Air Filter Basics for Home and Auto

Does it help against COVID-19 to keep a clean heating and air filter? Yes! It does. However, air filters, and including heating and air conditioning filters are not 100 percent. Yet, without keeping clean air filters, the risk for spreading COVID-19 within a household is increased. In fact the CDC says, “When used properly, air cleaners and HVAC filters can help reduce airborne contaminants including viruses in a building or small space. By itself, air cleaning or filtration is not enough to protect people from exposure to the virus that causes COVID-19. When used along with other best practices recommended by CDC and others, filtration can be part of a plan to reduce the potential for airborne transmission of COVID-19 indoors.” (Air Cleaners, HVAC Filters, and Coronavirus (COVID-19))

There are several rating systems out there for selecting the right air filter for your HVAC unit. The Minimum Efficiency Reporting Value (MERV), Filter Performance Rating (FPR), and the Microparticle Performance Rating (MPR) are three of the most common. All ratings are understood like the one-to-ten scaling system. The lowest rating means the filter does not remove as much as the highest rating. So, the most effective filter would remove particles such as;

  • Dust/Lint
  • Airborne Dust/Mite debris (Mite feces)
  • Pollen
  • Ped Dander
  • Mold Spores
  • Bacteria
  • Microscopic Allergens
  • Virus Carriers
  • Odor
  • Most Smoke
  • Smog Particles

The least effective rating would only remove;

  • Dust/Lint
  • Airborne Dust Mite Debris (Mite feces)
  • Pollen
  • Pet Dander

The CDC (The Center for Disease Control) says the any filter that is rated by the MERV system, and is rated 13 or above will remove at least 50% of the smallest particles tested. This does not mean that you have to buy a filter rated by using the MERV system. The filter should clearly list that it can capture bacteria, virus carriers, and microscopic allergens within the filter’s long list of particle captures.

The filter in your home should be replaced every 60 to 90 days. When replacing the air filter, wear a mask to prevent the inhalation of particles. The filter compartment area should be well dusted. Usually by vacuuming the entire area, and making sure that the compartment vent cover is also dust free.

Sometimes, the filter compartment can be caked with thick dust that won’t remove easily with a vacuum. If this is the case, spray the entire area with a disinfectant like Lysol (How to Clean an Air Conditioner). Wipe the saturated surface clean. If dust is found stuck between the coils, use a cleaning brush to dislodge the clumping. Once the coils, all areas around the coils, and the cover are cleaned and disinfected, spray the new filter with Lysol spray.

Be sure to inspect your filter compartment. Look for mold that could be hiding in the coils and surrounding areas. Be careful. The mold could be black, white or even orange. If mold is found, do not clean with Lysol. Clean with a solution of water and bleach instead. You should use 1/2 cup of bleach to a gallon of water. Scrub the compartment as you would with Lysol. This will remove the mold and kill any remaining spores.

As far as the automobile goes. It is a good idea to change the cabin filters of your vehicle. There has not been any research as to the effectiveness of auto cabin filters against the spread of COVID-19. Yet, it could be an area to practice the ‘better safe than sorry‘ technique.

According to AAA, “New cars are increasingly equipped with cabin air filters that remove particulates, and sometimes odors, from the air that enters the vehicle through the heating, ventilation and air conditioning (HVAC) system. Cabin air filters are usually standard equipment on premium models, while other cars make them available as a stand-alone option or part of an option package. Some luxury cars have two or more cabin air filters.” (Changing the Cabin Filter in Your Car.)

The general list as to what a car’s cabin filter captures varies much like your homes air filter varies. In general, however, a car cabin filter’s capture rating usually consists of;

  • Dirt
  • Dust
  • Leaves
  • Twigs
  • Insects
  • Soot
  • Smog
  • Mildew
  • Pollen
  • Mold spores
  • Fungi
  • Bacteria
  • Germs
  • Rodent droppings
  • Other various particles

How often to change the cabin filter/filters in your automobile varies from every 15,000 to 30,000 miles. This depends on several factors. Factors like weather or not you live on a dirt road where dust is too often.

It is possible to change your cabin air filter yourself. Your decision to do so may depend on the location of your automobiles cabin air filter. Some cabin air filters are located behind the glove box, and easy to get to. Others require a greater amount of removal of the dashboard. This could be done at home or you may opt to have it done professionally. If you are interested in doing it yourself, this video by AutoZone may help you get it done yourself. Breathe better!