The same air is cycled through a house and unit over-and-over cooling or heating the air.
During the air cycle, it passes through what is called the condenser and evaporator coil.
Both the condenser and the evaporator are much like a car radiator that air must pass through to blow out hot air or blow in cool air.
The condenser blows the hot air away from a unit while the evaporator cools the air as it passes through and blows air into a home through the vents.
When Return air filter gets dirty or the evaporator coils become clogged no air can pass through the unit which will often cause it to form ice letting even less air through and stopping the unit from working correctly.
What is an HVAC Return Filter For?
A Return air filter is essential to keeping an HVAC unit working properly.
Changing out the filter should be done routinely. It will depend on the area as to how often, for example, desert locations because all the dust sometimes require the filter to be changed weekly, most often though once a month is standard.
How to Replace a Return Air Filter
Changing a Return air filter is simple enough, it is most often a large grill that is located on the ceiling or a wall.
A hallway is the usual location but it may be located somewhere else. A ladder will often be needed to reach it and unlatch the door that will expose the filter.
How to Buy a Return Air Filter
The dimensions of the filter will be needed to buy another one. The size of the filter is measured by inches, in width and length.
For example, a 24X16 Return air filter is 24 inches long by 16 inches wide.
Almost all filters will have the dimensions clearly labeled.
A Return Air filter can be bought at local hardware stores or online with Amazon and eBay.
Example Return Air Filter on Amazon
FilterBuy 20x20x1, Pleated HVAC AC Furnace Air Filter, MERV 8, AFB Silver, 4-Pack