 

have surfaced with a conventional 

HVAC retrofit-a lack of original or 

updated building plans and plans that 

did not match the existing systems. 

“We had to do some legwork to verify 

the existing configurations. It would 

be easier with new systems,” she said. 

Purdue has found the equipment 

installed to be reliable, and it has performed as expected. There has been 

a negligible impact on the maintenance staff because the sensors installed 

recalibrate themselves automatically. 

Purdue had previously installed sensors 

from another manufacturer that proved 

unsatisfactory because they could not 

be calibrated properly or could not 

maintain their calibration, the controls 

engineer said. “The calibration issue 

is very important in sensor selection,” 

she said. The maintenance for the 

other equipment installed has been 

comparable to maintenance on the 

systems replaced. 

Once the sensors began operating, 

they revealed that some of the lecture 

rooms had been underventilated by 

the old systems. The sensors worked 

well in resolving IAQ issues. Purdue 

has not monitored energy use since 

the sensors and new dampers were 

installed, but trended data have shown 

that the ventilation dampers modulate 

to lower or minimal positions when the 

lecture rooms are unoccupied or partly 

occupied and on weekends. Before the 

sensors were installed, the dampers were 

open to ventilate for full occupancy during the occupied cycle time (6 A.M. 

to 10 P.M. weekdays and 8 A.M. to 

4 P.M. Saturdays). 

Purdue continues to install CO2-based 

DCV in new applications in large rooms 

with variable occupancy. It will be added 

in a renovation of the air handling system in a 900-person-capacity ballroom 

of the Purdue Memorial Union and is 

being reviewed for application in dining halls on campus. 

A CO2 sensor was installed in an office 

building on the Beaufort Marine Corps 

Air Station in South Carolina to regulate the makeup air system. It is the 

first of several DCV retrofits planned 

on the base as part of an energy services 

performance contract and a Marine 

Corps-funded controls system upgrade 

for the station. The air station is located 

in the low country of South Carolina, 

a particularly humid climate with a 

heavy cooling load. 

The office building, a one-story 

41,354 ft2

 facility with no windows, 

contains offices and a flight simulator. 

It was designed for 500 people, and 

the ventilation system supplied enough 

air to meet ASHRAE standards for 500, 

but the occupancy is rarely over 100, 

said Neil Tisdale, utilities director for 

the base. “That’s a lot of air to be conditioning for no reason.” The sensor 

was added as part of a makeup-airsystem retrofit. The system already 

had modulating dampers and DDCs. 

Adding CO2-based DCV was fairly 

simple—installing a sensor and modifying the control program to regulate 

the damper with input from the sensor. The CO2 sensor was placed in the 

return air path. 

The system has been operating for a 

year, Tisdale said, and he is not aware 

of any maintenance problems or malfunctions. He ventured a rough estimate that the DCV system reduces the 

cooling load for the building by 20 tons, 

saving roughly of 12 megawatt hours 

of power annually. The load for the 

building’s chiller, sized to provide cool 

air for 500 people, was reduced so 

much that part of the chilled water 

was diverted and used to cool an adjacent 11,000 ft2

 building. 

A large hospital in Houston, Texas, has 

installed CO2 sensors in its auditoriums 

to ensure good IAQ and control energy 

costs, according to the hospital’s manager of energy services. The sensors 

were added to existing systems, all of 

which had digital controls; integrating 

the sensors was not difficult, he said. 

The sensor input is not yet being used 

to control the dampers automatically; 

building staff are monitoring the sensors to see whether they will control air 

changes properly before switching to 

automatic control. “We’re going to take 

it a step at a time and expand gradually,” the energy services manager said. 

The switch to direct control of dampers by the sensors will take “minutes” 

to implement and will probably occur 

during the coming year, he said. 

12 — FEDERAL ENERGY MANAGEMENT PROGRAM 
When the hospital begin installing the 

sensors, it was discovered that about half 

of them were not wired properly and 

needed to be rewired, he said. Many 

of the units were calibrated incorrectly 

and had to be recalibrated using a handheld meter. “Some of them were showing 4000 to 5000 ppm of CO2. You 

can’t just set them up and assume they’ll 

work properly,” he cautioned. 

However, he expects the sensors and 

DCV to perform well now that the 

initial problems have been addressed. 

They may be added in other areas such 

as busy foyers and other gathering areas 

once the conference room installation 

is in full operation. 

The owner of a digital controls company 

who oversees HVAC installations says 

his company’s clients who have installed 

CO2-based DCV systems have been 

generally pleased with their performance 

and found DCV to be a valuable addition. A new HVAC installation that 

incorporates CO2 sensors and DCV is of 

minimal cost and difficulty and requires 

only a few additional calculations to set 

up the air handling program properly, 

he said. He cautions that sensors should 

be installed to cover every CO2 zone in 

an area because high occupancy, and a 

corresponding high CO2 level, in one 

zone may not be reflected in the sensor 

readings from the adjacent zone. 

Although his firm has not done formal 

studies of savings from DCV, it has seen 

a reduction in outside air requirements 

in all DCV installations because none 

of the facilities are at the design occupancy all the time. The largest energy 

savings are likely in buildings designed 

to meet ASHRAE 62 requirements, 

he said, because they are likely to be 

admitting more unneeded outside air. 

He notes that if a building has previously been chronically under-ventilated, 

installing DCV might increase rather 

than decrease energy usage because it 

would bring in more outside air. However, DCV will correct IAQ problems 

and reduce liability for IAQ-related 

illnesses in such situations and may correct problems with mold growth. 

The maintenance impact of installing 

CO2 sensors is usually minimal if the 

sensors are self-calibrating, he said. 

Sensor calibration can be checked periodically by comparing indoor sensor 

readings with metered outside air readings after a building has been unoccupied for about 5 hours. 

Energy Savings 

None of the building operators interviewed had measured energy consumption before and after the installation of 

CO2 sensors. However, both Purdue staff 

and the controls company owner have 

observed lower outside air requirements 

in facilities using DCV, which generally 

results in reduced energy demand. 

Maintenance Impact 

The maintenance impact of installing CO2 sensors has been minimal 

at Purdue. The sensors used are selfcalibrating and have performed reliably. 

The hospital in Texas reported problems 

with getting several of the sensors calibrated initially and had to use hand-held 

monitors to recalibrate them. In addition, some of the sensors were wired 

improperly and had to be corrected. 

