Keeping your home’s indoor air clean and healthy is very important. Since you and your family are breathing that air all the time, you certainly don’t want it to be filled with contaminants such as dust, pollen, mold spores, dander, and various microorganisms.
When you inhale airborne contaminants, it can cause a sore throat, breathing problems, and allergy symptoms like sneezing, coughing, congestion, and runny nose.
To keep your air nice and clean, you need your home’s HVAC system to filter out the contaminants as it cycles. And for it to effectively do that, it needs to have quality HVAC air filters. And this is where the MERV ratings come in.
MERV 8 vs MERV 11 are the commonly used filters in the home. Although they both do the same thing: filter dirt from the air, they do this at different levels. And as you can see, this is because they are different ratings.
Bottom Line Up Front
There is a major difference between MERV 8 and MERV 11, apart from their ratings. So they cannot be compared under any circumstance. Air filters with MERV 8 ratings are suited for homes with normal air situations. If your home is not exposed to any form of contaminants like dust and smoking, then you should go for MERV 8.
However, air filters with MERV 11 ratings and above are only needed in cases where homes are exposed to dangerous pollutants. You can get air filters with a MERV 11 rating if you or anyone around has allergies and if you own pets. It is also good if you or anyone around smokes.
Merve Rating and Air Filters
Your HVAC system’s air filters have a very impactful job. As your furnace and air conditioner circulate air around your house, all that air must pass through the filters. At that point, the filters’ duty is to trap as many airborne contaminants as possible. Then, when you and your family end up breathing that air, it’s as clean and healthy as possible.
If you want to ensure that everyone in your home can always breathe easily, you need to select the right air filter for your HVAC system. The quality of an air filter depends on its MERV ratings. So, MERV 8 filters have a different quality from MERV 11 filters.
What is a Merve Rating, Anyway?
MERV stands for Minimum Efficiency Reporting Value. It is a rating based on how effectively an air filter can trap airborne contaminants.
When considering different HVAC air filters, you’ll notice that they are all given a MERV rating. Every filter will have a MERV rating somewhere between 1 and 20. That number is calculated based on how well the filter can catch particles between the sizes of 0.3 and 10 microns.
The higher an air filter’s MERV rating is, the higher percentage of pollutants it will be able to catch on average.
Two of the most common air filters used in households are MERV 8 filters and MERV 11. Typically, any HVAC air filter rated below MERV 8 will do a poor job of trapping contaminants.
And for regular homes, it isn’t necessary to purchase filters higher than MERV 11 unless your home is constantly exposed to pollution or particles like smoke. Air filters with MERV ratings above 11is are also the best for people with allergies.
If you’re trying to decide which air filters you should invest in for your HVAC unit, you will need to determine what MERV rating you want. Here, we’ll cover the differences between MERV 8 and MERV 11 filters, which should make it easier for you to make the right decision.
MERV 8 Air Filters
First, let’s look at air filters with a MERV rating of 8.
Although a MERV 8 rating isn’t all that high, that doesn’t automatically mean that MERV 8 filters are a bad choice for your situation. These air filters may be a great choice depending on your household needs.
Filtration Efficiency of MERV 8 Air Filters
A big part of an air filter’s MERV rating is its filtration efficiency rating. This rating measures what percentage of airborne contaminants a filter will usually catch on average. For example, if a filter has a filtration efficiency rating of 90%, it will typically catch about 90% of the pollutants that pass through it.
For contaminant particles between the sizes of 3 and 10 microns, MERV 8 air filters will catch up to 70% of them on average. While that isn’t an amazingly high percentage, it also isn’t too bad. For most households, catching nearly 70% of the contaminants will be good enough to keep the air pretty clean.
However, air filters with a MERV 8 rating usually capture less than 20% of particles smaller than 3 microns. That means that these filters will often be unable to catch certain types of pollutants in the air.
Which Contaminants will a MERV 8 Air Filter Catch?
Many different types of contaminants could be floating around your home anytime. These particles come in many different sizes, which directly affects which air filters can trap them. Typically, an air filter with a MERV 8 rating will be able to catch the majority of the more significant pollutants in your living space.
This includes dust, lint, mold spores, pollen, and dust mites. These particles all tend to be larger than 3 microns, so if your HVAC system uses MERV 8 air filters, the filters should be able to catch most of them consistently.
However, some airborne pollutant particles are very tiny. And if they’re smaller than 3 microns, then MERV 8 air filters will have a lot of trouble trapping them.
A few examples of these contaminants are smoke, pet dander, and certain types of bacteria. So, if you have pets or live in an area that regularly experiences smoke, purchasing MERV 8 filters may not be the best choice to keep your air consistently clean.
How Often Should MERV 8 Air Filters be Replaced?
When deciding how often to replace your HVAC air filters, it’s important to remember that every household situation is different. Many different factors can determine how quickly a filter becomes dirty.
These factors include:
- the size of your house,
- the number of people living with you, and,
- how often do you use your heating and cooling systems?
So, different air filters have other guidelines for how often you should change them.
On average, you should replace MERV 8 air filters at least once every three months. But if you want to keep your air as clean and healthy as possible, replacing them every two months could be wise.
