Central air conditioning systems are equipped with filters to ensure good air quality as the unit circulates between indoor and outdoor air. Usually, a house will have two air filters on its intake grilles, but this number may vary depending on the size of the house and the number of floors the central air system must support. The general rule is one filter for each air controller. Most homes, especially large ones with multiple HVAC systems, have more than one air cleaner installed.
Commonly used in HVAC — R, these orange polyester antimicrobial rolls provide a more durable solution that can be used to replace filters over time and excellent mold prevention. However, if you have pleated air filters, you won't have to change them for at least three months and sometimes up to six months if they are of high quality. It is important to locate all of the air filters in your home. All central heating and cooling systems must have an air filter, but it may be more difficult to locate it in some HVAC units than in others.
You should check every possible location to ensure that you have found all your air filters. Usually, a house will have two air filters in its intake holes. In some cases, there may be more or less depending on the square footage of the house or apartment and the number of floors the central air system must support. The air filter is usually found in the return air duct or in the fan compartment before the return air reaches the air controller.
The air controller is a large metal box; you should look for something that looks like a removable cover (i.e., the filter slot). It is easy to identify the return air outlet when the heat pump is turned on, it is enough to place a piece of toilet paper near the ventilation grille so that the return air absorbs the tissue. If you think that a single 1-inch filter isn't doing a good job of filtering particles out of the air, then opt for a thicker option, if the filter slot allows it. Once you have located all of your home's air filters, document their location for future building owners, occupants, or repairers.