Case Study 

This case study describes the methodology used to assess the cost and energy 

savings implications of retrofitting a 

building for CO2-based ventilation control. This methodology can be applied 

to any building that has a track record 

of energy usage. In this case, the preliminary assessment of the building 

showed significant energy savings were 

available. The performance of the building after 6 months of operating with 

CO2 control is also presented and shows 

that the predicted performance was 

slightly conservative compared with 

the actual savings realized. 

Facility Description 

This case study addresses a privately 

owned (non-government) 30-story 

Class A office building in Birmingham 

that was retrofitted with a CO2-based 

ventilation control system in 2001. It 

had an existing state-of-the-art digital 

building control system installed several 

years earlier that was fully functional. 

The building was also upgraded to 

qualify for the EnergyStar label awarded 

by EPA to buildings having met qualifying energy efficiency standards. 

Utility costs for the building were very 

low, $0.48/kWh during the base year 

of 1999; overall energy costs for the base 

year were $1.61 ft2

/year, representing 

117,992 Btu/ft2

/year. This energy performance was compared with that of 

other similar buildings in that region 

using the DOE Energy Information 

Administration (EIA) energy intensity 

indices, which provide a general guide 

to average energy usage for different 

types of buildings in a region. The case 

study building was found to consume 

about 30% more than those found in 

the EIA indices. The fact that the energy 

cost was higher than average provided 

some preliminary indication that despite 

the low utility costs and EnergyStar 

rating, there were some opportunities 

for further energy conservation. 

Of the total energy consumed by the 

building in the year 2000, 84.55% 

was spent on electricity for a total of 

13,966,500 kWh or $670,742 annually; 

the maximum peak load was 3,318 kW. 

Of the remaining total energy consumed 

by the building, 13.81% was spent on 

steam for a total of 7,810,000 lb at a 

cost of $122,581 annually. 

Existing Technology 

Description 

The building HVAC system was 

designed with two air-handling units 

(AHUs) per floor, located on opposite 

sides of the building. Variable air volume (VAV) boxes served interior zones, 

and linear diffusers were located on 

perimeter zones. The linear diffusers 

have re-heat capability; the interior VAV 

boxes do not. Each AHU fan motor 

was controlled by a variable-frequency 

drive (VFD) to supply VAV boxes on 

the floor. Each AHU was on a time-ofday schedule provided by the automation system, wherein the units were 

FEDERAL ENERGY MANAGEMENT PROGRAM — 13 
scheduled on and off to correspond 

with the staff occupancy for that particular floor on a Monday through 

Friday basis, with limited Saturday 

hours of operation. Sunday was most 

often scheduled off all day for most 

floors. Because of the nature of the client operations, a few floors operated 

24 hours per day, 7 days per week. 

Outside air is drawn into each AHU at 

each floor through a ducted grille. The 

combined general building and bathroom exhaust are provided by twin fans 

(of differing sizes) exhausted at the roof 

level by connecting all floors through 

twin vertical shafts. Both exhaust 

fans were of a constant-speed design, 

exhausting the full design load air 

regardless of the intake of outside air 

into the building. Although a limited 

number of floors operated 24 hours 

per day, both exhaust fans ran constantly at the full design load. This 

feature probably also contributed to 

the higher than normal operating cost 

for the building. 

The building had a DDC building air 

system that was deemed capable of 

executing a DCV strategy with some 

additional programming, and had sufficient input/output capacity to add 

the required components (e.g., CO2 

sensors, peripheral I/O modules). 

New Technology Equipment 

Selection 

The building automation system (BAS), 

an existing Siemens System 600, had 

been installed several years previously. 

It was deemed capable of accepting the 

data from the new CO2 sensors, able to 

execute the new control strategy, and 

to have sufficient spare point capacity 

to provide the required input/output 

(I/O) from/to the new devices. Four 

new Telaire series 8002, dual-beam CO2 

sensors were installed per floor, except 

on the second floor, which had a number of enclosed meeting/conference 

rooms. One CO2 sensor was installed 

in each of these rooms. One outside 

CO2 sensor was installed to provide 

accurate indoor/outdoor CO2 differential readings.To facilitate the additional 

I/O point requirements, new modules 

were installed within each S600 cabinet. 

For the CO2 sensors, analog input modules accepting a 4-20 mA signal were 

needed, for the new fully proportional 

electric actuators, replacing the old relay 

(open/closed) actuators required analog modules driving a 0-10 V signal. 

The existing building exhaust fans were 

retrofitted with Magnatek VFDs to balance the aggregate total of outside-air 

intake. The Magnatek VFDs were specified with factory-installed Siemens S600 

FLN (field level network) cards to facilitate the connection to the S600 BAS 

without having to ‘hardwire’ each I/O 

point into the S600 control cabinet; this 

arrangement saved labor and the expense 

of individual I/O modules while simultaneously providing much more motor 

performance data to the building owner. 

Completing the BAS component 

changes were the addition of one 

Setra building static pressure sensor 

that was essential to ensure a positive 

pressure in the whole building relative 

to the outside. 

No other major control components 

were required for the case study building; however, the application of a new 

and fairly complex control strategy was 

essential to execute the DCV application. The DCV control algorithm is 

the most critical aspect of the project, 

as failure to implement an effective 

control sequence will yield lower energy 

savings performance. 

Building Upgrade Assessment 

Building owners must be able to evaluate the energy-saving potential and 

cost of specific initiatives to weigh 

the value of various building upgrade 

options. The methodology used to 

assess the potential of CO2-based ventilation control involved five basic steps. 

1. Spot measurement of CO2 levels 

2. Trend logging of CO2 and other 

environmental factors 

3. Estimation of the savings potential 

4. Implementation assessment 

5. Payback analysis 

1. Spot measurement of CO2 

As indicated previously, CO2 concentrations can be correlated to cfm/person 

ventilation rates inside a space. For a preliminary assessment of ventilation rates 

for this building, a number of spot measurements of CO2 concentrations were 

made on each floor. A hand-held CO2 

monitor was used that is capable of calculating the cfm/person ventilation rate 

based on inside/outside differential CO2 

concentrations. The monitor assumes 

outside concentrations are 400 ppm, 

but it will also allow the baseline concentration to be set based on an actual 

outside measurement. 

Spot measurements for CO2 were made 

in the mid-morning to late morning and 

late afternoon hours on weekdays, after 

occupancy had stabilized in the building. They were taken while the building 

was not operating in economizer mode. 

