September 3, 2022

An air filter is a device that filters particles from the air. Changing and maintaining your HVAC air filter/s is essential to keep your HVAC unit - and yourself - healthy. In this blog, we will cover the most common questions we get about air filters and their vital role in your and your HVAC unit's health.

AC filters are mostly made out of a fine fiberglass thread which is then spun on a frame or made from fine paper or cloth wrapped on a cardboard frame. Some particles which an air conditioner filter can help protect you against include:

  • Pollen
  • Mold
  • Pollutants present in the outdoor air
  • Dust
  • Fur from pets
  • Dead skin or dander

The cleanliness of AC air filters is essential for people who are sensitive to air quality and have allergies or respiratory conditions such as asthma. Overall, air filters can be beneficial for everyone by improving your indoor air quality, considering you make sure your air filter is not dirty!

How Do Air Filters Help or Harm my HVAC Unit?

HVAC systems are key to your home's comfort level, however, your HVAC system should be well maintained to ensure its maximum efficiency. One of the most important — yet sometimes confusing — parts of an HVAC system is the air filter. Air filters not only improve indoor air quality, but they ensure all of the dust, dirt, dander, and pollen never reach your HVAC unit. If those particles and pollutants reached your evaporator coil it could prevent air from flowing through the coil, causing it to ice up and block air from flowing through the vents into your home. Similarly, if your filter has a MERV rating that is too high, it could prevent the return from pulling in an adequate amount of air, which would also cause the unit to ice up and create unnecessary wear and tear on the compressor.

How Often Should I Change My HVAC Air Filter?

AC Filters should be changed often, but how often depends on many factors:

  • Air filter design
  • Overall indoor air quality
  • Quantity of pets
  • Household size
  • Air pollution levels and construction near the residence
  • The MERV Rating

Most residential air filters should be changed every 60-90 days. However, if there are several pets in the home, new construction near the residence, or you have a larger household size, you may need to change your filter as often as every 14-30 days. As a general rule of thumb, filters should be checked every 2-4 weeks, if the filter has turned mostly gray, it is time to change it, if not, you can recheck it in 2-4 weeks.

What is a MERV Rating?

MERV ratings measure the filter's ability to capture particles between 0.3 and 10 microns (µm). A MERV (Minimum Efficiency Reporting Value) rating is derived from a test method developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) The higher the MERV rating, the more particles the filter can remove from the air.

What MERV Rating Should I Buy?

Using a filter with a MERV rating that is too high can actually do more harm than good to your unit! In most residential settings, a MERV rating of 6-8 is best. A MERV between 6-8 allows for maximum removal of larger particles and pollutants without compromising the health of your unit. If you or your family is prone to allergies or other respiratory conditions, an air scrubber can provide an even healthier and more efficient home. Air scrubbers can kill particulates like dander and pollen, volatile organic compounds (VOCs) that create odors like smoke, and organisms like mold and viruses.

Additional Air Filter Tips:

  • Most air filters are located in the return vent which is usually in the wall and typically below the thermostat.
  • Pay attention to the arrow on the filter and ensure the arrow points towards the ductwork when installing your filter into the return vent.
  • Your home may have more than one air filter, especially if it has more than one level.
  • Don't forget to check filters on Mini Splits and PTAC units (wall units). These filters are typically reusable and should be rinsed off in the sink, dried, and re-installed.

For more information on air filters, HVAC maintenance, and/or air scrubbers call your local service professionals at Honest Air Heating & Cooling, LLC today at 615-517-2045 !