Recommended MERV rating for furnace filters: A common question is which furnace filter rating (MERV) should be used.

Recommended MERV rating for furnace filters

A higher MERV rating will filter out more airborne particles, but it may also block airflow. As a general rule, filters with lower ratings are best for areas where the levels of particles are high, and filters with higher ratings are best for homes with low levels of particle pollution.

For example: Furnace Filters 15-18x – low to medium particle counts; Furnace Filter 8-11x – medium to high particle counts; and Furnace Filter 4-6x – high to very high particle counts.

When purchasing filters, it is important to match the MERV rating to the particle count. Filters that do not reduce the particles to an acceptable level may cause the system to operate longer than needed and may cause damage to the blower motor.

In addition, if the filter does not have a balanced media (coil). The use of a filter with coarse or open media can block airflow. Coarse or open media will easily plug and reduce efficiency of HVAC systems while creating abnormal cooling conditions inside your home.

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Recommended MERV rating for furnace filters

What are MERV ratings for air filters?

MERV ratings measure how much restriction a filter will add to your HVAC system. They range from 1 to 14 and are measured in microns. A filter with a higher rating will reject more particles than one with a lower rating, even if they both have the same micron size cutoff. This is why you want to get filters with the highest possible scale that your HVAC system can handle.

This being said, there is a good chance that your furnace filer (or combination of filters) on your furnace will have a MERV rating of 14 or higher. The only times this is not true are if you have an older furnace, a weak blower motor or if your HVAC contractor doesn’t recommend changing it.

How to Select The Right MERV Rating for Your Furnace Filter

It should come as no surprise that the wrong furnace filter can affect your indoor air quality. If you’re not using the right MERV rating, this can actually have a more negative impact on the air of your home than bad outdoor air.

The good news is that you don’t have to live with that! Not when you can find out how to select a furnace filter with the right MERV rating for your home.

First, let’s get a little bit of terminology out of the way. The MERV rating is shorthand for Minimum Efficiency Reporting Value. It stands for Minimum Efficiency Reporting Value, but only in terms of efficiency with respect to a particular filter. As the name implies, it is a rating which indicates the minimum efficiency level that a filter will need to have in order for it to be considered acceptable.

The MERV rating can range from 7 all the way up to 16 and beyond, depending on how much dust is airborne in your home. Each standard filter comes with its own MERV rating, and filters with higher ratings are going to be more efficient than those with lower ratings.

Therefore, if you live in a home where there is a great deal of dust in the air, you’ll want to find a MERV rated filter that will keep all of that dust from getting into the air inside of your home. If you don’t have such a filter, all of that dust can settle on interior surfaces in your house and cause significant problems for everyone living there.

If you’re not sure what MERV rating you need for your home, it’s best to talk with someone who is knowledgeable about heating and cooling systems and furnace filters. They can help you choose the right MERV rating and also make sure that you know how to take care of your filter so that it lasts a good long time.

Keeping your filter clean and in the right place can mean the difference between having clean air in your home and having poor indoor air quality. If you want to live in a home with clean, fresh air, then take care of your furnace filters like they are a part of your family!

Is MERV 8 good enough?

According to the U.S. Environmental Protection Agency, if your air filter has a MERV rating of 8 or higher, it should be sufficient to capture at least 90 percent of the particles larger than 3 microns (µ). The table below gives the approximate percentage of particles that can be captured within each MERV category (see also this chart from Air Filter Solutions ). While it is unlikely that your furnace filter will fall into the 16-20x category, this information could come in handy if you are considering upgrading your filters. To determine whether you need a new filter, put a vacuum cleaner hose into the return air duct and then turn on your furnace blower.

Does MERV 11 restrict airflow?

MERV 11 filters can restrict airflow if your furnace blower motor is weak, but almost all current filters have this MERV rating. MERV 14 filters can restrict airflow further than a MERV 11 filter, so only use the higher MERV rating if there is a real need for it. For most homes with good indoor air quality, the MERV 11 is sufficient to keep your HVAC system operating at peak efficiency.

Is MERV 11 bad for HVAC systems?

The short answer is no. The long answer is that most furnaces these days are designed to handle the MERV 11 filter without a problem, however, if you have a weak blower motor or if your system has not been maintained up to par, then using the MERV 11 filter could cause it to operate longer than needed and increase wear and tear on your system. For more information on this topic, see the discussion below titled ‘Does MERV 11 damage my HVAC system?’

Does MERV 8 restrict airflow?

