Conscious Choice: Air Conditioning: Replacement

August 1999 | Sensible Home

Air Conditioning: Replacement

by James Dulley

Dear Jim: Our 15-year-old central air conditioner still works, but it doesn’t keep all the rooms evenly cool and our electric bills are high. Is it wise to buy a new one? Should I get one of the new R410A models? — Al J.

Dear Al: Although each home is unique, in general you will be ahead financially in the long run by replacing a central air conditioner that is that old. A 50 percent savings on the cooling portion of your electric bills is reasonable to expect. You will also save because of fewer repair bills. The improvement in your comfort will be even more dramatic than your electric bill savings. By selecting the proper design and efficiency (highest is not always best) for your climate, you can have even cooling throughout your home. The humidity level can be precisely controlled, too. For the greatest comfort and lowest utility bills, select one of the two-stage (speed) compressor designs available.

Not all manufacturers offer these designs because they are more expensive to produce. These use special blowers (air handlers) that make your furnace more efficient, too. Ninety percent of the time, the compressor runs at a super-efficient slow or lower cooling output. It automatically switches to high output on only the hottest afternoons when extra cooling/dehumidifying capacity is needed. At the lower output, the special blower runs slower and is very quiet.

This improves comfort in two ways. First, it runs longer at the lower output to circulate the air better throughout your home. Second, with the room air moving more slowly past the cooling coils, more moisture is removed. This eliminates that muggy, yet cool, feeling common in many climates. Installing a new integrated thermostat/ humidistat is a perfect fit with a two-stage model. Both indoor and outdoor temperatures, plus the humidity level, determine when and how long the compressor and blower run.

If you choose a lower-cost single-stage air conditioner, select one with a scroll compressor. These are efficient, quiet and reliable. It has very few compressor parts that actually wear in over time. The efficiency of a single-stage air conditioner can be improved by replacing the indoor furnace blower unit with a variable-speed one. The comfort and efficiency from your furnace and the indoor air quality (for allergy sufferers) will also be improved in the winter.

R410A is new air conditioner refrigerant that is ozone-friendly as compared to common R22 freon, which will gradually be phased out. Several manufacturers already offer R410A models. The units operate at higher pressures, so they are built stronger and quieter. It is certainly worth considering one.

For a more in-depth evaluation of air conditioning systems, write for (or instantly download) Update Bulletin No. 908. It includes recommendations for the most efficient two- and single-level central air conditioners, output stages, SEER’s, comfort features, and warranties. A savings chart is also enclosed. Please include $3.00 and a business-size SASE, mailed to James Dulley, Conscious Choice, 6906 Royalgreen Dr., Cincinnati, OH 45244

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