Installing an air filter correctly is essential for ensuring that your home is free from harmful particles such as pollen, dust mites, mold spores, pet dander, tobacco smoke and other contaminants. To ensure that your air filter fits perfectly, it is important to measure the length and width of the filter slot before purchasing a new filter. Most air filters have their size printed on the side of the frame and should be slightly smaller than the measured outer length and width of the frame around the opening. When installing an air filter, it is important to make sure that the arrows printed on the sides are pointing in the direction in which air flows through the system, which is away from the supply ducts and (usually) towards the blower.
If a filter does not fit perfectly, unfiltered air will pass through the path of least resistance, and the filter will be partially, if not completely useless. The MERV rating of an air filter is a measure of how effective an air filter is at removing particulates from the air. A combination of a thin air filter with a high MERV rating can also restrict airflow to the point of impairing efficiency and causing excessive wear and tear. Therefore, it is important to choose an air filter with a MERV rating that is appropriate for your home.
Most white pleated air filters are inherently the same within each efficiency level, varying slightly, if at all, between brands. Filters should be changed every 30 to 90 days, depending on filter type and efficiency. At the same time, a coarser filter is less restrictive and will allow better flow of purified air.HVAC service companies typically offer air filter replacement services in addition to system repair and unit installation services. As a central heating and cooling system owner, one of your most important maintenance responsibilities is to change your air filter regularly.