Defeat the heat: Maintain unit to chill out

The heat this summer is unbearable. What can I do to make sure my air conditioning unit is working properly?–Dazed and Confused

A: Since air conditioning units are often neglected, the air filters in front of the equipment can capture big particles of dust and dirt that will block up the coil. As a result, the unit overheats, which is dangerous and causes your energy bill to go up. The system won't cool as well, and it will run longer than normal.

The solution is regular maintenance. You should call in a professional once every six months. He'll make sure the filter's unclogged, there's no debris in or around the system, the thermostat's working, and the drain line isn't stopped up. One visit will typically cost about $80, but often there are deals and discounts for preferred customers.

The occasional visit from a professional does not mean a homeowner can ignore the system the other 363 days of the year. The filter needs to be changed every 30 days. A dirty filter can increase energy bills $20-$30 a month.

If you have an outdoor unit, it should be kept free of debris. Trim any surrounding shrubbery, keeping at least two feet of clearance around the unit and a minimum of six feet above. Additionally, the unit should be at least four inches off the ground, on a pad and supported by feet.

People have major misconceptions when it comes to operating air systems. A lot of people will keep the thermostat at 72, change it to 80 when they're at work, and then come home and turn it back to 72. But it's actually cheaper to leave it at a comfort level even when you're gone. If you're interested in saving money, the best thing to do is to keep the temperature a degree or two higher than your normal comfort temperature all the time.

It's a bad idea to use ventilators if you're using an air conditioner. They allow hot air to come inside. You should also avoid using exhaust fans for a long period of time, since they will suck the cool air out.

The best thing a homeowner can do when it comes to air conditioners is to perform regular visual inspections. Check the condensate pan, which lies underneath the unit, to make sure it contains no water. If it does, you can either attempt to clean the drain yourself, using a shop vac, or call a professional. In such a situation, the drain line is clogged, and that can potentially cause water damage.

Also check your thermostat to make sure it's functioning properly. If it's mercury, see that it's mounted to the wall correctly, or it may read wrong. Be sure to have it calibrated when the air conditioning unit is serviced.

If you're concerned about the costs of air system maintenance, keep in mind that a recent study done in North Carolina showed that it was more cost-effective to properly maintain the units than to allow them to clog and hike up your energy bills. Responsible maintenance is less expensive and far more comfortable.

Tom Kavounas of Albemarle Heating & Air