Old, dirty air filters can cause your heating and cooling system to operate incorrectly and may result in possible system damage and/or replacement. Air filter maintenance can also help improve indoor air quality (IAQ) in your home, which is important to good health. So, cleaning/replacing your system’s air filter is helpful in maintaining both your HVAC system and family’s well-being.
Fortunately, simple or do-it-yourself HVAC maintenance doesn’t get any easier than air filter maintenance. In addition to cleaning or replacing air filters regularly, you can also test if your air filter is efficient at removing pollutants, allergens and other particles from your home. Position your current air filter horizontally, then pour common table salt onto the filter. Note how much of the salt passes through the filter. If more than a few stray granules come out the other side, your filter is probably not very efficient at slowing down dust particles or pollutants of similar size. So, it might be a good idea to replace the filter and upgrade to a more efficient type.
So, what types of filters are best at enhancing IAQ? The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) employs a rating system that determines the minimum efficiency reporting value (MERV). MERV ratings range on a scale from 1-20, and are based on two key criteria: how efficient the air filter is at removing particles and resisting airflow and how long the filter should last.
Here are the three main types of air filters and their MERV ratings:
- Flat-panel fiberglass. These filters are the most common and are composed of layers of fiberglass fibers. They are disposable and come with a rating of 1 to 4. While inexpensive, these filters have a lower rating for capturing smaller dust, dander and bacteria particles.
- Pleated polyester. These filters are rated from 5 to 13 and are generally several times more expensive than fiberglass. However, the pleats create more filter surface area to capture smaller air particles and pollutants.
- High-efficiency particulate air (HEPA). HEPA filters have a rating of 17 to 20 and are recognized by the Occupational Safety and Health Administration as the top filter for removing air particles and pollutants. Their size is problematic, though, as most residential heating and cooling systems are not equipped to accommodate HEPA filters. Retrofitting your furnace to fit HEPA filters will require the services of an HVAC professional.
In the meantime, replace your old filter regularly. Determine the proper size, remove the current filter from the furnace compartment or lost and properly dispose of it. Taking note of the airflow direction, install the new filter. For more information about air filter efficiency and maintenance or for a fall tune-up, call The General today.