The results of the spot measurements 

showed that most areas of the building 

under study had CO2 concentrations 

below 700-800 ppm, corresponding 

to ventilation rates in the range of 

28 to 35 cfm/person. These rates were 

well over the original design target of 

20 cfm/person. The chart shows the 

correlation between peak CO2 levels 

Figure 5. Handheld CO2 sensor with cfm/ 

person calculation and data logging. 

14 — FEDERAL ENERGY MANAGEMENT PROGRAM 
Courtesy of Telaire

Courtesy of Telaire

and cfm/person ventilation rates, assuming office-type activity and an outside 

level of 400 ppm. Based on the spot 

measurements, it appeared that this 

building could be a good candidate for 

energy savings through better control 

of ventilation. These results warranted 

further investigation. 

2. Trend logging of environmental 

factors 

Trend logging was conducted over 

7 typical days in the building to ensure 

that representative conditions were 

being measured. Ideally, measurements 

should be made in the major occupancy 

zones on each floor. If many locations 

are involved and monitoring devices are 

limited, multiple measurement sessions 

may be necessary. Devices used for 

measurement should measure CO2 and 

should be able to log concentrations to a 

CO2 & Ventilation 

cfm/person CO2 

Under 

Ventilated 

Ideal 

Over 

Ventilated 

Outside air 

5 

10 

15 

20 

25 

30 

35 

40 

50 

100 

2500

1500

1200

1100

1000

900

850

800

750

700

650

600

500

400

Figure 6. CO2 to ventilation rate conversion, 

assuming 400 ppm outside and office-type 

activity (1.2 MET). 

Nov 2000 

database every 15 minutes for a period 

of a week (at least 672 data points per 

parameter measured). Typically, datalogging sensors come with software to 

adjust, download and graph the results. 

Several locations in the building were 

monitored over 7 days. Results of trend 

logging verified that the building was 

over-ventilated compared with the 

original design. The ventilation rate 

can be determined by looking at portions of the graph that show extended 

periods of operation where the CO2 

levels have stabilized; these indicate 

that the amount of CO2 produced by 

people has reached equilibrium with 

the ventilation rate of the space. These 

periods are represented by the flat areas 

at the peak of each of the daily trend 

logs. In almost all locations, CO2 levels 

and calculated ventilation rates were 

similar to those recorded during spot 

measurements. In general, peak levels 

around 930 ppm indicate a ventilation 

rate of 20 cfm/person; peak levels near 

1100 ppm would indicate ventilation 

rates of 15 cfm/person. At the peak 

values recorded in the chart (674 ppm 

on average), the effective delivered 

amount of fresh air per person was more 

than 34 cfm/person, or 170% of the 

design need of 20 cfm/person. During 

periods of lower occupancy throughout 

the day and during Saturday morning 

operation, the effective delivered cfm/ 

person considerably exceeded design needs 

and resulted in the use of excess energy 

to condition the surplus outside air. 

Over-ventilation in the space may be 

due to either space densities being below 

original design conditions or the upward 

adjustment of outside air delivery to the 

building over design conditions. The 

building operator indicated that during 

summer months, occupants in the 

building often complained of uncomfortable humidity levels, indicating that 

perhaps the existing system was introducing more outside air than the system was originally designed for. This 

often happens when building operators 

“tweak” the building control system or 

air intakes to respond to complaints or 

to better tune the “feel” of the building. 

Based on hundreds of measurements 

in buildings throughout the country, 

over-ventilation appears to be a common problem in office buildings. 

Figure 7. CO2 trend-logged results from 7 days of monitoring of one location in the building. 

FEDERAL ENERGY MANAGEMENT PROGRAM — 15 
3. Savings potential/pre-project 

energy analysis 

A number of CO2 sensor manufacturers 

offer software to analyze the cost savings 

that will result from applying a CO2 

ventilation control based on occupancy 

versus a strategy of fixed ventilation during all occupied hours. These programs 

typically use local hourly weather data 

and energy cost data. They focus on the 

energy required to heat and cool various quantities of outside air delivered 

to the building without undertaking a 

full-blown energy performance analysis 

of the building. A similar analysis can be 

performed using more elaborate building analysis programs such as DOE2. 

Using one manufacturer’s CO2 software, 

the case study building was modeled 

floor-by-floor to assess the potential 

annual energy savings. Ventilation rates 

determined from the trend logging were 

used to calculate the current fixed ventilation rate by multiplying the cfm/ 

person of ventilation air by the typical 

peak occupancy on the floor observed 

during the trend-logged period. For 

CO2 control, the modeling program 

assumed a control algorithm that would 

proportionately modulate air delivery 

based on the CO2 concentration, a typical ventilation control strategy used with 

CO2 sensing. It also allowed for simulated occupancy patterns to be varied 

every 30 minutes to reflect typical occupancy variations through the day. The 

program correlates the hourly ventilation 

load with hourly normalized outdoor 

temperature and dewpoint climactic data 

to provide an accurate assessment of 

Summary of projected energy savings from CO2 

Energy Electricity Steam Total 

kWh Costa ($) Therms Costb 

Base 13,966,500 670,800 147,756 122,591 793,391 

With CO2 12,513,896 601,075 134,758 111,023 712,098 

Savings 1,452,604 69,725 12,998 11,568 81,293 

Savings (%) 10.4 8.8 10.2 

a Electricity cost = $0.48 per kWh. 

the HVAC load during all hours while 

accounting for days when economizer 

operation results in zero savings as a 

result of the ‘“free cooling” effect. 

For the case study building, the CO2 

modeling program projected that annual 

savings of excess of $81,293 would be 

achievable based on normalized climatic 

data. Based on energy costs in 2000, 

these savings are equivalent to a 10% 

reduction in total energy costs, an 

average of $3000 in savings per floor 

annually, and $0.22 per square foot 

of gross area per year. 

4. Implementation assessment 

Most floors in the building had open 

floor plans, with perimeter offices in 

some cases. In most cases, office doors 

remained open during occupied hours, 

allowing free flow of ventilation air 

between the open central area and the 

offices. For these floors, it was decided 

to place one CO2 sensor on the wall in 

each quadrant of the building. The 

rationale for such spacing was that each 

sensor would cover an area of no greater 

than 3600 ft2

 of open floor, and two sensors would provide input to each AHU. 

To ensure that all spaces were adequately 

ventilated, the ventilation is controlled 

based on the highest (or worst-case) level 

of the paired CO2 sensors. It is important to note that duct sensors were not 

used because they tend to reflect an average ventilation rate rather than what is 

actually occurring in the space. 

