Member 2003
Energy Efficiency and
Indoor Air Quality in Schools
Overview
Indoor Air Quality
Tools for Schools

CHANGE FOR THE
BETTER WITH
ENERGY STAR
In the 1998-99 school year, U.S. K-12 public schools provided instruction to over 46 million
students. An estimated 70% of all school buildings have indoor air quality (IAQ) problems,
leading to an unhealthy environment.1 Because children breathe a greater volume of air
relative to their body weight Compared to adults, they may be more sensitive to indoor air
pollution. Additionally, occupants of school buildings are close together, with approximately four
times the occupant density in schools compared to office buildings. A 1995 CAO study2 reports
that ventilation, indoor air quality, temperature (heating and cooling), and lighting are among the
leading unsatisfactory environmental conditions in school buildings. Because mounting evidence
indicates that the quality of a school's physical environment affects educational achievement,
increased attention to both energy efficiency upgrades and indoor air quality in schools could
provide Significant benefits.
Many energy efficiency upgrades, can improve the quality of schools' indoor environment,
protecting and even enhancing IAQ without sacrificing energy performance. However, if certain
energy upgrades are not done correctly, they may adversely impact indoor air quality. Increased
energy efficiency in building construction, for example, has resulted in tighter building shells and
reduced ventilation rates.
This document describes how to protect
and enhance both indoor air quality and
energy efficiency. For further information
on improving school energy performance,
please refer to the ENERGY STAR®
Building Manual, available for download
in the Tools & Resources section at
www.energystar.gov/bu ild i ngs. For
guidance on indoor air quality, consult the
Indoor Air Quality Tools for Schools Kit
(see page 5 for contact information).
t
Common IAQ
Culprits
Many factors interact to create an unhealthy
indoor environment. The most important
include indoor pollutants, outdoor pollutants
near the building, pollution transport through
the ventilation system, air cleaning or filtration,
and indoor climate (temperature and relative
humidity). Many building materials, the
furnishings and equipment, and the occupants
and their activities are sources of indoor
pollution. Following is a list of some of the
more common pollutants and their sources.
¦ Environmental Tobacco Smoke (ETS):
Lighted cigarettes, cigars, pipes.
m Biological Contaminants (mold, bacteria,
viruses): Wet or damp materials, cooling
towers, humidifiers, cooling coils or drain
pans, damp duct insulation or filters,
condensation, wet carpet or ceiling tiles,
sanitary exhausts, bird droppings,
cockroaches or rodents, people with
contagious viruses.
1	Productivity Benefits Due to Improved Air Quality, Dorgan
Associates (1995), p.3.7.
2	School Facilities: Condition of America's Schools, United States
General Accounting Office, February 1995.

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Volatile Organic Compounds (VOCs):
Paints, stains, varnishes, solvents,
pesticides, adhesives, wood preservatives,
waxes, polishes, cleansers, lubricants,
sealants, dyes, air fresheners, fuels, plastics,
copy machines, printers, tobacco products,
perfumes, dry cleaned clothing, marking
pens, art supplies.
Formaldehyde: Particle board, plywood,
cabinetry, furniture, carpets, fabrics.
Soil gases (radon, VOCs, sewer gas,
methane): Soil and rock (radon), sewer
drain leaks, dry drain traps, leaking
underground storage tanks, land fills.
Pesticides: Termiticides, insecticides,
rodenticides, fungicides, disinfectants,
herbicides.
Particles (tiny solid particles or dust
particles in the air): Printing, paper
handling, smoking and other combustion
sources, outdoor sources of air pollution,
deterioration of materials, vacuuming,
construction/re novation, chalk.
Pollution transport
through ventilation.
Outside air also contains
contaminants that can be
brought inside through
the ventilation system.
Indoor air quality
problems caused by
outdoor pollutant sources
can stem from idling
school buses, local traffic
or vehicles at loading
docks, cooling towers for
the air conditioning system, sanitary or kitchen
exhausts, trash and landscaping chemicals
storage.
Air cleaning or filtration. Some contaminants
are removed from the air through natural
processes, when chemicals react with other
substances or settle onto surfaces. Removal
processes may also be deliberately
incorporated into the building through air
filtration devices. Standard filters protect
HVAC equipment from large particles, while
high-efficiency filters may collect some
breathable particles. Upgrading the filtration
system is commonly recommended as good
indoor air quality practice. However, ozone
generators sold as air purifiers can create
special problems and are not recommended.
Indoor climate/temperature and relative
humidity. Inadequate temperature and
humidity conditions affect indoor air quality for
several reasons. As temperature and relative
humidity increase, so does the rate at which
chemicals are released. Mold and dust mite
populations also increase with humidity levels.
In addition, students, teachers, or school staff
who are thermally uncomfortable may have a
lower tolerance to pollution exposures.
ASHRAE Standard 55-1992, Thermal
Environmental Conditions for Human
Occupancy, identifies many factors that
influence thermal comfort and conditions.
In most cases, maintaining a school within
the appropriate ranges of temperature and
relative humidity will meet thermal comfort
requirements.
How Energy
Efficiency
Projects Affect
IAQ
Many energy upgrades, such as those related
to fans, motors, drives, and chiller/boiler
systems, generally have little impact on IAQ.
Other energy efficiency measures are usually
very compatible with IAQ. Examples include
energy recovery (explained in a later section
of this document), which may reduce the
energy burden of outdoor air, especially in
extreme climates or when high outdoor air
volumes may be required (e.g., in schools,
auditoriums). Tune up/maintenance of the
HVAC system (e.g., clean coils/drain pans)
can at times improve IAQ by removing
contaminant sources. Finally, testing,
adjusting, and balancing the HVAC system
can improve ventilation effectiveness. The

