Building a business
Save on summer cooling bills
Heating, ventilation, and cooling accounts for roughly half the
energy consumed in school buildings and homes. It pays to examine
your use of HVAC systems to control costs and ensure health
As a first step, gather utility bills for the past 12 to 24 months. Make a
graph, with dollar amount on the left and months across the bottom. Notice
when costs are highest and lowest. When might you turn off HVAC systems and
open windows? File the graph to use as a benchmark in analyzing savings.
Look at the building
Many child care operations have little control over the buildings they use.
They may be old or poorly designed, and remodeling can be expensive and complex.
Even so, you can take some simple and low-cost steps toward energy efficiency.
The most common HVAC systems are central air systems. They force cooled air
(heated air in winter) through ducts in a continuous loop through the building.
A cooling system consists of 1) a compressor or condensing coil outside and
2) an air handler or evaporating coil on the inside. The two are connected
by tubes that carry a refrigerant.
Indoors the conditioned air loops from the air handler through the indoor space
and back to the air handler. Every time air passes through the air handler,
it loses heat to the refrigerant. The heat is released to the condensing unit
The HVAC system may also have a built-in ventilation mechanism to allow an
occasional intake of fresh air. A damper, or mechanical valve, opens whenever
the air handler runs or by a timer.
Know the location of your inside units and all supply and return air grills.
Be sure there is good air flow around the compressor outside. You might erect
a wire fence to keep children away from it, but don’t enclose it in a
box or plant anything within 3 feet of it. The heat coming out needs room to
Check for air leaks. Caulk the holes around outlets, wires, and pipes. Make
sure doors and windows close tightly, are well caulked, and have adequate weatherstripping.
Check ducts leading into the air handler and at other accessible locations.
Consider installing exterior solar screens. These screens, attached to outside
window frames, can save up to a third on summer heating bills. They are less
expensive than awnings and more effective than interior blinds or shades because
they prevent heat from getting inside. They can be removed in winter or anytime
Prepare for the summer
HVAC systems will run better and last longer if they are properly
maintained. Arrange for yearly HVAC service in the spring.
A technician should:
clean the air fins and the condensing and evaporating coils,
check the compressor’s electrical load (amperage draw),
oil the fan motors and check belts,
check the damper operation,
check thermostats and recalibrate if necessary, and
check operating pressures and temperatures to ensure they comply
with the manufacturer’s recommendations.
Control for comfort
Feeling comfortable depends on several factors, not just the
air temperature but also relative humidity and air movement.
Humidity. The cooling system goes on or off according to changes in temperature.
The system also reduces humidity as it runs. But most systems don’t start
lowering humidity until after they’ve been running about 10 minutes.
So if you live in a hot, humid climate, the run cycle should last long enough
to lower both the temperature and the humidity.
Unfortunately many buildings and homes have large systems that cool the air
quickly and then shut off. The air is cool but if the humidity is high, you
may still feel clammy. Furthermore, if the humidity rises above 60 percent,
molds grow, which could make people sick.
A properly sized unit is large enough to cool the space in a reasonable time
and small enough to run in long cycles so it has time to dehumidify the air.
By running longer cycles, the system runs more efficiently and exerts less
strain on the compressor. And a smaller unit costs less to run.
You may not be able to do much about humidity until your cooling unit needs
to be replaced. When it does, make sure your HVAC contractor does a load calculation
to figure the right number of AC tons for your building. Also make sure the
AC unit carries an Energy Star label, which means it has met strict energy
efficiency guidelines set by the federal government.
setting. Many facilities set room thermostats at 78 degrees in summer
(and 68 degrees in winter). When the building is unoccupied, raise the thermostat
If the weather is hot and humid, however, turning off units is not advised.
When the space gets too hot, the unit may not be able to cool the space in
a reasonable time when you turn it back on. More important, a humidity above
60 percent will promote mold growth.
Consider installing programmable thermostats. These cost $50 to $200 each,
but are well worth the cost in energy savings. Your HVAC technician can install
and program the thermostats to fit your schedule. Make sure teachers know how
to operate them, however, so they can adjust the setting for a night or weekend
Air movement. Consider installing ceiling fans. They don’t actually make
the air cooler, but the moving air makes people feel cooler. Prices start at
$50 and vary by size and style. Fans cost about the same to run as a 100-watt
light bulb. Clean fan blades at least once a year.
Change filters often
AC filters pick up dust, pollen, and other particles. A dirty
filter impedes air flow and diminishes air quality. Left for
too long, a dirty filter can clog the blower and cooling coil
and cause it to wear out prematurely.
Determine which filters are best for your needs. Do children and staff have
respiratory problems such as allergies and asthma? Is your building next to
a highway or construction site? If you care for children in your home and have
pets, pet dander and hair could be a problem.
Look for the filter’s MERV rating (Minimum Efficiency Reporting Value).
This tells you the filter’s ability to capture particles between 3 microns
(the size of a human hair) and 10 microns on a scale of 1 to 16. The higher
the number, the better. The cheapest filers capture only larger particles of
10 microns or more, such as pollen and dust mites. Pleated media filters, by
contrast, capture smaller particles of 3 to 10 microns, such as mold spores.
Check filters every month. Establish a schedule for changing them, and appoint
a person to be responsible for the task. Cheaper filters need to be changed
For more information
Austin Energy Green Builder Program. Fact sheets. www.ci.austin.tx.us/greenbuilder/fs_toc.htm/.
Princeton Energy Resources International. August 2004. School
Operations and Maintenance: Best Practices for Controlling Energy
Costs. Prepared for U.S. Department of Energy. Available at Alliance
to Save Energy, http://www.ase.org/content/article/detail/1806/.