How to Buy a Central Air Conditioner


What the best air conditioner has

  • High efficiency. An Energy Star qualified air conditioner will have a SEER of at least 14.5 and an EER of at least 12, while the most efficient central air conditioner will perform even better. Note, however, that air conditioner installation and the specific components used can effect efficiency. This means some models that nominally meet the Energy Star threshold might not qualify as installed.
  • Good value. A high-efficiency central air conditioner can seem expensive to operate in the beginning, but can be less costly in the long run, especially compared to older, less-efficient models. Government and utility company rebates are often available for models that meet high Energy Star standards or even higher CEE ones. Check these out before you buy as the savings can be substantial.
  • A solid warranty. For quality systems, 10 years is now the norm, though better systems have stronger warranties still. Some models offer lifetime coverage on the compressor; a significant consideration since that's the most important -- and costliest -- part of a central air-conditioner system.
  • Quiet operation. All central air conditioners are relatively quiet inside the home, but that doesn't meant they aren't stirring up a racket outside. If you have neighbors nearby, or like to sit outside even when the system is running, a quieter system will be appreciated by all.
  • Quality installers. Experts say that when you get to the bottom line, there isn't a whole lot separating the highest quality central air conditioner systems from the lowest. However, there is a big gulf between the highest quality installers and those that are less-qualified -- and that's the reason behind wide swings in customer satisfaction between brands; the best brands are very picky about who they let represent them in the field. Because of that, it might be a good idea to find the top installers servicing your area, and look then to the brands they represent when narrowing down your selections.

Know before you go

Do you have the necessary ductwork? If you're replacing an existing central air conditioner, then your house will already have a system of ducts in place. However, your contractor should still check out the ducts to make sure they are in good condition. Be sure to tell the contractor about any problems you are having with airflow or uneven cooling with your existing system, since this may be a sign of poorly designed ductwork. If you are adding a new air conditioner, you may be able to connect it to the ductwork for your central heating system, although it may need some modifications. If your home has no ductwork, you might want to consider a ductless mini-split system.

Consider your climate. If you live in a hot, humid climate, it's especially important to choose an air conditioner with a high SEER, since the air conditioner will be running a lot. In a hot, dry climate, EER is more important than SEER; it measures how effective the air conditioner will be in the hottest weather. In mild climates, consider a heat pump, which could meet your needs for heating as well as cooling. We discuss heat pumps in our separate report on furnaces.

Get at least three quotes from contractors. Regardless of the central air conditioner system you select, the difference between a great choice and a poor one often comes down to the contractor you select. Referrals from friends, neighbors and co-workers can be a good starting point. You can also ask local trade organizations for names of members in your area. Organizations like the Air Conditioning Contractors of America (ACCA) have directories on their websites that can be searched by ZIP code.

Get all the details. Don't trust a contractor who gives you an estimate based solely on your home's square footage. Make sure the contractor calculates your home's cooling needs according to Manual J, a tool published by the ACCA, and get a written estimate that shows all calculations, including ductwork design.

Check out the contractor's credentials. Ask to see the contractor's license and proof of insurance, and find out how long the company has been in business. recommends looking for a company whose technicians are certified by a trade organization, such as North American Technician Excellence (NATE) or HVAC Excellence. Get at least three references from each contractor, and be sure to check them. A check with your local Better Business Bureau is a good idea as well.

Buying tactics and strategies

Compare bids. Don't rely solely on price; you should expect to pay more for quality work. An extremely low bid is a warning sign that a contractor is likely to cut corners. The ACCA provides a handy guide on their website to compare bids based on both price and quality.

Negotiate for the best deal. An estimate isn't set in stone. If you have another bid that's lower, ask the contractor to explain the discrepancy. If you ask for a relatively small discount, you will probably get it. You can also negotiate for a better warranty or service contract.

Get it in writing. Make sure to get a written contract before the work begins. Project costs, scheduling, model numbers and warranty information should all be specified. This will protect you from unwanted last-minute changes.

Don't forget the rebates

Rebates come and go, and can vary by locality and power company, but when available, can help defray the cost of a new central air system. Check with your local authorities and energy companies to see what's currently available. A database of energy incentives and polices is also available here.