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Air Conditioning FAQs

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What is the most efficient thermostat setting for air conditioning?

The best setting is the highest temperature at which you are comfortable. We recommend 78 degrees when you're home and 80 degrees while you are away. As a rule, raising the thermostat setting just two degrees will reduce cooling costs by five percent.

When I replace my central air conditioner, would it be more efficient to get a larger unit? Will it make the house more comfortable?

It is best to get a properly sized unit. Although a larger unit may run for shorter periods of time, it will use more electricity due to its larger size. It may also fail to properly dehumidify the home. A properly sized unit will control both temperature and humidity, making the home more comfortable.

What does the "EER" or "SEER" rating on an air conditioner mean?

Both EER (Energy Efficiency Ratio) and SEER (Seasonal Energy Efficiency Ratio) are indicators of how efficient the unit is. The higher the number, the more efficient the unit and the lower the operating cost. SEER is used with central air conditioners, while EER is used with room air conditioners. For new central systems, SEERs of 12 or higher are generally considered high-efficiency units. For room units, EERs of 11 or higher are considered high-efficiency.

What is the recommended SEER rating for a central air conditioner?

The current minimum requirement is 10.0 SEER. This is significantly more efficient than older units. Ratings of 11.0 to 12.0 are common, and will have lower operating costs. Units with SEERs as high as 15 are available. The more you use your central air conditioning, the more you will benefit from higher SEER ratings, and the more likely that the additional cost will be offset by energy savings.

I have one room in my home that is always too hot in the summer. What can I do to make that room more comfortable?

If the room has a large area of exposed glass, keep curtains or blinds closed during daylight hours, particularly at times when the sun would shine directly in. You might also ask your air conditioning contractor to check whether you are getting enough air in that room. There may be a problem with your duct system.

Will ceiling fans help cool my home in summer, and should I run them constantly, even when my air conditioning is running?

Ceiling fans can help make the home more comfortable, either alone or in combination with your air conditioner, by creating more air movement, which makes the air feel cooler. But remember that they do not actually cool the air, so there is no point in running them in unoccupied rooms or when no one is at home.

What is a "whole-house fan" and is it a good option for cooling my home?

A whole-house fan is a large ventilating fan, typically mounted in a ceiling between the living space and attic. The fan draws air out of the living space and exhausts it to the attic, and then out through the attic vents. For the most effective ventilation, a window or windows in the lower part of the house should be partially opened, to bring cooler air into the home.