There’s no “one-size-fits-all” answer to this question. The truth of the matter is, there is so much that affects the level of indoor contaminants that come into your home. And your indoor air filtration is the most effective way to remove them from the air before it is circulated through your home.
Some of the ways contaminants get into your air:
- Whatever is happening outside your home. Construction, air pollution, paint, dust, and any other dirt that is passing by your home can be let in through doors and windows.
- The people who pass through or live in your home. People and pets release bacteria, virus particles, dander, and other contaminants into the air inside your home.
- Activities and materials in your home. If you’re using diffusers, cooking with oil, doing minor repairs—all of these activities release contaminants that can remain in your air if they aren’t removed through proper filtration.
Your furnace’s main function is to bring outdoor air into your home, “clean” it via filtration, circulate it throughout your home via your HVAC system, and either exhaust it outside or re-clean and recirculate it.
If your filter isn’t catching all of the contaminants, then you’re breathing in air with harmful particles in it.
As of 2020, with the additional research being done throughout COVID-19, ASHRAE has released guidance that even homes should have a minimum of MERV 13 air filters in their furnaces. Read more from ASHRAE here.
For some homes with older equipment (at least 10-15 years old), MERV 13 filters might make your furnace work a bit too hard for what it can handle, but for most modern systems, this should help keep you indoor air free from harmful particles.
Don’t just take our word for it. Take Tylor’s.
Almost 4 months on the MERV 13, oh my goodness. Insane amounts of particles were stopped. Never saw this before out of the MERV 11's I used to buy, not even CLOSE.This is fantastic! A week ago the furnace actually came on since it was only 8 degrees and wet out. I noticed no dust came out when the air was blasted into the house, which used to be an issue with other brands of filters. The furnace came on, with the filter as dirty as you see it here. Dust from the area (new development) and wildfire smoke and ash!
- Tylor, Edmonton