HEPA Filter in Furnace

Your furnace filter collects dust, debris, allergens, dander and even hair as it flows through your furnace. This significantly improves your air quality—unless your filter is so full that it can’t do its job. Then you need to replace your furnace filter. However, don’t think you’re stuck buying the same filter that is already in your furnace. You can get furnace filters of varying quality to help keep your furnace running well and clear your home of impurities.

Furnace Filter Size

You do have to choose the right furnace filter size. To find out what yours is, just take a look at the existing filter inside your furnace. In our experience, the most popular sizes are:

  • 16x25x4 furnace filter
  • 16x25x5 furnace filter
  • 20x25x5 furnace filter

The three numbers refer to the height, length and width of the filter. While you have no choice about the size, you can get filters of different quality.

High-Efficiency Particulate Air (HEPA) Filters

Most homeowners know that HEPA is a top of the line system for removing impurities from the air. It makes sense that you’d want such a quality filter for your furnace at home. However, such an impressive filter would restrict the furnace’s airflow too much and could end up causing problems. HEPA filters are not considered necessary for furnaces, but the very best filters on the MERV scale come close to HEPA quality.

Dirty Filter

What’s the MERV Scale?

The MERV scale describes the quality of furnace filters based on what they can filter out of the air. The higher the rating on the MERV scale, the better the furnace filter. Those filters at the 13-16 range on the MERV scale are the closest you can get to HEPA quality. Here’s a quick break down of the MERV scale:

  • MERV 1-4: These filters are the bare minimum, removing pollen and dust (including sanding dust).
  • MERV 5-8: A slight improvement, these filters will also catch mould spores and dusting aids (sprays that make dusting easier).
  • MERV 9-12: These quality filters will catch everything listed above, plus some large bacteria such as legionella. They will also catch humidifier dust and auto emissions.
  • MERV 13-14: The highest quality filters available, these catch everything listed above plus all other bacteria types, most tobacco smoke, and sneeze droplets.

The best MERV furnace filters remove things in the air that are 1 micron and larger. That is very small but consider that HEPA filters remove things 0.3 microns and smaller. This allows them to catch viruses and other contaminants that your furnace will miss.

What Type of Furnace Filter do I Need?

Not sure which filter you should buy? Or, thinking of getting a HEPA filter to improve your home’s air quality even more? Contact Link ClimateCare for all of your HVAC needs.

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