One of the floors had a large number 

of enclosed meeting/training/videoconferencing rooms that were not often 

control 

all occupied at the same time. One CO2 

sensor was installed in each of those 

rooms. In many instances, inter-zonal 

transfer of air from spaces with lower 

CO2 levels will moderate the amount 

of outside air that must be delivered 

to the floor, particularly if all rooms 

are not occupied. 

The AHU on each floor required that the 

relay-operated outside air damper actuator be replaced with a fully modulating 

electrical motorized actuator to allow 

modulation of air delivery to each floor. 

To alleviate the constant negative pressure relationship in the building, the 

original building static pressure sensor 

located at the highest point within 

the building (in the elevator shaft, for 

unknown reasons) was disconnected. 

A new building static pressure sensor 

was located off the lobby level, on the lee 

side of the building and of the prevailing winds to minimize false positive or 

negative readings. For the twin exhaust 

fans, VFDs were added to balance the 

outside air intake with the required 

exhaust while maintaining a positivepressure relationship with the outside. 

The new outside air CO2 sensor was 

installed on the roof, away from any 

building exhaust and the effects of 

street-level fluctuations in CO2. 

Critical tasks a building control system or a supporting control and logic 

system must be able to perform for 

CO2 control include these: 

• Take input from a number of CO2 

sensors on a floor and determine 

the highest level. 

• Modulate a signal to an actuator or 

variable-speed fan serving each floor 

to proportionally modulate the delivery of air based on the CO2 concentration measured on the floor. 

• Control the central building air 

intake so demand to the entire 

building can be modulated based 

on the demand of each floor. 

(Often a pressure sensor in the 

main supply air trunk can ensure b

 Steam cost = $0.89 per therm (natural gas source @81% efficiency). adequate air delivery.) 

16 — FEDERAL ENERGY MANAGEMENT PROGRAM 
In summary, the work required to 

upgrade the building included 

• Installing a minimum of four CO2 

sensors and two VFD drives on 

each of the air intakes for each floor 

and interfacing these devices to the 

building control system. 

• Programming the building control 

system to take the CO2 transmitter 

signal and regulate air delivery on each 

floor based on in-space CO2 levels. 

• Moving and replacing the building 

static pressure sensor. 

• Installing variable-speed drives on 

the building exhaust fans. 

It is important to note that for CO2 

control to work in a building, all other 

HVAC-related systems must be in good 

operating order. CO2-related investigations may identify problems not previously recognized and add cost to an 

upgrade project. In this building, the 

assessment identified problems with 

the location of the building pressurization sensor, which had to be relocated 

and replaced. Logging of CO2 concentrations in the spaces also indicated 

that the time-of-day operating schedules 

on some floors did not match actual 

occupancy patterns, and a change was 

recommended. In some cases, a regular 

check of logged CO2 data from permanently installed sensors can help keep 

time-of-day schedules relevant to current 

occupancy patterns. In some cases, CO2 

data have been used to detect end-ofday occupancy and initiate setback 

operation when inside levels approach 

outside concentrations. 

5. Payback analysis 

The total cost of the building upgrade, 

including equipment and labor, was 

estimated at $178,800, which also 

included $15,000 for the for the preproject trend analysis. Based on the 

projected cost savings of $81,293 the 

CO2 upgrade project was projected to 

yield a 2.2-year payback. Based on this 

Summary of BLCC 5.1-03 life-cycle cost analysis 

Study Period 15 years


Discount Rate 3%


Initial Investment: Cash 

 Requirements 

Future Cost 

Annual & non-annual 

 recurring cost 

Energy related cost 

Total 

Base: Current


Operational/No


CO2 Control


$ 

$ 

$9,414,476 

$9,414,476 

Retrofit of Self 

Calibrating Saving from 

CO2 Control CO2 

$178,800.00 $ (178,800.00)

$ $

$8,460,875 $953,602 

$8,460,875 $953,602 

$953,602 

$178,800 

5.33 

15.66% 

3 years 

3 years 

Net Savings 

PV of non-investment savings 

Increased total investment 

Savings-To-Investment Ratio 

Adjusted Internal Rate of Return 

Simple Payback 

Discounted Payback 

methodology and analysis, the project 

was initiated by the building owner in 

the late spring of 2001 and completed 

in July of that year. 

Life-Cycle Cost Analysis 

A life-cycle cost analysis of this project 

using BLCC 5.1-03 was performed 

using energy and cost data for the building collected for the year 2000 but based 

on an April 2003 start date, as required 

by the BLCC program. This procedure 

probably results in an analysis based on 

slightly lower costs in the analysis than 

prevail currently. The study period of 

15 years was selected because this is the 

typical life of most electronic control 

devices. If a longer period is desired, the 

user should account for replacement 

of the sensors at the end of year 15 

(approximate cost is $250 to $350 per 

replacement sensor, including labor). 

In performing the CO2 portion of the 

study, no annual or periodic costs were 

assumed. In this case, we assumed use 

of self-calibrating sensor that require 

no maintenance or calibration over their 

operating life. Some sensors do require 

periodic calibration at 3 to 5 years, and 

users are urged to consider this fact in 

the selection and cost analysis of their 

particular installation. The cost of 

calibration will vary depending on the 

manufacturer and procedures required. 

About a third of the sensors sold today 

have a self-calibrating feature that eliminates maintenance requirements. 

The total cost of the building upgrade, 

including equipment and labor, was 

estimated at $178,800 (including 

$15,000 for pre-project trend analysis). The projected annual cost savings 

was $81,293. The upgrade project was 

projected to yield a 2.2-year payback. 

Post-Implementation Experience 

After 6 months of operation, energy 

data from the building were collected 

to determine how the CO2 retrofit and 

other improvements to the building 

were performing. Unfortunately, because of changes resulting from a company reorganization, a full 12 months 

of performance data was not available 

for analysis. Figure 6 provides a summary of the energy usage for each halfyear period during 2000 and 2001. 

The CO2 ventilation control system 

was operated from July to December 

of 2001. As can be seen from the data, 

the reductions in energy consumption 

FEDERAL ENERGY MANAGEMENT PROGRAM — 17 
variance

Monthly Totals

Courtesy of Telaire

were in excess of the savings predicted. 

The difference is probably due to a 

number of factors, including these: 

• Replacement and relocation of 

the building pressurization sensor 

probably impacted energy savings, 

but savings were not predicted for 

this improvement. 

• Time-of-day schedules were reprogrammed based on actual occupancy, 

and building exhaust fans were 

adjusted to minimum levels during 

unoccupied hours. The change that 

probably contributed additional 

energy savings to savings predicted. 