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3
A Joint EPA Working Paper from ENERGY STAR® and Indoor Air Quality September 2003
Proportional Balancing Method reduces static
pressure and energy requirements better than
conventional balancing methods.
Some energy projects have the potential to
degrade IAQ, but can be made compatible
with appropriate adjustments. For example,
variable air volume (VAV) systems with fixed
outdoor air dampers tend to degrade IAQ
unless proper steps are taken.
Table 1 outlines the cautions and practical
steps that may be needed to avoid IAQ
problems for each energy efficiency measure.
The Energy
Cost of
Outdoor Air
Ventilation
The IAQ control most often associated with
high energy cost is the 15 cubic feet per
minute (cfm) per occupant outdoor air
requirement of ASHRAE Standard 62-1989.
An EPA study3 modeled a comprehensive
energy retrofit program and compared two
retrofitted buildings, one operating at 5 cfm
per occupant and one at 15 cfm per
occupant. Humidity was controlled in both
cases. Energy savings foregone to achieve
adequate ventilation ranged from 3 to 9% of
the pre-retrofit energy cost. Post-retrofit
results showed total energy savings of 22 to
41% at 5 cfm per occupant and between 19
and 37% at 15 cfm per occupant.
The study showed that relatively high energy
penalties during extreme weather conditions
were counterbalanced by energy savings
during milder weather, where the additional
outdoor air provided some "free cooling"
benefits. Free cooling is especially significant
in schools where high occupant densities
result in large internal heat gains, requiring
cooling even during cool weather.
Energy
Recovery
Ventilation
The high occupant densities of schools and
classrooms challenge building designers to
incorporate ventilation systems that provide
adequate outdoor fresh air. While
maintaining compliance with ASH RAE
Standard 62-1989, designers are also
interested in minimizing capital and
operational costs. Because increased outdoor
air ventilation rates can result in higher
heating and air-conditioning costs and more
indoor moisture problems in some geographic
locations, there is increased interest in energy
recovery ventilation (ERV) technology. ERV
systems transfer energy between the inlet and
exhaust streams as the building is being
ventilated. Some systems transfer only heat
energy, while others also transfer latent
(moisture) energy through a desiccant coating
or other means. Significant energy reductions
can be achieved by reducing the energy
requirements of conditioning the outdoor air,
particularly during extreme weather
conditions.
The total economic viability of ERV technology
depends on its impact on total costs. ERV
technology can lower capital costs by reducing
the peak loads, which in turn makes it
3 Hall, John D., Mudarri, David H., and Werling, Eric. Energy
Savings in Relation to Indoor Environmental Quality. In
Proceedings ofACEEE 1998 Summer Study on Energy Efficiency
in Buildings. 1998. American Council for an Energy-Efficient
Economy. Vol. 8, pp 99-110.

