Summer's steamiest days can keep even the most intrepid among us shuttered indoors seeking the sublime relief of air conditioning. And with temperatures predicted to be above average for much of the country, you'll want to make sure your A/C is in good working order, Consumer Reports says.

Once upon a time, window air conditioners were the norm, but today about 90 percent of newly built homes come with central air. If you already have it, bear in mind that systems tend to last no more than 15 years, and if yours is at least 10 years old, it probably no longer meets today's energy efficiency standards. Upgrading to a new system could cut your cooling costs by 20 to 30 percent.


Central air's appeal is pretty obvious; the seasonal ritual of installing and uninstalling window units every summer and fall can be tiresome and difficult. But switching to central air can be disruptive and expensive. To assess whether it's a good investment, consider two factors: the length of the cooling season where you live, and whether most nearby homes have central air. If you live far south or west in the country, home buyers probably expect it, so if you don't have central air, it could lower your home's value. In the Northeast, it isn't as critical because the cooling season is shorter, and many older homes don't have it.

The messiest part of installing central air in an older home without a forced-air heating system is creating the duct system. Another option is a split ductless system. It cools more uniformly, like central air, but instead of using ductwork, the systems have multiple indoor units (called air handlers) mounted high on the wall, as well as an outside condenser. The mechanicals between the two parts are carried by thin tubing through a small hole in the wall behind each unit. You'll need one air handler for each room, and you can turn them on all at once or just cool the rooms you're using. Professional installation is recommended.


The ABCs of central A/C: Wherever you live, if you are putting in a central air system, you'll want to pay attention to energy efficiency. For the first time, the federal standards differ by region, with central air conditioning systems in the hotter South and Southwest required to meet stricter standards than those installed in the cooler North. A system's yellow Energy Guide label now includes a US map of the that shows where the equipment can be installed. More efficient setups might cost more, but you'll save on utility costs over the life of the system. But to get that savings you'll need to replace the exterior unit, or compressor, and the interior unit, or air handler, and make sure your ductwork is insulated.

Expert tip: If your furnace is more than 15 years old, Consumer Reports suggests that you consider replacing both the furnace and air conditioner because a new A/C system won't work as efficiently if it's connected to the blower motor of an old furnace.

Assuming you've decided to take the plunge, you'll want to choose a dependable central air conditioning system. There are two types: conventional, which are more common in areas with wide temperature swings, and heat pump, which are usually used in areas with more moderate cooling and heating needs. Heat-pump systems, used for cooling and heating, move warm air from your cool house outside when it's hot out and do the opposite when it's cold.