Q. My old central air conditioner works, but I want to install one that provides better comfort and lower electric bills. I am willing to pay some extra for the best. What are my options among 2002 models?
A. I normally don't recommend replacing an appliance before it fails, but central air conditioners may be an exception. Installing a new one can save so much electricity, it makes sense from economic and environmental standpoints, not to mention the increased comfort it provides.
At seasonal energy efficiency ratios (SEER) as high as 18, you can expect your electric bills for air-conditioning to be 50 percent less than your current bills. With the improved comfort and more temperature stability, you may be able to set your thermostat a little higher and save even more.
If the initial cost of the central air conditioner is not a problem for your budget, installing one of the two-output-level models is your best choice for comfort. Also, its higher efficiency may often provide the best long-term economic payback even with its higher initial cost.
Two-level air conditioners automatically adjust their cooling output to the cooling needs of your house. This offers several benefits. It operates at an efficient low-output-level when it is moderately warm outdoors, which is most of the time.
When outdoor temperature rises and extra cooling is needed to stay comfortable, the air conditioner switches to high-output level. This often happens during midafternoon. It may also switch to the high level when you are cooling a lot or having a party with many people creating indoor heat.
A key comfort advantage of a two-level model is it operates for a longer time on the low level. This keeps the air gently circulating to maintain very even room temperatures. If you have problems with allergies, it also controls the humidity level better and makes an air cleaner more effective.
Another comfort and efficiency advantage with a two-level model is its variable-speed blower motor. It automatically adjusts its speed to provide the proper air flow for varying cooling needs. With its unique design, this motor uses about 75 percent less electricity than a standard motor.
Another air-conditioning option for excellent comfort is a one-output-level model coupled with a variable-speed blower. This is what I use in my own house. If you also install a thermidistat-type thermostat at the same time, the variable-speed blower can help provide precise humidity control.
The newest and most efficient models use R410A refrigerant instead of older Freon, which destroys the Earth's ozone layer. Some R410A models tend to operate quieter too.
Q. I have a work shed in the back yard. It has a shiny metal roof, but it still gets very hot inside when I work out there. Will it help much to put foil under the roof since it is already metal?
A. This is difficult to answer without seeing your roof. Just because the roof is metal does not mean it rejects the sun's heat. Touch the roof on a bright sunny day. If the roof is hot then foil will help.
The purpose of putting foil underneath a hot roof is not to reflect the heat, but to create a radiant heat barrier between the hot roof and your body.
XWrite for Update Bulletin No. 867 which gives a buyer's guide of the 18 most efficient one- and two-level central air conditioners listing cooling outputs, SEERs, comfort features, warranties and a savings chart. Please send $3 and a business-size SASE to James Dulley, The Vindicator, 6906 Royalgreen Drive, Cincinnati, Ohio 45244. For an instant download, visit James Dulley online at www.dulley.com.