Energy Efficient Cooling Systems
Fast Facts
- Heating and cooling
("space conditioning") account for 50 to 70% of the energy
used in the average American home.
- In an average
air-conditioned home, air conditioning consumes more than 2,000 kilowatt-hours
of electricity per year, costing $1,350/year.
- Switching to high-efficiency air conditioners
and taking other actions to keep your home cool could reduce this
energy use by 20% to 50%.
- Air conditioners use about 5% of all the
electricity produced in the United States, at a cost to homeowners
of over $11 billion.
- Roughly 100 million tons of carbon dioxide is
released into the air each year from powering air conditioners--an
average of about two tons for each home with an air conditioner.
- The most efficient air conditioners on the
market are up to 70% more efficient than the typical room air
conditioners found in U.S. homes today.
- A combination of proper insulation,
energy-efficient windows and doors, day-lighting, shading, and
natural ventilation will keep homes cool on most days without
air conditioning.
- Window fans or a whole-house fan provide
effective means of exhausting the day's hot air during the night.
- A central air conditioning system will cool
your house more efficiently than room conditioners.
- When using a central sir conditioner, each
degree setting below 78°F will increase your energy consumption
and costs by approximately 8%.
What can I do to save energy in my home?
- Over most of the
cooling season, keep the house closed tightly during the day and ventilate
at night either naturally or with fans.
- If you only need
to cool a small portion of your house (for instance, your bedroom),
a room air conditioner may be the best choice.
- Reduce the cooling
load by effectively shading east and west windows and delaying heat-generating
activities, such as dishwashing, until the evening on hot days.
Central Air Conditioners
Choose a central air conditioner with a high Seasonal
Energy Efficiency Ratio (SEER). Look for the ENERGY STAR® label. See their web site for central air conditioners with SEER ratings of 12 or greater.
You can
lower your central air conditioner’s energy use by:
- Setting the
thermostat at 78°F or higher.
- Use bath and
kitchen fans sparingly when the air conditioner is operating.
- Inspect and
clean both the indoor and outdoor coils. Dirt build-up on the indoor
coil is the single most common cause of poor efficiency.
- Check the refrigerant
charge. If the system is overcharged or undercharged with refrigerant,
it will not work properly.
- Use the fan
only switch for nighttime ventilation to substantially reduce air-conditioning
costs.
Room Air
Conditioners
Room air conditioners
are labeled with their Energy Efficiency Ratio (EER). Look for units with
an EER of 10.0 or above. Check the ENERGY
STAR® web site for a qualifying brand.
Proper sizing is
very important for efficient air conditioning. An air conditioner generally
needs 20 Btu for each square foot of living space. The ENERGY STAR® web
site also includes a calculator for sizing your room air conditioner.
You
can lower your room air conditioners energy use by:
- Installing the
unit in a shaded spot on your home's north or east side. (Direct sunshine
on the unit's outdoor heat exchanger decreases efficiency by as much
as 10%.)
- Set the fan
speed on high, except on very humid days.
- Consider using
an interior fan in conjunction with your window air conditioner to
spread the cooled air more effectively through your home without greatly
increasing electricity use.
- At the start
of each cooling season, inspect the seal between the air conditioner
and the window frame to ensure it makes contact with the unit's metal
case.
- Check your unit's
air filter once a month and clean or replace filters as necessary. Keeping the filter clean can lower your air conditioner's energy
consumption by 5% to 15%.
Additional
Sources of Information
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