MERV vs. MPR vs. FPR: What Air Filter Rating Should I Choose

Air filters are a key component in any air conditioning system. It’s something most homeowners will be very familiar with, but it’s also an area that can be incredibly confusing. That’s because there are different standards to keep up with, which is why you’ll see some air filters with a MERV rating, while others are listed as MPR or FPR.

That means finding the right air filter to fit your needs, isn’t as easy as it used to be. If you’ve been troubled by the MERV vs. MPR vs. FPR comparison, we’re here to help clear things up. Whether you’re wondering if you should choose a MERV 6 or if an MPR 1200 is right for you, we’re going to tell you what to look for in order to find the right filter rating for your home.

Understanding Air Filters

An air filter is a simple but incredibly effective device. Simply put, air passes through an intake before going through the filter and recirculating back into your home through registers. As it’s forced through your system and passes through the filter, the air filter traps particles and dust before they enter your home.

The right filter can capture everything from dust mites to pollen, and while simple, they do have to be changed on a regular basis. Otherwise, you could end up spending hundreds of dollars on a repairman or encounter a variety of other issues.

The Importance of Air Filters

A new central air condition system or heat pump can cost thousands of dollars, whereas a good air filter will only set you back between $5 to $20. They are also a critical part of your HVAC system, as it does more than just freshen up the air in your home. Before we talk about MERV vs. MPR vs. FPR, we’re going to tell you why choosing a good air filter is crucial.

Indoor air quality is important in any home, but even more so if you spend more time indoors than outside. Do you suffer from allergies or have pets? If so, there are air filters made for that, and changing them on a regular basis can reduce your sniffles considerably.

If you have ever looked at a dirty air filter that’s lived past its expiration date in your home, you should already understand why IAQ is so important. You’ll breathe better, sleep better, and the air will smell fresher throughout your home when you have a clean air filter with the right rating.

Another major reason to keep your filter clean is efficiency. A dirty filter can bog down your system and make it run harder or longer than it normally would. That will cost you money over time, which defeats the purpose of buying an energy-efficient unit that’s supposed to save your family money each month. It can also keep the repairman from making a costly trip to your home.

While there are many points of failure on HVAC systems, the biggest problem is usually negligence. There are a few things you’ll need to do throughout the year if your unit is located outdoors, but changing the filter regularly should be at the top of your to-do list. The filter can act as a shield to keep debris from entering your system or the ductwork, although it’s important to install a filter that’s the right size and rating as well.

When Should I Change My Air Filter?

That’s the most asked question from our readers, and it’s something you should ask yourself if you want your HVAC system running at peak performance. Unfortunately, it’s the one thing most homeowners forget, although we have a few tips to help keep you on track.

On average, you should change your air filter every 30 days if it’s made from fiberglass or is considered a “cheap” filter with a low rating. If you’re not sure what falls into that category, take a look at a filter that costs $5 compared to one that’s $20 with a high MERV 13 rating.

With high-end filters, you can go for months, up to 6 months in some cases, before needing to change it out. That said, those estimates are based on general use and don’t take into account things like smoking or pets. If you have allergies or children, you may need to change it sooner as well. Are you doing any remodeling in your home? Well, you’ll definitely want to check out the filter once your project is complete and while it’s in progress.

If you run your system frequently, the filter may need to be changed more often as well. One of the best tips we can give you is to use the spot on the side of the filter with a date to keep track of when your air filter was installed. That gives you a way to keep track of time, but we also highly advise a visual inspection with expensive filters every few months. If you notice a change in the quality of the air in your home, always check the filter first.

MERV Air Filters

MERV stands for Minimum Efficiency Reporting Value. This standard was introduced in 1987 by the American Society of Heating, Refrigerating, and Air Conditioning Engineers as a way to rate the effectiveness of air filters. Considering the ASHRAE has been in existence since 1894, it’s safe to say they understand heating and air.

The MERV rating scale is recognized nationally, so if you buy a filter rated at MERV 8 from one manufacturer, it will be the same from another. MERV filters are rated on a scale of 1 – 20, with levels that tell you how much they can block or capture.

On the low-end are fiberglass filters, which are 1 – 4 on the MERV scale. They block things like carpet fibers, dust mites, and pollen but will need changed more often and aren’t ideal if you want good IAQ. They are cheap, but better suited for window AC unit than an HVAC system.

merv rating 8 vs 11 vs 13

Filters in the 5 – 8 range can block smaller particles, which means they cover mold spores, dander, and dust from your household along with dust from food items like pudding mix. These filters can capture hair spray and dusting agents from aerosol cans as well. They are an excellent fit for most homeowners, but not as powerful as the next tier.

MERV filters from 9 – 12 provide excellent filtration for homeowners but can get expensive if you need to change filters frequently. They can handle smaller airborne particles from 3.0 to 1.0 μm and are found in commercial settings considering they can block lead dust or even legionella and other bacteria.

When you want superior air quality or your home to need to clean the air in your smoking lounge, consider MERV filters rated from 13 to 16. They capture particles larger than 0.3 micrometers, which covers everything we’ve mentioned along with smoke and droplets from sneezing. It won’t protect you from the Coronavirus, but they will make your air a whole lot fresher.