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4
Energy Efficiency and Indoor Air Quality in Schools
Table I: Energy Efficiency Measures Where Adjustments May Be Necessary
Measure
Comment
Improved building shell
(e.g., lights, office equipment)
If infiltration is reduced, may need to increase mechanically supplied
outdoor air to meet applicable ventilation standards.
Reduced internal loads
Reduced loads will reduce supply air requirements in VAV systems. May
need to increase outdoor air to meet applicable ventilation standards.
Air-side economizer
Uses outdoor air to provide free cooling. Can improve IAQ when
economizer is operating by helping to ensure that the outdoor air
ventilation rate meets IAQ requirements. On/off set points should be
calibrated to both the temperature and moisture conditions of outdoor
air (for example, by using an enthalpy controller) to avoid indoor
humidity problems. May need to disengage economizer during an
outdoor air pollution episode.
Variable Air Volume (VAV)
systems with fixed percentage
outdoor air
VAV systems can yield significant energy savings over Constant Volume
(CV) systems in many schools. However, many VAV systems provide a
fixed percentage of outdoor air (e.g., fixed outdoor air dampers), so that
during part-load conditions when the supply air is reduced, the outdoor
air may also be reduced to levels below applicable standards.
Night pre-cooling
Cool evening air pre-cools the building while simultaneously exhausting
accumulated pollutants. To prevent microbiological growth, controls
should stop pre-cooling if the dew point of outdoor air is high enough to
cause condensation on equipment.
C02 controlled ventilation
C02 controlled ventilation varies the outdoor air supply in response to
the C02 level, which is used as an indicator of occupancy. This may
reduce energy use for general meeting rooms, theaters, etc., where
occupancy is highly variable. The system should incorporate a minimum
outside air setting to dilute building-related contaminants during low
occupancy periods.
Reducing demand
(kilowatt) charges
Caution is advised when using night pre-cooling and sequential startup of
equipment to eliminate demand spikes if load-shedding strategies include
changing the space temperature set points or reducing outdoor air
ventilation during occupancy.
Reducing outdoor air ventilation
Applicable ventilation standards usually specify a minimum continuous
outdoor air flow rate per occupant, and/or per square foot, during
occupied hours. Reducing outdoor air flow below applicable standards
degrades IAQ, and is not recommended.
Reducing HVAC operating hours
Delayed start-up or premature shutdown of the HVAC system may
create IAQ problems and lead to occupant complaints. Insufficient lead
time prior to occupancy can cause thermal discomfort and pollutant-
related health problems if the HVAC system cannot sufficiently deal with
loads from both the nighttime setbacks and current occupancy. It may
be acceptable to shut down equipment before occupants leave if fans are
kept operating to ensure adequate ventilation.
Extending temperature
control setpoints
Some energy managers may be tempted to allow space temperatures or
humidity to go beyond the comfort range established by applicable
standards. This is not recommended, as occupant health, comfort and
productivity are compromised. The lack of overt occupant complaints is
NOT an indication of a healthy environment.

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5
A Joint EPA Vforking Paper from ENERGY STAR® and I ndoor Air Quality September 2003
possible to downsize equipment In some system
configurations, ERVs may further reduce costs by
eliminating the need for certain exhaust fans.
ERV systems, however, also entail certain
inefficiencies and pressure losses that reduce the
overall operating savings. I n addition, some
systems may require more maintenance, or may
incorporate additional filtration systems beyond
the ones required for the baseline system.
ERV systems are more economically viable in
extreme climates, particularly in hot and
humid climates where total energy recovery
systems are employed to reduce moisture-
related cooling loads. For example, in a
sample calculation for a prototypical
classroom wing of a school building with a
central air handling system in Miami, Florida,
a total energy recovery system achieved a
simple payback of 4 years for a 9-month
school year, but was reduced to less than
2 years for a 12-month operation with
afternoon and evening classes.
Summary
This document, particularly Table 1, describes
the precautions to take to prevent or resolve
indoor air quality problems related to energy
efficiency. This document was designed to
help facility managers create a healthier
indoor environment for students, teachers,
and staff. Increasing energy performance
through energy efficiency measures can not
only save energy and money, but also improve
the indoor air and comfort in school buildings.
Additional
Resources
The Indoor Air Quality Web site at
www.epa.gov/iaq provides information and
guidance on indoor air quality in homes,
schools, and commercial buildings. Many
documents can be downloaded, or you can
call the Indoor Air Quality Clearinghouse at
1-800-438-4318 (Fax 703-356-5386).
Information on how schools can start
implementing energy efficiency upgrades
can be found at the ENERGY STAR®
Web site atwww.energystar.gov/buildings.
Documents are also available from the
ENERGY STAR Hotline at 1-888-STAR-YES
(1-888-782-7937).

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