No reviewer tests or compares central air conditioners, nor does anyone evaluate long-term reliability. Consumer Reports published a "Brand Repair History" for furnaces in January, but has not done so for central air conditioners. (Note that ConsumerSearch has separate reports on room air conditioners and portable air conditioners that do recommend specific units.)
Central air conditioners need to be installed and connected to ductwork, and performance depends on the size and condition of your home, the climate where you live and other factors that make comparative testing impossible. Although no one tests central air conditioners, we found many helpful guides for choosing one. Experts say the major consideration -- even before brand -- is hiring a reputable contractor. The ACCA (Air Conditioning Contractors of America) website offers the best help for that. A printable worksheet includes questions to ask, and weights the importance of everything a contractor should do. You can score contractors and use the provided formula to determine the value of each bid relative to the work that will actually be performed (not all contractors do all of the recommended work). The American Council for an Energy-Efficient Economy also provides good advice for selecting a central air conditioning contractor, and recommends efficiency levels for new equipment.
FurnaceCompare.com has the most general information, including which brands make the most efficient central air conditioners. The site sells a downloadable guide with additional information, including wholesale prices of current models, but we found the free information here to be of more value.
Syndicated columnist and engineer James Dulley doesn't rate or compare central air conditioners, but he recommends many. He and his research staff evaluate designs and discuss them with the manufacturers' engineers. GreenGuide.com also recommends many untested central AC units based on specifications. If you want to minimize energy use for environmental reasons, GreenGuide.com is the best source. On the other hand, a majority of experts believes that you aren't likely to break even on the extra expense of a more efficient central air conditioner. It's analogous to buying a hybrid car: your cost of use will be lower, but you aren't likely to save enough money during the life of the product to offset the higher purchase price. Experts do say that if you are replacing an old inefficient central air conditioner, you can come out ahead in long-term cost. The government publishes a SEER (Seasonal Energy-Efficiency Rating) figure for all models, and some earn an ENERGY STAR designation. SEER is a comparative indicator of a central air conditioner's efficiency.
We interviewed many HVAC (an acronym for "heating, ventilating and air conditioning") contractors for our report on furnaces. These individuals also sell and install central air conditioners. We found comments by those experts to be helpful as well. We also read what other experts had to say on various websites, including AllExperts.com, HVAC-Talk.com and GardenWeb.com.
We found more criticism and complaints about Goodman (makers of the Goodman, Janitrol and Amana brands) than any other brand. In spite of that, most contractors maintain that the problem is not with Goodman products, which are sometimes less expensive, but with faulty installation. These pros say that other manufacturers, such as Trane and Bryant, establish stringent requirements for technicians who install their equipment, while Goodman will let anyone install one of their air conditioners. When these pros repair Goodman units, they often find that the problem is not defective or short-lived parts. If you buy a Goodman air conditioner from a skilled contractor, they say it will be as reliable as any other brand.