Better-than-ever Air Conditioning

Q – Our noisy old central air conditioner is on its last legs and costs a lot to operate. I need a new one, but the sales hype is confusing. What is best for 1999 and is installing a new one a wise move?- Steve F.

A – There have been many improvements in central air conditioners. Some changes lower your utility bills, some improve your family’s comfort, and still others improve the environment.

Some models have SEERs (seasonal energy efficiency ratios) as high as 18. Compared to your old one at only 8 at best, your electric bills will be cut by more than half. In most cases, installing a new one is a wise financial decision even if your old one still works.

  The best and most efficient new models are much simpler. Gone are the complicated totally variable speed compressors of the mid-90s. They worked well, but were expensive. With better, computerized controls, the simpler two-speed and two-compressor models are as effective.

  For the best comfort and indoor air quality, lowest utility bills, and indoor/outdoor noise levels, a new multilevel cooling output model is an excellent choice. These top-end models may cost as much as 30 percent more than a typical single-level model, so you must consider both the lower utility bills and evaluate the value of the extra comfort.

  These multilevel output models operate at a super efficient lower-cooling output level most of the time. At this quiet low level, they run longer for better dehumidification and constant indoor temperatures. This makes them a good choice in areas where summer humidity is a factor. They only switch to the highest-output level on the hottest afternoons.

  For people with allergies, the fact that these models run at a lower output level is an advantage. With the central air conditioner and blower running longer, so does the central air cleaner.

  All of these multilevel models use special, efficient (ICM or ECM) blower motors indoors. The speed of these motors can be varied by the electronic controls so that the airflow is matched to the varying cooling needs of your house and compressor cooling output.

  These blower motors are designed to use much less electricity. This makes them ideal for continuous air circulation without driving up your electric bills too much. Another advantage is that these motors have soft-start controls. They slowly ramp up to full speed for quiet, no-draft (for winter heating also) air circulation too.

  Many of the reasonably priced, single-level models use scroll compressors without pistons and valves. There are very few moving parts inside and they actually wear in over time and operate better.

  Models with scroll compressors are reliable and quiet with efficiencies up to a SEER of 14. Installing one of these will still cut your electric bills significantly. For climates with steady summer weather conditions, these designs are ideal.

  Several models now use ozone-friendly R410A (called Puron by some manufacturers) refrigerant instead of freon. Current R-22 freon will eventually be phased out of use by law. There were two new ozone-friendly refrigerants being considered, but it appears that the R410A is the way that most manufacturers will go.