The air filter for your forced-air heating or cooling system is crucial to the proper operation of that system. Choosing the right filter for your equipment is essential to both its performance and energy efficiency. Choosing the wrong filter can result in issues with airflow, air quality, and heating and cooling delivery. A key part of your decision-making process should therefore be the energy efficiency rating of an air filter, usually measured by the MERV system. If you go to the home improvement or hardware store looking for a filter, however, don’t be surprised if the packaging gives you some other efficiency rating rather than MERV.
Understanding MERV
MERV is short for Minimum Efficiency Reporting Value, an industry standard measuring how well an HVAC filter removes the smallest particles from indoor air. In the MERV system, which runs from 1-16 for residential air filters, the lowest numbers only capture the largest particles. This system gives consumers a good basis to compare air filter technology. Following is a rough guide to how the ratings break down:
- MERV 1-4: will do a basic job of removing heavy dust particles, pollen and fibers from indoor air, but won’t do much for indoor air quality.
- MERV 5-8: will remove finer material such as spores and pet dander.
- MERV 9-12: will remove a wider range of particulates, including some bacteria, viruses and mold spores. Like some filters in the 5-8 range, these are often pleated filters with more surface area for capturing particulates.
- MERV 13-16: removes bacteria and exhaled particles (operating theater air level cleanliness). At this efficiency level, the filter’s thick design will start impeding system airflow, plus it may need serious system modifications to work with your equipment.
- MERV 17-20: HEPA filtration, not recommended for most residential systems unless under certain conditions.
You should be able to find the air filter MERV rating on the information label of the air filter, but it doesn’t always appear there.
Help! Where’s the MERV?
Sometimes manufacturers and retailers have their own rating labels independent of the MERV rating. This can be confusing if you are looking for equipment to meet a specific MERV rating, as the numbering systems usually do not match. Make sure you get the sales people to qualify what the different rating levels equate to precisely against a MERV rating.
Expert Advice
For friendly no-obligation advice on air filters, MERV ratings, or any other matter related to home heating and cooling, please contact us at Energy 1 Heating & Air Conditioning. For 35 years, we have been looking after the home comfort needs of people in Lorain and surrounding communities.
Our goal is to help educate our customers in Lorain, Ohio about energy and home comfort issues (specific to HVAC systems). For more information about air filters and other HVAC topics, download our free Home Comfort Resource guide.
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Energy 1 Heating & Air Conditioning
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