Keeping your home air conditioning system in top condition is essential for a comfortable living environment. To ensure your AC unit is running efficiently and effectively, it's important to clean or replace the filter or filters every one to two months during the cooling season. Filters may need more frequent care if the air conditioner is used constantly, is exposed to dusty conditions, or if you have furry pets in the house. Look for the minimum filter efficiency value, or MERV, which ranges from 1 to 12 for domestic air conditioning units; the higher the number, the better the filtration (and the more energy it will take to extract air through the filter, so balance air quality issues with energy costs).Ducts can lose up to 30 percent of airflow due to leaks, and window air conditioning units are notoriously difficult to seal properly.
To detect any leaks, you can use the old “smoke trick”. The air compressor and condenser in a central air conditioning system are usually outside the house, close to the foundation. It works best when there's around 24 inches of free space in all directions, so get rid of nearby shrubs, tall grass, leaves, and hanging branches. Federal laws require air conditioning units to be much more efficient than they were just 10 years ago. For central air conditioning, look for the seasonal energy efficiency index, or SEER; for window units, the measurement is simply called the energy efficiency index, or EER.
The standards require a SEER of 13 and an EER of 8, but devices with higher numbers will cost less to operate. Often, the pipe drains to the outside, near the condensing unit, but it can also flow into a utility sink or basement drain or, in the case of attic units, into an outside wall. The cold coil absorbs heat from the air and cools it before the air circulates back to your home. Unless you're going on vacation, don't turn off the system; otherwise, the air compressor will have to work harder to cool the house later on. If every homeowner strives to maintain and repair their home regularly, then you can save a lot on costly maintenance expenses. For example, a slow refrigerant leak in your AC unit can cause expensive compressor failures; however, homeowners don't have the tools or skills needed to check refrigerant levels.
The dealer that installed your central air conditioning system (or one you find in your area) should set up an annual cleaning program that goes beyond simply cleaning the filters. While these steps will help you keep your air conditioning system in perfect condition, keep in mind that there are maintenance tasks that only a trained HVAC technician can perform. We asked Richard Trethewey, plumbing and heating expert at This Old House, to share his tips on air conditioning maintenance for central air units and windows. During winter months when your condenser is not in use, it is good practice to cover its top with a piece of plywood or plastic to prevent debris from falling. Closing too many interior doors causes central air conditioning systems to become unbalanced; this means there is less airflow throughout your house. Consider running your AC unit along with floor or ceiling fans to help cool air circulate more effectively.
For window units, turn on an incense bar and hold it where the unit and window frame meet; for central AC systems hold it close to duct connections.
