Air filters are an essential component of forced air HVAC systems, as they help to clean the air and protect the HVAC engine, while also improving indoor air quality. Filters should be installed on the return side of the HVAC air handler, as well as in any fresh air intakes to clean outside air entering the home. It's important to note that filters with MERV (Minimum Efficiency Reporting Value) ratings higher than MERV 6 or higher can trap contaminants such as pollen, dust mites, and mold spores. However, a dirty, clogged filter can dramatically reduce airflow, increasing oven runtime and increasing both engine wear and energy consumption. For optimal operation of both the filter and the HVAC equipment, filters should be replaced or cleaned frequently.
Therefore, the filters should be located in a location that is easily accessible to the homeowner. When installing an air filter, it's important to pay attention to the arrows printed on the sides of the filter. These arrows should point in the direction in which the air flows through the system, which is away from the supply ducts and (normally) to the blower. If the filter is on the wall, the arrow should face the wall. If there is no arrow present, then you'll want the side with the wire frame to face outward. It's also important to note that these requirements only apply when the filter is installed in a media box located in the HVAC system, not when the filter is installed flush with the return grid.
Professionally installed air filtration ensures that the filters are the right size to ensure adequate airflow for a home's heating and cooling air controller and that all filter grilles are airtight. In addition to this, Standard 680 sets forth definitions, classifications, test requirements, data requirements, ratings, operational requirements, marking and nameplate data, and compliance conditions for residential air cleaner equipment. If your home is equipped with a fresh air inlet that is channeled to the air handler, a filter should be installed at this fresh air inlet and it should be located where it is easily accessible so that it can be replaced or cleaned as needed. Standard 52.2 establishes a laboratory testing method for measuring the performance of general ventilation air cleaning devices in removing particles of specific diameters. With these ratings, you can expect your filter to remove large particles, small particles, smog, smoke, allergens, and odors. In homes with ducted HVAC equipment, it's important that HVAC contractors specify and install furnace filters in both the return chamber of the air handler and on all return grilles. Additionally, any outdoor air intake should also have a filter installed.
It's also important that these filters meet all design pressure drop specifications on their return grid labels. Finally, if your oven is located in your attic then it's important that your attic is equipped with a folding ladder or ladders and a permanently installed walkway so that you or a service technician can reach your oven easily. However, filter replacement may vary by system so be sure to refer to your specific unit's instructions for more information.