• The year 2001 was milder than 

2000 and had 20% fewer cooling 

degree days and 4% fewer heating 

degree days. 

According to the facility manager, the 

tenants were satisfied with the comfort 

levels in the space following the retrofit 

and no longer complained of high 

humidity levels in the building during 

summer months. Because the logged 

CO2 data showed the space to be significantly over-ventilated, reducing 

ventilation with CO2 control reduced 

the amount of humid outside air drawn 

into the building and allowed the cooling system to maintain better control 

of humidity. 

The following charts show energy performance, electricity costs, and steam 

costs before and after the CO2-based 

DCV retrofit. 

Before-and-after energy performance 

*CO2 Control in Operation 

Energy Cost 2000 

Jan–June July–Dec 

2001 

Jan–June July–Dec* 

Electricity kwh 

Electricity ($) 

6,357,000 

$305,136 

7,609,500 

$365,256 

6,606,000 

$317,088 

6,219,000 

$298,512 

Steam (therm) 

Steam ($) 

71,918 

$64,007 

75,838 

$67,496 

84,523 

$75,225 

22,960 

$20,434 

Total ($) 

Annual ($) 

$369,143 $432,752 

$801,895 

$392,313 $318,946 

$711,260 

6 month savings comparing July–Dec 2000 vs 2001 

Electric ($) 

Steam ($) 

Total ($) 

$66,744 

$47,061 

$113,805 

Figure 8. Shown are the monthly costs (right scale) for the ‘baseline’ months 2000 

(light line) and for the months of 2001 (dark line) calculated using 2000 rates. The variance (left scale) is shown by the columns. A major vector change occurred beginning 

in July (as the first phases of DCV were coming on-line) that is known not to be weather 

related (the minor variance in Feb/Mar is known to reflect a shift in the weather load). 

18 — FEDERAL ENERGY MANAGEMENT PROGRAM 
variance

Monthly Totals

Courtesy of Telaire

Figure 9. Shown are the monthly costs (right scale) for the ‘baseline’ months in 2000 

(lighter line) and the cost for the months of 2001 (darker line) calculated using 2000 

rates. The variance (left scale) is shown by the columns. Since July, savings have 

occurred each month as a direct result of the CO2 retrofit project, whereas the variance 

in March 2001 is known to be due to a shift in weather load. 

Before and After Steam Usage for Case Study Building 

The Technology 

in Perspective 

The Technology’s Development 

CO2-based DCV is an emerging technology with currently limited but 

increasing market penetration. The 

literature on CO2-based DCV consistently predicts that the technology will 

become a common ventilation strategy. 

CO2 sensors for DCV regulation are 

a relatively mature product, having 

been on the market since about 1990. 

The first CO2 sensors were expensive, 

unreliable, and difficult to keep calibrated. However, manufacturers claim 

to have resolved those problems—units 

currently available generally are selfcalibrating and similar to thermostats 

in price and reliability. Although manufacturers say most sensors are designed 

to operate for 5 years without maintenance, regular inspection to verify 

calibration and proper operation is 

still recommended. 

Interest in DCV was spurred by 

ASHRAE 62, which increased the 

requirement for ventilation air in 

buildings to safeguard IAQ. Building 

managers became concerned that the 

increased ventilation level was driving 

up energy costs by introducing unnecessarily large amounts of fresh air that 

had to be cooled, heated, dehumidified. 

CO2-controlled DCV offers a method 

of regulating ventilation levels so as to 

satisfy the requirements of ASHRAE 

62 without over-ventilating. 

DCV based on CO2 sensing is recognized as a viable strategy by the HVAC 

and building industries: 

• CO2 sensors are sold by all major 

HVAC equipment and controls 

companies. 

• More than a dozen manufacturers 

produce CO2 sensors for DCV. 

• Most manufacturers of thermostats 

and economizers now integrate CO2 

sensors into their products, and major 

manufacturers of packaged rooftop 

HVAC systems offer factory-installed 

CO2 sensors as an option. 

• ASHRAE 90 requires CO2 sensors 

for DCV in high-density applications. 

• In the next revision of its building 

code, California will begin requiring 

CO2-based DCV in all buildings 

housing 25 people or more per 

1000 ft2

. 

• A proposed change in the Oregon 

building code would require DCV 

for HVAC systems with ventilation 

air requirements of at least 1500 cfm, 

serving areas with an occupant factor of 20 or less. 

• ASHRAE Standard 62, the IMC 

(which establishes minimum regulations for mechanical systems), and 

some state and local building codes 

recognize CO2-based DCV. 

• The U.S. Green Building Code gives 

points in its LEED rating system for 

use of CO2-based DCV. 

Technology Outlook 

CO2-based DCV appears likely to 

become a commonplace ventilation 

strategy for large commercial and institutional buildings as building operators 

seek ways to balance building code 

ventilation requirements and IAQ concerns with the need to control energy 

demand and operating costs. Equipment development is encouraging the 

adoption of the technology. Prices of 

CO2 sensors for DCV prices have 

dropped by about 50% since 1990, 

FEDERAL ENERGY MANAGEMENT PROGRAM — 19 
and as market penetration increases, 

are expected to fall further. Most HVAC 

equipment makers are including factory 

installation of CO2 sensors for DCV 

as an option in their large packaged systems. At least one major manufacturer 

has adapted its equipment line to 

accommodate CO2-based DCV in 

every piece of ventilation equipment 

it makes. This implicit endorsement of 

the technology by equipment makers 

makes its adoption simpler and less 

expensive, at least in new installations, 

and will almost certainly contribute 

to developing a broader market for 

CO2-based DCV. 

The emergence of wireless, self-powered 

multi-parameter (CO2/temperature/ 

humidity) sensors designed for permanent installation is expected to further 

increase the speed of adoption of DCV. 

They have the potential to lower the 

total cost of deployment, making 

installation simpler and faster and 

improving paybacks. 

As installers, HVAC engineers, and 

maintenance personnel accumulate 

more hands-on experience with the 

controls and operational issues CO2­

based DCV presents, and gain more 

expertise in troubleshooting and resolving problems, the comfort level with 

the technology should increase. The 

increased familiarity is likely to increase 

its acceptance. 

Manufacturers 

The following list includes companies 

identified as manufacturers of CO2 sensors for demand-controlled ventilation 

at the time of this report’s publication. 

The list does not include manufacturers of CO2 sensors designed for use in 

safety equipment or for control of conditions in laboratories or industrial 

processes that are not appropriate for 

demand-controlled ventilation. We 

made every effort to identify all manufacturers of the equipment, including 

an extensive search of the Thomas 

Register; however, this listing is not 

purported to be complete or to reflect 

future market conditions. 

