You may remember hearing a technician or family member say, “Oh, I guess it’s time to change that filter” and watching them remove a fuzzy gray rectangle from behind a dusty grate in the wall.

That fuzzy gray rectangle was the air filter, one of the most important factors in maintaining a comfortable, safe breathing environment in your home.

These filters (also known as mechanical air filters) serve your home in two ways. First, they clean the air in your home. This protects your health and reduces dust inside. Second, they protect your air conditioning system from clogging up and overworking.

The type of filter you choose and the frequency you replace it improves the success of your air conditioning system and your indoor air quality.

Consider these tips as you choose your air filter.

How a Mechanical Air Filter Works

Mechanical air filters act as a blocking device to air as it travels through the air system. Air has to flow through the filter, and so does any mold, dust, smoke, pollen, or bacteria in the air.

To put it simply, filters trap pollutants and stop them from returning to the circulating air flow in your home.

Varieties to Choose From

Before you select a filter, compare the quality of filters available. Don’t just rely on price differences. While saving money is important, so is ensuring good air quality and health.

First, look up the dimensions so you know what size of filter to buy. If you have trouble locating the right dimensions, a heating and cooling technician can help you.

Next, compare the following types of filters:

·        Fiberglass air filters: These filters are thin with a flat surface. If you want to save money and don’t mind a few particles in your air, fiberglass panels are a good option.

·        Pleated air filters: These filters are fairly inexpensive and have a medium to high efficiency rating in how much they filter out of your air. This air filter type is a common and useful option for most homes. The pleats give the filters more room to trap up to 45% of pollutants while maintaining optimal airflow.

·        High-efficiency air filters: These come in pleated and polyester varieties that sometimes have a chemical coating to kill bacteria and mold. Some of these filters can remove 85% of your air pollutants, keeping your air clean and easy to breathe. This is a great option if you are extra sensitive to allergens or have respiratory problems.

·        True high-efficiency particulate air filters (HEPA): These HEPA filters are so efficient that you can only use them in a standalone air purifier or in a whole house filtration system with a special HEPA filtration system included. These filters block too much airflow from normal home air conditioning systems, because typical systems do not have enough pressure to blow air through these filters and back into your home. But if your home supports this type of filter, you could enjoy up to 98% pollutant filtration.

Mind the MERV

The MERV rating determines how efficient your filter is. All mechanical filters have a MERV rating from 1 (poor efficiency) to 16 (high efficiency). Fiberglass filters, for example, are thin and have a MERV rating of 1 to 4. Pleated filters have a MERV rating of 10 to 13, and high-efficiency filters have a rating of 14 to 16.

This rating is a great way to see how much your filter can block from the air. Just keep in mind that you want enough unrestricted airflow so your unit does not overwork.

Change Your Filters Often

If you leave your clogged and dirty filter too long, your filter will also begin to restrict airflow. When your air unit works too hard to push the air through, the strain can damage your air conditioning system.

Change your mechanical air filter every two to three months, if not more frequently, to increase the efficiency of your air system.

Watch for signs of dust accumulating, especially on the grate where you keep your filter; this may mean it’s time for a new filter. If you continue to notice efficiency problems in your air conditioning (even after a filter change) contact your local heating and cooling company for help.