• Don’t hire a contractor who wants to size your unit based solely on the floor area of your house.
• Even though it will cost more initially, buying a higher efficiency unit saves money in the long run.
• Different models have different abilities to handle humidity (moisture)
Selecting the correct air conditioner for your home is an important consideration. A properly installed and functioning air conditioner is critical to your comfort and wellbeing. While every home is different, there are a number of things that you can do to ensure that you are getting the best service and the right air conditioner for your needs.
Don’t hire a contractor who wants to size your unit based solely on the floor area of your house. Contractors should calculate how much cooling a home needs according to the guidelines set forth in the Manual J of the Air Conditioner Contractors of America (ACCA). Studies show that one third to one half of home air conditioners don’t work the way they should because they are oversized. Contractors generally size air conditioners at least a half ton larger than necessary, and often oversize by a ton or more. (We’re not talking about the weight of the air conditioner here, but tons of cooling. One ton of cooling is approximately how much cooling you’d get from melting a ton of ice. One ton of cooling is equivalent to about 12,000 Btu of air conditioner capacity.)
Insist on getting a copy or computer printout of the cooling load calculations. Ask your contractor to size the air conditioner based on the latent cooling load (which considers the humidity of the air) as well as the sensible cooling load (which considers the temperature of the air) for your home. Don’t be tempted by the lowest bid. Be willing to pay for the time the contractor must spend to do the job right.
Buy a high-efficiency unit. New air conditioners are required by federal law to have a SEER of 13 or higher. Even though it will cost more, it’s usually worth it to buy a higher efficiency unit, because that initial investment will be paid back with energy savings over time. Look for an ENERGY STAR label when you shop. If you are replacing an existing air conditioner, you must replace the whole unit, including the inside coil and often the blower fan, to achieve the rated efficiency.
Install for ease of maintenance. Make sure the inside coil can be reached for cleaning. The contractor may have to install an access panel, depending on the model. The coil should be cleaned every two years. The air filter should be located where it is easy to remove. Check it every month during the summer, and clean it or change it whenever it is dirty.
Place the outside unit on the north or east side of the house, out of direct sunlight, but don’t add shade for it. Leave plenty of room for free airflow on all sides, and leave at least 4 feet of clearance at the top. Keep the area free of debris and shrubbery. The air conditioner draws a lot of air through it. It’s more important for the unit to have a lot of space than for it to be well shaded.
Another important consideration is the ability of the selected air conditioner to remove moisture from the air. Different models have different abilities to handle moisture. The contractor should understand how to pick an air conditioner that is suitable for your house, and for your climate.