AirTest Technologies 

1520 Cliveden Avenue 

Delta, BC V3M 6J8 

Tel: 888-855-8880, 604-517-3888 

Fax: 604-517-3900 

www.airtesttechnologies.com 

mike.schell@airtesttechnologies.com 

Carrier Corporation 

6304-T Thompson Rd., P.O. Box 4808 

Syracuse, NY 13221 4808 

Tel: 315-432-6000 

www.carrier.com/ 

DetectAire, Inc. 

5973 Encina Road, Suite 109 

Goleta, California 93107 

Tel: 805-683 1117 

www.detectaire.com 

(DetectAire markets wireless sensors) 

Digital Control Systems, Inc. 

7401-T S.W. Capitol Hwy. 

Portland, OR 97219 2431 

Tel: 503-246-8110 Fax: 503-246-6747 

http://www.dcs-inc.net 

Honeywell Control Products 

11 W. Spring St. 

Freeport, IL 61032 

Tel: 815-235-6847 Fax: 815-235-6545 

Cable: Honeywell-Freeport 

http://www.honeywell.com/sensing 

Johnson Controls, Inc. 

Controls Group 

507 E. Michigan St., P.O. Box 423 

Milwaukee, WI 53201 0423 

Tel: 800-972-8040 Fax: 414-347-0221 

Kele 

3300 Brother Blvd. 

Memphis, TN 38133 

Tel: 888-397-5353 Fax: 901-382-2531 

Email: info@kele.com 

www.kele.com 

MSA 

MSA Bldg., P.O. Box 426 

Pittsburgh, PA 15230 0426 

Tel: 412-967-3000 

Fax: 412-967-3450 or 800-967-0398 

Cable: MINSAF 

http://www.msanet.com 

Telaire Systems, Inc. 

6489 Calle Real, Dept. TR 

Goleta, CA 93117 

Tel: 805-964-1699 Fax: 805-964-2129 

Texas Instruments, Inc. 

Commercial Sensors & Controls Div. 

34 Forest St., MS 20-22, P.O. Box 2964 

Attleboro, MA 02703-0964 

Tel: 800-788-8661, Ext. 400 

http://www.tisensors.com 

Thermo Gas Tech 

8407 Central Ave. 

Newark, CA 94560 

Tel: 888-243-6167 Fax: 510-794-6201 

Or call: 510-745-8700 

http://www.thermogastech.com 

Vaisala, Inc. 

100 Commerce Way 

Woburn, MA 01801 1008 

Tel: 800-408-5266 Fax: 781-933-8029 

http://www.vaisala.com 

Tel: 503-598-4564 Fax: 503-598-4664 

http://www.veris.com 

Who is Using 

the Technology 

Federal Sites 

The Pentagon 

Robert Billak 

Department of Defense 

Pentagon Heating and Refrigeration Plant 

300 Boundary Channel Dr. 

Arlington, VA 22020 

Navy Annex 

Robert Billak 

Department of Defense 

Pentagon Heating and Refrigeration Plant 

300 Boundary Channel Dr. 

Arlington, VA 22020 

Beaufort Marine Corps Air Station 

Neil Tisdale, Utilities Director 

Beaufort, South Carolina 

Non-Federal Sites 

Purdue University 

Luci Keazer, P.E. 

Facilities Service Department 

1670 PFSB Ahlers Drive 

West Lafayette, IN 47907 

Lkeazer@purdue.edu 

Oberlin University 

Adam Joseph Lewis Center 

for Environmental Studies 

Leo Evans 

122 Elm Street 

Oberlin, Ohio 44074 

Reedy Creek Energy Services 

(The Walt Disney Company) 

Paul Allen 

407-824-7577 

paul.allen@disney.com 

Shorenstein Reality Services 

Bob Landram 

816-421-4997 

blandram@shorenstein.com 

20 — FEDERAL ENERGY MANAGEMENT PROGRAM 

16640 SW 72nd Ave.

Portland, OR 97224 

Veris Industries, Inc. 
For Further Information 

Associations 

American Society of Heating, Refrigerating and Air-Conditioning Engineers 

American Society for Testing and Materials 

U.S. Green Building Council 

American Indoor Air Quality Council 

Design and Installation Guides 

Demand Controlled Ventilation System Design, Carrier Corporation, Syracuse, NY, 2001


Application Guide for Carbon Dioxide Measurement and Control, Telaire Corporation, Goleta, California, 1994.


Manufacturer’s Application Notes 

“Reference Guide for Integration CO2 DCV with VAV Systems,” Telaire Corporation, 

October 2000. www.telaire.com/telaire.htm. 

“Common CO2 Wiring Issues,” Telaire Corporation, October 2000, www.telaire.com/telaire.htm. 

Publications 

A.T. DeAlmeida and W.J. Fisk, Sensor-Based Demand Controlled Ventilation, LBNL-40599, UC-1600, Lawrence Berkeley 

National Laboratory, July 1997.* 

M.J. Brandemuehl and J.E. Braun, “The Impact of Demand-Controlled and Economiser Ventilation Strategies on Energy 

Use in Buildings,” ASHRAE Transactions, vol. 105, pt. 2, pp. 39–50, American Society of Heating, Refrigerating and AirConditioning Engineers, Atlanta, 1999.* 

M.J. Brandemuehl and J.E. Braun, “The Impact of Demand-Controlled Ventilation on Energy Use in Buildings,” p. 15, 

paper RAES99.7679 in Renewable and Advanced Energy Systems for the 21st Century, RAES 1999 Proceedings, R. Hogan, 

Y. Kim, S. Kleis, D. O’Neal, and T. Tanaka, eds., American Society of Mechanical Engineers, New York, 1999.** 

S.C. Carpenter, “Energy and IAQ impacts of CO2-Based Demand-Controlled Ventilation, ASHRAE Transactions, vol. 102, 

pt 2., pp. 80–88, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, 1996.** 

S.J. Emmerich and A.K. Persily, “Literature Review on CO2-Based Demand-Controlled Ventilation,” ASHRAE Transactions, vol. 103, pt. 2, pp. 229–243, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, 

1997.* 

Electric Power Research Institute, Office Complexes Guidebook, Innovative Electric Solutions, TR-109450, October 31, 1997. 