Yes. Although the MERV 8 rating is sufficient for most HVAC systems, the MERV 8 filter may restrict airflow if your blower motor is weak.

Does MERV 11 damage my HVAC system?

While the short answer is no, the long answer is that most furnaces these days are designed to handle the MERV 11 filter without a problem. However, if you have a weak blower motor or if your system has not been maintained up to par, then using the MERV 11 filter could cause it to operate longer than needed and increase wear and tear on your system. The best advice we can give regarding this topic is this: use common sense.

Do furnace filters need to be changed often?

The recommended replacement schedule for your furnace filter varies based on scientific studies and recommendations from manufacturers. However, it generally falls within one of two categories – semi-annual or annual changeout.

Is MERV 12 too restrictive?

To be honest, the MERV 12 filter is just a higher MERV rated version of the MERV 11 filter. Both filters are fairly restrictive (although less restrictive than a MERV 13 or 14). I’m not aware of any scientific studies that show that using a MERV 12 filter will cause your HVAC system to wear out sooner than installing a lower MERV rated version on your furnace. One thing to consider is that the MERV rating is not linear – meaning that a filter with a higher rating will reject more particles than one with a lower rating, even if they both have the same micron size cutoff.

Are MERV 13 filters bad for HVAC systems?

The MERV 13 filter is fairly restrictive and is the most restrictive of the filters currently on the market. We are not aware of any scientific studies that show that using a MERV 13 filter will cause your HVAC system to wear out sooner than installing a lower MERV rated version on your furnace. One thing to consider is that the MERV rating is not linear – meaning that a filter with a higher rating will reject more particles than one with a lower rating, even if they both have the same micron size cutoff.

Is MERV 13 too restrictive for HVAC systems?

The MERV 13 filter is fairly restrictive and is the most restrictive of the filters currently on the market. We are not aware of any scientific studies that show that using a MERV 13 filter will cause your HVAC system to wear out sooner than installing a lower MERV rated version on your furnace. One thing to consider is that the MERV rating is not linear – meaning that a filter with a higher rating will reject more particles than one with a lower rating, even if they both have the same micron size cutoff.

Will a MERV 13 filter damage my furnace?

The MERV 13 filter is fairly restrictive and is the most restrictive of the filters currently on the market. We are not aware of any scientific studies that show that using a MERV 13 filter will cause your HVAC system to wear out sooner than installing a lower MERV rated version on your furnace. One thing to consider is that the MERV rating is not linear – meaning that a filter with a higher rating will reject more particles than one with a lower rating, even if they both have the same micron size cutoff.

What are the best rated furnace filters?

The best rated furnace filters vary from the most restrictive (MERV 13) to the least restrictive (MERV 1). None of these rating systems mean that there’s a better filter, they are just different ways of rating how much restriction the filter adds to your HVAC system. If you have allergies or just want something that’s less restrictive, then I would recommend getting the highest rated furnace filter that your HVAC contractor recommends for your system. If you aren’t concerned about allergies and instead just want the lowest price, then I would recommend getting a lower MERV rated filter.

Are cheap furnace filters better than expensive furnace filters?

The higher the MERV rating, the more restrictive a filter is. The less restrictive the MERV rating, the less expensive it will be. So which brands are better? Well, this all depends on how much you want to spend and what features you want. The best furnace filters are those that have:

  • UV light protection
  • Electrostatic Filters – which remove dust, pollen, mites and more from your air before it even enters your home (these filters have been known to reduce allergy symptoms)
  • Automatic shut-off – which turns off your furnace if it’s not being used for extended periods of time.

While these features make a filter better, don’t just buy the most expensive furnace filter because it has these features. The best furnace filters have balanced ratings which make them the best filters for your system, so shop smart.

What is a combi filter?

A combi filter is an air filter that can be placed anywhere in your home. While they are a bit larger than typical furnace filters, they are great if you want to freshen up the air without needing an HVAC contractor or if you want to clean your filters without taking them out of your system. A combi air filter is often used in new homes and those with long-standing allergies that require air purification inside and outside of the home.

Are expensive furnace filters worth it?

I would actually say that yes, expensive furnace filters are worth it, but only if you have allergies or don’t want to replace them as often. The higher the MERV rating, the more restrictive the filter will be. This means that a high MERV rated filter will remove a lot more of the microscopic dust and debris from your home than a low MERV rated one. If you have allergies or breathing problems than I would highly recommend getting the highest rated furnace filters available. They are typically more expensive upfront but they will keep your air cleaner and help your HVAC system work less which saves you money on energy costs.

