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The time has come for you to change out your furnace’s air filter. You might be tempted to walk right into the closest hardware store and buy the first filter you find on the shelf. However, you might want to pause for a moment to consider which type of filter your home needs. There are multiple types of filters, and the one you choose does matter.
Not all filters are made equal. In fact, some of them do a much better job of filtering particles out of the air than others. During your search for the best home air filter, you might come across two types of filters: MERV and HEPA. They are both commonly used, but they have their differences. Which one you should get depends heavily on whether you are in a residential or commercial setting.
Which type of filter should you use? Which one is the most effective at filtering out particles and keeping your home’s air clean and fresh? Let’s get down to the nitty-gritty and go over the ins and outs of MERV and HEPA filters.
MERV and the Rating System
MERV is actually a rating system with a couple of different types of MERV filters available. They are really just air filters with their own MERV ratings. The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) created minimum efficiency reporting value (or MERV for short) as a way to report measurements and compare their abilities to capture particles sizing between 0.3 and 10 microns.
The MERV scale starts at one and ranges up to 20, with 20 being the filter with the highest degree of particle capture. A MERV filter rated one to four can filter out textile fibers, pollen, dust, and dust mites. Up a level from that are MERV five to eight filters. These are able to filter out furniture polish and mold spores. Lead dust and exhaust fumes can be captured by MERV filters rated 9 to 12.
If you need a filter that captures tobacco smoke, airborne bacteria, or respiratory droplets, then a MERV 13 to 16 filter is going to be a stronger option than a lower-rated MERV filter. MERV filters rated 17 or higher are able to filter out microscopic allergens and airborne viruses, including COVID-19.
Do HEPA Filters Have MERV ratings?
HEPA – an acronym for high-efficiency particulate air – filters are able to capture 99.7% of air pollutants that are as small as 0.3 microns. Because they are so effective and efficient at air filtration, they are often used in commercial spaces where the cleanest air possible is needed, such as in a hospital’s emergency room or operating room. Overall, HEPA filters have earned a good reputation for their capabilities.
That being said, HEPA filters do not have MERV ratings. This is due to the fact that their capabilities go beyond what the ASHRAE Standard rating system measures. Theoretically, should HEPA filters receive a MERV rating, they would be in the MERV 17+ range. Anything that is MERV rated 16 or below is considered effective for use in a residential HVAC system. However, spaces in which high degrees of filtration are needed for health and safety reasons (such as an operating room) are best fit for these non-MERV-rated filters.
MERV or HEPA: Which Filter Is Best for You?
When it comes to a MERV filter, the ideal fit for just about any home is going to be a MERV 11 to 13 filter. These do a good job of getting undesirable particles out of the air and keeping it fresh for quite a while. If you buy something with a lower MERV rating, you will find yourself needing to replace it much more frequently than you would like. They can also be more expensive and less effective in the long run.
HEPA filters are best left out of residential HVACs. They are actually so powerful that they will reduce the air flowing through a home’s HVAC system. This forces the HVAC system to work overtime just to pump enough air through the HEPA filter. You don’t want to push your HVAC system to work extra hard at pushing air through since this can cause bigger problems stemming from the lack of efficiency.
What’s more, HEPA filters are not compatible with most home HVAC systems. If you wanted to convert your home’s HVAC to accommodate HEPA, you would have to drop a serious chunk of change on the retrofitting and additional fans required to filter out the air. Since HEPA is not really compatible with residential HVAC systems, it is best that you avoid getting one put in. As a service technician will tell you, a MERV filter ranging from 11 to 13 is going to be your best bet.
What About FPR-rated Air Filters?
There is one more acronym that you should know about regarding air filters. A filtration performance rating — or FPR — is a measurement of an air filter’s ability to capture big and small particles. Also measured is its pressure drop (which basically refers to the filter’s resistance as it catches smaller particles) over time.
Ratings range from 4 to 10, with 10 being the most efficient filter. A filter rated FPR 4 or 5 can catch big particles but struggles to capture smaller ones. They are best used in a space where regular cleaning takes place since dust reduces their efficiency over time.
On the other hand, a filter rated at FPR 6 or higher can, in the average home, trap about 85% of particles in the air. They offer more longevity than lower-rated FPR filters but will still degrade as time goes on. An FPR 4 filter lasts about four to six months whereas an FPR filter with a rating over 6 can last up to about three years. You will need to be mindful about changing your filter out on a regular basis no matter which one you get put in.
Buying the Best Filter
Quality matters when buying the best air filter. That is why we here at Black-Haak in Greenville, WI, sell a selection of filters that meet our high standards for filtration. Our goal is to keep your HVAC system running at an optimal level, and that means installing a high-quality filter to get the job done. We only sell brands that we know and trust so that you can get the most efficiency possible.
When you call on us to help service your HVAC system, we can give you a better idea of which size filter you will need. There are many good options to choose from, and what you get will depend on your home’s unique needs (such as having multiple pets or someone in the home having respiratory issues).
Along with heating and air services, we also offer a complete lineup of plumbing and electrical solutions. Don’t hesitate to contact Black-Haak to schedule your HVAC service today.