W.J. Fisk and A.T. DeAlmeida, “Sensor-Based Demand Controlled Ventilation: A Review,” Energy and Buildings, 29(1) 

(March 1), 1998.** 

S. Gabel and B. Krafthefer, Automated CO2 and VOC-Based Control of Ventilation Systems Under Real-Time Pricing, 

EPRI-TR-109117, Electric Power Research Institute, Palo Alto, California, and Honeywell Technology Center, Minneapolis, 

Minnesota, October 1998.**

 D. Houghton, “Demand-Controlled Ventilation: Teaching Buildings to Breathe,” E Source Tech Update TU-95-10, E 

Source, Boulder, Colorado, 1995.* 

D.B. Meyers, H. Jones, H. Singh, P. Rojeski, “An In situ Performance Comparison of Commercially Available CO2 Sensors, 

pp. 45–53 in Competitive Energy Management and Environmental Technologies: Proceedings, Association of Energy Engineers, Atlanta, 1995. ** 

B.A. Rock and C.T. Wu, “Performance of Fixed, Air-side Economizer, and Neural Network Demand-Controlled Ventilation 

in CAV Systems, ASHRAE transactions, vol. 104, pt 2., pp. 234–245, American Society of Heating, Refrigerating and AirConditioning Engineers, Atlanta, 1998. 

* Publication that provided information for this document. 

** Publication retrieved from NISC/BiobliLine. 

FEDERAL ENERGY MANAGEMENT PROGRAM — 21 
K.W. Roth, D. Westpalen, J. Dieckmann, S.D. Hamilton, and W. Goetzler, Energy Consumption Characteristics of Commercial Building HVAC Systems Volume III: Energy Savings Potential, TIAX 68370-00, TIAX, LLC, Cambridge, MA, July 2002.* 

M.B. Schell and D. Inthout, “Demand Control Ventilation,” ASHRAE Journal, American Society of Heating, Refrigerating 

and Air-Conditioning Engineers, Atlanta, February 2001.* 

M.B. Schell, S.C. Turner, and R.O. Shim, “Application Of CO2 Demand-Controlled Ventilation Using ASHRAE 62: Optimizing Energy Use And Ventilation,” ASHRAE Transactions, vol. 104, pt. 2, pp. 1213-1225, American Society of Heating, 

Refrigerating and Air-Conditioning Engineers, Atlanta, 1998.* 

M. Schell, “Real-Time Ventilation Control,” Heating, Piping, Air-Conditioning Engineering, Interactive Feature, April 

2002.* www.hpac.com/member/feature/2002/0204/0204schell.htm 

Case Studies 

Adam Joseph Lewis Center for Environmental Studies, www.oberlin.edu/envs/ajlc/ (Building Systems, Heating and Air 

Quality, Indoor Air Quality) 

Codes and Standards 

Ventilation for Acceptable Indoor Air Quality, ASHRAE Standard 62-2001, American Society of Heating, Refrigerating and 

Air-Conditioning Engineers, Atlanta. www.ashrae.org. 

Energy Standards for Buildings Except Low-Rise Residential Buildings, ASHRAE Standard 90.1-2001, American Society of 

Heating, Refrigerating and Air-Conditioning Engineers, Atlanta. www.ashrae.org. 

American Society of Testing and Materials Standard D6245-98, Standard Guide for Using Indoor Carbon Dioxide Concentrations 

to Evaluate Indoor Air Quality and Ventilation 

2000 International Mechanical Code, International Code Council, Falls Church, Virginia. 

2001 California Building Standards Code, Title 24, California Code of Regulations, Part 4: California Mechanical Code, 

California Building Standards Commission, Sacramento, California. 

22 — FEDERAL ENERGY MANAGEMENT PROGRAM 
Appendix A


Federal Life-Cycle Costing Procedures and the BLCC Software 

Federal agencies are required to evaluate energy-related investments on the basis of minimum life-cycle costs (10 CFR Part 436). 

A life-cycle cost evaluation computes the total long-run costs of a number of potential actions, and selects the action that minimizes the long-run costs. When considering retrofits, sticking with the existing equipment is one potential action, often called 

the baseline condition. The life-cycle cost (LCC) of a potential investment is the present value of all of the costs associated with 

the investment over time. 

The first step in calculating the LCC is the identification of the costs. Installed Cost includes cost of materials purchased and the 

labor required to install them (for example, the price of an energy-efficient lighting fixture, plus cost of labor to install it). Energy 

Cost includes annual expenditures on energy to operate equipment. (For example, a lighting fixture that draws 100 watts and 

operates 2,000 hours annually requires 200,000 watt-hours (200 kWh) annually. At an electricity price of $0.10 per kWh, this fixture has an annual energy cost of $20.) Nonfuel Operations and Maintenance includes annual expenditures on parts and activities 

required to operate equipment (for example, replacing burned out light bulbs). Replacement Costs include expenditures to replace 

equipment upon failure (for example, replacing an oil furnace when it is no longer usable). 

Because LCC includes the cost of money, periodic and aperiodic maintenance (O&M) and equipment replacement costs, energy 

escalation rates, and salvage value, it is usually expressed as a present value, which is evaluated by 

LCC = PV(IC) + PV(EC) + PV(OM) + PV(REP) 

where PV(x) denotes “present value of cost stream x,” 

IC is the installed cost, 

EC is the annual energy cost, 

OM is the annual nonenergy O&M cost, and 

REP is the future replacement cost. 

Net present value (NPV) is the difference between the LCCs of two investment alternatives, e.g., the LCC of an energy-saving 

or energy-cost-reducing alternative and the LCC of the existing, or baseline, equipment. If the alternative’s LCC is less than the 

baseline’s LCC, the alternative is said to have a positive NPV, i.e., it is cost-effective. NPV is thus given by 

NPV = PV(EC0

)– PV(EC1)) + PV(OM0) – PV(OM1)) + PV(REP0)– PV(REP1)) – PV(IC) 

or 

NPV = PV(ECS) + PV(OMS) + PV(REPS) – PV(IC) 

where subscript 0 denotes the existing or baseline condition, 

subscript 1 denotes the energy cost saving measure, 

IC is the installation cost of the alternative (note that the IC of the baseline is assumed zero), 

ECS is the annual energy cost savings, 

OMS is the annual nonenergy O&M savings, and 

REPS is the future replacement savings. 

Levelized energy cost (LEC) is the break-even energy price (blended) at which a conservation, efficiency, renewable, or fuelswitching measure becomes cost-effective (NPV >= 0). Thus, a project’s LEC is given by 

PV(LEC*EUS) = PV(OMS) + PV(REPS) – PV(IC) 

where EUS is the annual energy use savings (energy units/yr). Savings-to-investment ratio (SIR) is the total (PV) savings of a 

measure divided by its installation cost: 

SIR = (PV(ECS) + PV(OMS) + PV(REPS))/PV(IC). 

