your home’s air conditioner or heat pump. Some tips that

should help save money and extend the life of the cooling

equipment follow.

The outdoor unit of the air conditioner contains a condensing

coil, a type of heat exchanger which depends on large

quantities of air flow to dump heat outside your home. Keep

this equipment clear of tall grass, leaves and other debris.

shrubs, or place the unit under a deck. Provide at least 2 feet

of clearance on all sides of the equipment and 5 feet of

clearance at the top.

Be certain that a clothes dryer is not vented within 10 feet of

the outdoor unit. The lint from the dryer will cling to the

condensing coil and lower the efficiency of the equipment and

its service life.

The condensing coil should be cleaned every year or so. This

cleaning is usually a part of a regular service contract. The coil

is easily accessible and must be chemically cleaned. If the fins

in the heat exchanger are bent, they should be straightened

with a comb.

The indoor coil, or evaporator coil, is located inside the

heat pump or air conditioner cabinet. All the air from the home

flows across this coil to be cooled in summer.

When air conditioning, the indoor coil is damp, attracts dirt

and can harbor mold and other contaminants. A dirty indoor

coil endangers your family’s health, wastes energy and cuts the

capacity of the cooling equipment.

Dirty indoor coils are notorious for reducing the air flow

through the equipment. For each 10% reduction in air flow, the

efficiency of the equipment drops about 5%. Reduced air flow

means less cooling and makes it difficult to maintain a house’s

comfort in hot weather.

The coil should be cleaned every few years, depending on

how often the system operates, the efficiency of the filter at

trapping dirt, and the airtightness of the ductwork. Leaky ducts

often draw in dirt which can accumulate on the indoor coil, so

seal the seams in your home’s ductwork.

Indoor coils are often dirty because they are hard to reach

and therefore seldom cleaned. Frequently a service technician

will have to cut into the ductwork in order to inspect the

indoor coil. The coil should be cleaned with a chemical

solution and a soft brush. Typically it takes a couple of hours

for a technician to clean the coil and may cost from $50 to

$200, depending on accessibility.

In addition to cleaning the indoor coil, have the technician

check the blower. Usually, the blower is readily accessible and

can be easily removed and cleaned.

To get the most out of your heat pump or air conditioner,

for the least cost, operate it efficiently. Start with the thermostat.

A higher setting saves money. Try keeping the room air

temperature at 80 to 85 degrees and using ceiling and room

fans to circulate the air to maintain comfort. Each degree you

raise the thermostat can save up to 5% on cooling costs. Any

time you will be away from the house for a few hours, be sure

to raise the thermostat setting. You will save money and it

should only take a few minutes for the cooling equipment to

bring the temperature back to a comfortable level after you

return.

Over 20% of your air conditioning bill can be due to

sunlight streaming through unshaded windows. Keep window

curtains drawn during the day to block sunlight. Keeping east

and west windows shaded is particularly important as they get

the most sunlight in summer.

Solar shade screens are another effective way to shade

windows. These fiberglass insect screens have a special weave

that blocks sunlight. They can be installed in standard screen

frames and must be placed on the outside of the window glass.

The shade screens are a little darker than conventional insect

screening. Some people appreciate the increased privacy they

offer.

Reducing moisture levels inside the home can save on

cooling costs and improve comfort. Air conditioners and heat

pumps dehumidify the air as well as cool it. Much of the

excess humidity inside the home comes from humid outdoor air

leaking inside. Sealing unwanted air leaks, such as around holes for

plumbing and wiring, helps lower interior moisture levels and reduce

air conditioning costs. For some houses, air leaks can contribute to

over 30% of cooling costs.

One easy way to determine if your air conditioner or heat

pump needs a tune-up is to check the difference in temperature

between the air exiting the supply ducts and that drawn into

the return ducts. You will need an accurate thermometer for

the test and to operate the cooling equipment for at least 15

minutes when the outdoor temperature is above 80 degrees.

While the unit is running, measure the temperature of the air at

a return and a supply register. These registers should be the

ones closest to the inside cooling equipment. The temperature

difference should be between 14 and 20 degrees. A smaller

difference indicates time for a service call.