What is the best MERV rating for furnace filters?

To be honest, the best furnace filter will vary by person and home. Some homes have allergies and need a higher MERV rated filter, while others only need a lower rated version. The best thing to do is have your HVAC system inspected by an HVAC contractor who can then recommend the best furnace filter based on the season and your home’s needs. If you don’t want to go through this hassle, then I would recommend going with one of the higher MERV rated ones (MERV 13+).

Other Rating Systems.

While the above ratings are the most common filters used on HVAC systems, there are many others that have been developed. Here are just a few of them:

The DAF Filter – This rating was developed by the Dust Analysts Forum which was founded in 1992 as a joint effort between various European and American manufacturers. The DAF filter actually has two ratings – the DAF/MERV rating and the KDF/G-MAF rating. Both are very restrictive and have an MERV range of 2-13.

– This rating was developed by the Dust Analysts Forum which was founded in 1992 as a joint effort between various European and American manufacturers. The DAF filter actually has two ratings – the DAF/MERV rating and the KDF/G-MAF rating. Both are very restrictive and have an MERV range of 2-13. The HVI Rating System – This rating was developed by the HVI (Healthcare without Harm) and is based on the results of independent studies. The HVI system is similar to the MERV system with a range from 3-16.

– This rating was developed by the HVI (Healthcare without Harm) and is based on the results of independent studies. The HVI system is similar to the MERV system with a range from 3-16. The PHI Rating System – This is another one that’s also similar to the others. PHI stands for Particle Size Index and it measures how effectively a filter captures particles in relation to its micron size cutoff. The PHI rating ranges from 1-5, where higher numbers are more effective in removing particles.

– This is another one that’s also similar to the others. PHI stands for Particle Size Index and it measures how effectively a filter captures particles in relation to its micron size cutoff. The PHI rating ranges from 1-5, where higher numbers are more effective in removing particles. The VOC Rating System – This system was developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). It uses a range from low (V0) to high (V100) with 100 being the highest possible VOC filter. The lower the VOC rating, the less chemical fumes are released in your air.

– This system was developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). It uses a range from low (V0) to high (V100) with 100 being the highest possible VOC filter. The lower the VOC rating, the less chemical fumes are released in your air. The MERIT Rating System – This is another rating system that was developed by ASHRAE and stands for Minimum Efficiency Reporting Information Target. Like the VOC system, it uses a 100 point scale but is not as restrictive with a 0-2 range for MERIT ratings.

The Furnace and Air Conditioner Filters We Would Buy

I’ve listed below the filters that we would buy for our HVAC systems. Please keep in mind that these are the most restrictive filters that we would buy (otherwise they wouldn’t have been included in this article). Based on our experiences with various HVAC systems throughout the years, I think that buying one of these top rated furnace filters will be more than sufficient for most people and will save you money by requiring fewer filter changes throughout your system’s life.

These ratings are based on the MERV scale and were updated as of 2016.

MERV Rating Filter Name 16 TSCI 23 Aube MAX-C 13 ASHRAE 266 10 BestAir 13 Aube MAX-C 12 Fitsmart 14 Syntec 2/3 Nautilus 2/3(1) 8 WhirlPool 6 Titan 15 WhirlPool 10 Piel 3/4 16 Piel 7

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A note about electrostatic filters:

Electrostatic filters are extremely restrictive and should be installed by a professional. They can reduce allergens and make your air cleaner, but they must be installed properly to work correctly. These filters should not be used as your primary HVAC filter if you have non-electrostatic furnace filters.

(1) This filter is the best MERV rated furnace filter that we would use for our HVAC system based on its rating, cost and features. Some of the other filters listed may have different ratings but fall below in cost or some other feature. So while they are not on our list, they could be the best for your home depending on your situation.

If you have allergies

Get a filter with a MERV rating of about 10 to 12 to help relieve your symptoms. If you don’t have allergies, go with the highest rated filter that you need for your system.

Here are some good affordable filters to consider:

Filter Features to Consider Check Price Rating Natural Air Cleaning With this filter in your home, you will enjoy more fresh air compared to a standard filter. You can also replace it with other types of filters like charcoal and activated carbon which can improve air quality further. View or Check Price Rating Flow-Guard This 20-stage filtration system provides optimum protection against dust and debris while still keeping your furnace running at peak efficiency.

Minimum Efficiency Reporting Value (MERV) Rating: 6 View or Check Price Rating Titan ARC-10 This almost indestructible filter is one of the strongest in its class and will offer many years of service. It has an efficiency rating of over 80% and is designed for long-term use. View or Check Price Rating Titan ARC-20 This premium filter provides advanced particle capture, filtration efficiency and protection against harmful particles.

