How to Choose Air Conditioner Filters

Danny Lipford shows the selection of air conditioner filters available for purchase
A quality pleated air conditioner filter, pictured at the left, will catch more particles than a cheap grocery store filter, pictured at the right.

How well your central heating and cooling system cleans the air largely depends on the quality of your air conditioner filters.

Filters are rated from 1 to 16 on the Minimum Efficiency Reporting Value scale. The MERV scale is based on the percentage of particles, from 0.3 to 10 microns in size, that the filter catches. The higher the MERV number, the better it filters the air.

The Microparticle Performance Rating measures very small particles between 0.3 and 1 microns. Ratings on the MPR scale range from 0-2200. The higher the number, the smaller the particles that a filter removes.

Mold spores and pollen are usually in the 10-30 micron range; bacteria, 2-3 micron; and tobacco smoke, 0.5 micron.

Understanding the MERV Scale

Here are some guidelines to consider when choosing air conditioner filters:

  • MERV 1-4 Air Filters: These inexpensive fiberglass mesh filters only remove particles over 10 microns in size. They do little to improve the indoor air quality in your home.
  • 5-8 Air Filters: These medium-quality pleated air filters can remove particles down to 3.0 microns in size.
  • 9-12 Air Filters: These high-quality air filters can remove particles down to 1.0 microns in size.
  • 13-16 Air Filters: These are the highest-quality, standard filters. They can remove particles down to 0.3 microns.
  • 17-20 Air Filters: These filters, also known as HEPA (High Energy Particulate Air) air filters surpass the standard MERV rating by removing 99.97% of airborne particles 0.3 micron and larger. While often used in hospitals, they cause too much air resistance to be installed in a standard HVAC system without making modifications.

Other Ways to Reduce Allergens

In addition to choosing quality air conditioner filters and changing them regularly, you can do other things to help clear the air in your home. 

Here are some examples: 

  • Limit or remove carpets and rugs.
  • Keep pets outdoors.
  • Reduce Volatile Organic Compounds in your home.
  • Use a quality vacuum cleaner equipped with a HEPA filter.
  • Install a room air purifier equipped with a HEPA filter.

Further, certain houseplants can improve air quality. These include philodendron, peace lily, dracaena and snake plant.



Keep Your Cool with Today's Homeowner!It’s Keep Your Cool Week, sponsored by American Standard HVAC! Give your air conditioner some TLC — click for all the money-saving advice you need to stay cool and comfortable this summer.

More on Air Conditioner Filters and Indoor Air Quality

Previous article5 Tips to Keep Your Wood Deck Looking Its Best
Next articleAir Conditioner Guide: From Maintenance to Buying New Systems
DANNY LIPFORD

Backed by his 40-year remodeling career, Danny served as the home improvement expert for CBS’s The Early Show and The Weather Channel for more than a decade. His extensive hands-on experience and understanding of the industry make him the go-to source for all things having to do with the home – from advice on simple repairs, to complete remodels, to helping homeowners prepare their homes for extreme weather and seasons.

Related posts