Changing The Filter


One of the most common questions we get asked is how often should furnace filters be changed. Changing your furnace filters is the easiest things you can do to keep your heating and cooling system running in tip top order. This simple act keeps your system running efficiently, avoids system breakdowns and can lengthen the lifespan of your system. For this reason, it is extremely important you change your filters on time. So how often do we need to change our filters?

Filter Type

Filter types are determined by their MERV Rating. A MERV Rating, Minimum Efficiency Reporting Value, measures the effectiveness of filtration. The higher the MERV Rating the more effective the filter is at not allowing air particulates to pass through it. The MERV rating also determines generally how often to change your furnace filter. MERV 8 filters should be changed every 3-4 months, MERV 10 & 11 filters every 6 months and MERV 16 filters every year.

Household Factors

There are certain household factors that could change how often to change the furnace filter. First, do you have an air purifier? If so, you will end up needing to replace your furnace filters more often. Air purifiers improve the Indoor Air Quality (IAQ) in your home because they clump the air particulates together so they get stuck in your furnace filter and aren’t circulated throughout your home.

Other factors in needing to change your filter:

  • Animals in the home
  • Lots of dust in the home
  • Keeping the heating and/or AC fan on
  • Smoking in the home
  • Keeping the windows open
  • Individuals who suffer from allergies or asthma
  • Young children in the home

Visual Check

If you are still unsure about your furnace filter change frequency, you can complete a visual check. If there is only a thin layer of dirt where you can still see the filter underneath it, then you probably don’t have to change the filter. However, if there is a thick layer of dirt on where you can’t see the filter underneath it then it’s time to change it out. We recommend doing a quick visual check on your filter every 3-4 weeks if you are unsure about your furnace filter replacement frequency.