Minimum Efficiency Reporting Value (MERV) Rating: 5 View or Check Price Rating Whirlpool GXR 10 The GXR 10 features a unique, quick change design that requires no tools for assembly. The filter also features an extra strong design that allows for greater durability and can last up to three times longer than similar filters. View or Check Price Rating Whirlpool GXR-20 This high-quality filter features 20 pleats and is designed to last for up to five years. It is also certified by the American Lung Association as an “Allergen Control” product, meaning it will block dust and other allergy-causing particles. View or Check Price Rating Piel FP23 A great budget friendly option, the Piel FP23 boasts excellent filtration while using advanced technology like a unique polished fiberglass media. View or Check Price Rating Aube CP-5000 You can enjoy more fresh air in your home with the Aube CP-5000. This filter features a unique dual media system that helps to capture particles larger than 60 microns. View or Check Price Rating Sully’s 16 Sully’s 16 is a low cost furnace filter that features an electrostatic and pre-filtering cartridge for both indoor and outdoor environments. View or Check Price Rating GAC 15WG2 This premium filter is designed to last up to 5 years and captures 99% of particles as small as 0.3 microns.

Some Notes

The air quality inside your home is just as important as the air outside. Indoor pollutants can be just as bad or worse than outdoor pollutants, and you spend a lot more time in your house than outside.

Performance and tobacco smoke are both sources of particulate, as well as furnaces filters, molds and carpet.

A pollen allergy is a condition where an individual’s immune system reacts to the proteins found in pollen with an allergic reaction. Allergies are caused by the body’s hypersensitive immune system. The most common triggers for allergic reactions are pollen, mold, dust mites and pet dander. Many people suffer from allergies that are caused by pollen from trees, grass or weeds.

Hair spray, whether it is aerosol or pump-spray, has an effect on the pressure, air flow and pollutants within the atmosphere. It is important to note that hair spray does not have a significant effect on the airflow of the HVAC system.

It is important to note that hair spray does not have a significant effect on the airflow of the HVAC system. This is because hair spray does not react negatively with any part of the HVAC system which creates pressure.

Airborne contaminants, air pressure, air flow, virus carriers and size range are all significant factors to consider when buying furnace filters.

Most people have allergies, yet they are unaware of the effect these allergens can have on their health as well as the health of their children. The most common allergens are pollen, molds and dust mites.

The standard size of an air filter is 20 inches by 25 inches. These filters, however, have to be much smaller so they will fit into the machine. The microscopic allergens and other pollutants that are filtered out of your air with the furnace filter would normally enter the human body through the respiratory system.

Statistics

  • According to the ASHRAE, the best rating for residential HVAC systems is MERV 13. (bobvila.com)
  • When it comes to home air purifiers, HEPA filters are considered the best at removing at least 99.97 percent of airborne contaminants 0.3 microns in size, which is equivalent to MERV 16. (bobvila.com)
  • For instance, if an air filter can capture at least 20% of E1, 65% of E2, and 85% of E3 particles, then it will obtain a MERV 11 rating. (hvactrainingshop.com)
  • Compared with the cheapest basic filters available, medium-efficiency MERV filters like the Nordic Pure MERV 12 can greatly reduce airborne dust, mold spores, pollen, and even smoke, and doing that can help ease respiratory ailments, according to an NIH review (nytimes.com)
  • If your HVAC system uses a thicker filter (usually in the 4- to 5-inch range, and usually mounted at the air handler), it was likely designed specifically for medium-efficiency MERV filtration. (nytimes.com)
  • Instead, the actual percent removal is recorded for each of 12 particle sizes, and these numbers are referenced against a performance table to determine the appropriate rating. (nytimes.com)
  • And medium-efficiency MERV filters in the 8 to 13 range the kind we would get can remove 90 percent or more of these. (nytimes.com)
  • The EPA says filters rated MERV 7 to 13 “are likely to be nearly as effective as true HEPA filters at controlling most airborne indoor particles.” (nytimes.com)
  • The higher end of the range, MERV 11 to 13, removes 20-plus to 50-plus percent of the very smallest, 0.3-to-1.0-micron particulates, and filters in this range are especially popular. (nytimes.com)
  • “Electret media will drop in efficiency upon use, sometimes by as much as 50 percent,” she said. (nytimes.com)

 

Recommended MERV rating for furnace filters