Any filter with a MERV rating over 16 could be overkill in your home, and they are expensive. While they are available, a MERV 20 filter is better suited for cleanrooms and commercial usage where maximum filtration is required – not necessarily your home.

MPR Air Filters

If you see an air filter that has an MPR rating, which means Microparticle Performance Rating, it’s from Filtrete and 3M. Only these filters can have an MPR rating as it’s their own standard. While similar to MERV in regards to what they block, they are difficult to compare because of a lack of third-party testing. The MPR air filter scale also takes a different route with a range from 100 – 2800. Just like with MERV filters, the larger the number, the better the filtration.

The most basic and cheapest form of filtration from 3M are filters rated from 100 to 300, which covers lint and general dust. If you need to remove pollen or pet dander, you’ll want to step up to a 600 MPR filter, although a filter rated at 1200 can handle smoke, smog, and particles from sneezing or coughing. 1500 class filters add virus protection to a limited degree.

The 1500 filters are also where “Smart Filters” come in play for Filtrete and 3M. These filters actually have built-in Bluetooth, which allows it to keep tabs on your airflow and notify you when it’s time to change the filter. Smart filters are nifty, although a bit more expensive and only available on their premium lines, including the 1900 and 2200.

Those filters are a slight bump up from the 1500’s they cover candle soot, air pollution, and exhaust particles while the 2800 filters can block ultrafine particles. They are available in a half-dozen sizes and are also certified as asthma & allergy friendly by the AAFA. They also have an Ultra Allergen Healthy Living filters that are certified at 1500 and 1900 MPR as well.

MPR Air Filters

FPR Air Filters

The last rating system comes from an unlikely source – the folks at Home Depot. They decided to join the club with their own set of standards dubbed FPR, which stands for Filter Performance Rating. It’s far easier to keep track of if you’re just looking for a simple system, and there are a lot of options to choose from with well over a dozen brands.

Filters from Home Depot are rated on a scale from 1 – 10, and while they sell plenty of filters rated below a 4, that’s where the good ones start. If you do want something cheap, they have fiberglass filters around a buck, however. According to Home Depot, filters in the “Good” class are rated listed as FPR 4, and they will block pet dander, dust, and pollen.

home depot fpr

The next tier is the Better represents 6 – 7, but is listed at 7 FPR, and adds protection against bacteria along with mold spores. Allergies sufferers will want to look for a filter rated at FPR 9. That handles everything the previous levels can block, but also deals with allergens, smaller particulates, and smoke. Their Premium filter range blocks a few things and also clears up odors in your home.

Choosing the right Air Filter


Now that you understand all three rating systems, it’s time to think about which rating is right for your home. As mentioned, there are plenty of cheap air filters available, but we’re going to stick to filters rated that are at least a MERV 6 or above. Keep in mind, the more contaminants a filter can block, the more expensive it will be.

When to choose MERV 6 (comparable to MRP 300)

If you don’t have allergies, a MERV 6 air filter may be the best option for your home. While it’s the bare minimum, we would recommend for residential usage, dust, lint, and pollen along with pet hair. Filters in this range are affordable, and far more efficient than cheap fiberglass filters.

A comparable filter from Filtrete would come from filters in their 100 or 300 series. Alternatively, Home Depot’s filters would be in the Good category at FPR 4 or 5, which is dominated by brands like Honeywell and Nordic Pure.

When to choose MERV 8 (comparable to MRP 600/FPR5)

Pet dander can wreak havoc on your sinuses, and our furry friends can shorten the lifespan of an air filter as well. A MERV 8 filter can still handle lint, dust, and pollen when spring rolls around, but you won’t have to worry about dust mites or mold in your home.

That makes them ideal for homeowners with pets that want something a little better than average, but still affordable. An FPR 7 filter from Home Depot should have similar performance, and you’ll need to step up to the 600 series if you want to go with 3M and Filtrete.

When to choose MERV 11 (comparable to MRP 1000-1200/FPR7)

When you’re worried about dander and dust and want maximum protection, it may be time to choose a MERV 11 filter. Filters in this range tend to be pricy but can last quite a while, depending on your usage. They block all the common contaminants but are better suited for homeowners that have allergies or other conditions that make IAQ vital.

Home Depot’s answer to these filters are air filters rated at around FPR 8 or 9, which puts them into the Best category at the hardware store and opens the doors to some new brands and styles. The equivalent from 3M would be the 1000 class filters including a deep filter, and one that’s geared for heavy household dust.

When to choose MERV 13 (comparable to MRP 1500-1900/FPR10)

If you want to make sure your indoor air quality is pristine, you’ll want to try and find a MERV 20 filter, but will more than likely have to settle for a MERV 13. These filters, and their counterparts, can trap viruses, bacteria, smoke, smog, and other particles that will slip through the cracks of weaker filters.

Filters rated at a MERV 13 should be easy to find, but anything higher could be hard to get your hands on in a local hardware store. For the Filtrete version of a MERV 13, you’ll want to start with a 1500 series filter and work your way up depending on how much you want to spend. From Home Depot, check out the filters rated at FPR 9 and FPR 10.

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications.

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