Some of the tedious effort of life-cycle cost calculations can be avoided by using the Building Life-Cycle Cost software, BLCC, 

developed by NIST. For copies of BLCC, call the EERE Information Center (877) 337-3463. 

FEDERAL ENERGY MANAGEMENT PROGRAM — 23 
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24 — FEDERAL ENERGY MANAGEMENT PROGRAM 
About FEMP’s New Technology Demonstrations


The Energy Policy Act of 1992 and subsequent Executive Orders mandate that 

energy consumption in federal buildings 

be reduced by 35% from 1985 levels by 

the year 2010. To achieve this goal, the 

U.S. Department of Energy’s Federal 

Energy Management Program (FEMP) 

sponsors a series of activities to reduce 

energy consumption at federal installations nationwide. FEMP uses new technology demonstrations to accelerate 

the introduction of energy-efficient and 

renewable technologies into the federal 

sector and to improve the rate of technology transfer. 

As part of this effort, FEMP sponsors 

the following series of publications that 

are designed to disseminate information 

on new and emerging technologies: 

Technology Focuses—brief information 

on new, energy-efficient, environmentally friendly technologies of potential 

interest to the federal sector. 

Federal Technology Alerts—longer 

summary reports that provide details on 

energy-efficient, water-conserving, and 

renewable-energy technologies that have 

been selected for further study for possible implementation in the federal sector. 

Technology Installation Reviews—concise reports describing a new technology 

and providing case study results, typically from another demonstration program or pilot project. 

Other Publications—we also issue other 

publications on energy-saving technologies with potential use in the federal sector. 

More on Federal 

Technology Alerts 

Federal Technology Alerts, our signature 

reports, provide summary information 

on candidate energy-saving technologies developed and manufactured in the 

United States. The technologies featured 

in the FTAs have already entered the market and have some experience but are 

not in general use in the federal sector. 

The goal of the FTAs is to improve the 

rate of technology transfer of new energysaving technologies within the federal 

sector and to provide the right people in 

the field with accurate, up-todate information on the new technologies so that 

they can make educated judgments on 

whether the technologies are suitable for 

their federal sites. 

The information in the FTAs typically 

includes a description of the candidate 

technology; the results of its screening 

tests; a description of its performance, 

applications, and field experience to date; 

a list of manufacturers; and important 

contact information. Attached appendixes 

provide supplemental information and 

example worksheets on the technology. 

FEMP sponsors publication of the FTAs 

to facilitate information-sharing between 

manufacturers and government staff. 

While the technology featured promises 

significant federal-sector savings, the FTAs 

do not constitute FEMP’s endorsement 

of a particular product, as FEMP has not 

independently verified performance data 

provided by manufacturers. Nor do the 

FTAs attempt to chart market activity 

vis-a-vis the technology featured. Readers should note the publication date on 

the back cover, and consider the FTAs 

as an accurate picture of the technology 

and its performance at the time of 

publication. Product innovations and 

the entrance of new manufacturers or 

suppliers should be anticipated since the 

date of publication. FEMP encourages 

interested federal energy and facility 

managers to contact the manufacturers 

and other federal sites directly, and to 

use the worksheets in the FTAs to aid 

in their purchasing decisions. 

Federal Energy Management Program 

The federal government is the largest energy consumer in the nation. Annually, the total primary energy consumed by the federal 

government is 1.4 quadrillion British thermal units (quads), costing $9.6 billion. This represents 1.4% of the primary energy consumption in 

the United States. The Federal Energy Management Program was established in 1974 to provide direction, guidance, and assistance to federal 

agencies in planning and implementing energy management programs that will improve the energy efficiency and fuel flexibility of the 

federal infrastructure. 

Over the years, several federal laws and Executive Orders have shaped FEMP’s mission. These include the Energy Policy and Conservation 

Act of 1975; the National Energy Conservation and Policy Act of 1978; the Federal Energy Management Improvement Act of 1988; the 

National Energy Policy Act of 1992; Executive Order 13123, signed in 1999; and most recently, Executive Order 13221, signed in 2001, and 

the Presidential Directive of May 3, 2001. 

FEMP is currently involved in a wide range of energy-assessment activities, including conducting new technology demonstrations, to hasten 

the penetration of energy-efficient technologies into the federal marketplace. 
A Strong Energy Portfolio for a Strong America 

Energy efficiency and clean, renewable energy will mean a stronger economy, a cleaner 

environment, and greater energy independence for America. Working with a wide array 

of state, community, industry, and university partners, the U.S. Department of Energy’s 

Office of Energy Efficiency and Renewable Energy invests in a diverse portfolio of 

energy technologies. 

Log on to FEMP’s Web site for information 

about New Technology Demonstrations 

www.eere.energy.gov/femp/ 

You will find links to 

•	 A New Technology Demonstration Overview 

•	 Information on technology demonstrations 

•	 Downloadable versions of publications in Adobe Portable 

Document Format (pdf) 

•	 A list of new technology projects under way 

•	 Electronic access to a regular mailing list for new products 

when they become available 

•	 How Federal agencies may submit requests to us to assess 

new and emerging technologies 

For More Information 

EERE Information Center 

1-877-EERE-INF or 

1-877-337-3463 

www.eere.energy.gov/femp 

General Program Contacts 

Ted Collins 

New Technology Demonstration 

Program Manager 

Federal Energy ManagementProgram 

U.S. Department of Energy 

1000 Independence Ave., SW EE-92 

Washington, D.C. 20585 

Phone: (202) 586-8017 

Fax: (202) 586-3000 

theodore.collins@ee.doe.gov 

Steven A. Parker 

Pacific Northwest National Laboratory 

P.O. Box 999, MSIN: K5-08 

Richland, WA 99352 

Phone: (509) 375-6366 

Fax: (509) 375-3614 

steven.parker@pnl.gov 

Technical Contact and Author 

James R. Sand 

Oak Ridge National Laboratory 

P.O. Box 2008, Bldg. 3147 

Oak Ridge, TN 37831-6070 

Phone: (865) 574-5819 

Fax: (865) 574-9329 

sandjr@ornl.gov 

Produced for the U.S. Department 

of Energy, Energy Efficiency and 

Renewable Energy, by Oak Ridge 

National Laboratory 

DOE/EE-0293 

March 2004