Changing the filters out more often during the summer and winter is also a good idea. During those times of the year, you’re probably running your HVAC system more often, which means that the filters trap more contaminants.
Who Should Use MERV 8 Air Filters?
- People with no pets and allergies – MERV 8 filters are an excellent choice for households with average filtration needs. Generally, this means houses without pets and without any residents that suffer from allergy symptoms.
- Homes with no pollution and smoke – MERV 8 filters are also effective for homes in areas with low levels of pollution and smoke in the air.
Overall, HVAC air filters with MERV 8 ratings do an excellent job of keeping indoor air clean. They aren’t the most effective filters on the market, but as long as your household has no special filtration needs, they should be fine.
MERV 11 Filters
Now, let’s cover HVAC air filters with a MERV rating of 11.
A MERV 11 rating is relatively high, and if you don’t feel that MERV 8 filters are effective enough for your needs, MERV 11 filters may be a perfect choice.
Here, we’ll take a closer look at these air filters and what they can offer your home.
Filtration Efficiency of MERV 11 Air Filters
When it comes to contaminant particles sized between 3 and 10 microns, MERV 11 air filters will usually be able to catch around 85% of them.
If the airborne particles are between 1 and 3 microns in size, then a filter with a MERV rating of 11 will typically have success trapping as much as 65% of them. MERV 11 air filters can catch up to 20% of the pollutant particles between 0.3 and 1 micron.
Filters rated at MERV 8 will have trouble capturing any of the particles that are that small. So, there are certain types of contaminants that you may be able to catch with MERV 11 filters but not with MERV 8 filters.
MERV 11-rated air filters have very impressive filtration efficiency. They aren’t at the very top of the heap, but in most situations, they will be able to keep the indoor air quality at a high level.
Which Contaminants will a MERV 11 Air Filter Catch?
If your HVAC system is equipped with MERV 11 air filters, they will be able to catch nearly all of the larger contaminants. Just like MERV 8 filters, these higher-rated filters will trap most of the dust, lint, mold spores, pollen, and dust mites.
Additionally, MERV 11 filters should be able to catch a good amount of the smaller particles, such as smoke, pet dander, smog, auto emissions, and many types of airborne bacteria. Of course, a MERV rating of 11 is not high enough to catch all those tiny contaminants, but it will catch far more than a MERV 8 filter will.
How Often Should MERV 11 Air Filters be Replaced?
You should always remember that there’s no perfect answer for how often you should replace your HVAC air filters. On average, you should MERV 11 air filters at least once every two months. Since filters rated at MERV 11 are better at trapping contaminants, they usually become dirty more quickly than MERV 8 filters.
If you’re using your HVAC system frequently or want to ensure your air stays as clean as possible, you may want to replace the filters more often. Switching the filters to new ones every month wouldn’t be bad.
Who Should Use MERV 11 Air Filters?
- People with pets – HVAC air filters with MERV 11 ratings are perfect for homes with special air filtration needs. For example, if you live in a household with pets, MERV 11 filters will do an excellent job catching their dander.
- People with allergies – These filters can also keep the air enough to keep people with allergies feeling healthy and comfortable. Because of their high filtration efficiency, air filters rated at MERV 11 can maintain clean indoor air in just about every household situation.
- Homes exposed to smoke and pollution – MERV 11 air filters are also an excellent choice for anyone living in an area with mild or moderate pollution. If you live downtown in a big city or your home is somewhere that can become smoky; these high-quality filters should still be able to do an excellent job of keeping your indoor air healthy.
Air filters with a MERV 11 rating are good at catching contaminants like dust, smoke, dander, and even allergens. You should only get it if your home is exposed to any of these.
How Should You Decide Between MERV 8 and MERV 11 Air Filters?
When you’re trying to decide between MERV 8 and MERV 11 air filters, there are a few things you should take into account.
What is the Situation of Your Family?
First, you should consider your and your family’s unique needs. For example, consider whether or not you have pets and whether or not anyone in your household has allergies or asthma.
If you answer yes to any of those factors, you should use MERV 11 filters. But If this is not your situation, then MERV 8 filters are just fine for your situation.
What is Your Home’s Environment?
It would help if you also considered the environment where you and your family live. It’s essential to consider whether there’s much pollution in your area’s air. Going with a higher MERV rating would probably be wise if you live in an industrial area with lots of smog in the air.
The same goes if you live somewhere that regularly experiences smoke from wildfires. However, if you live in a country surrounded by fresh, clean air, you may not need anything higher than MERV 8 filters.
Finally, it’s important to remember that you don’t have to decide on your own. If you’re struggling to decide which HVAC air filters to purchase, you can always get professional help.
Many HVAC contractors offer indoor air quality services. If you call your local experts, they should be able to visit your home, evaluate your situation, and give you a recommendation.
Question: Do All Types of Air Filters Use the Same Amount of Energy?
Answer: In short, the answer is no. When HVAC air filters remove contaminants from the air, they provide resistance to the atmosphere. The higher the MERV rating of the filter, the more resistance there will be, and the harder the HVAC system will have to work to do its job.
So, technically, air filters with higher MERV ratings will cause your HVAC unit to use more electricity. That will result in your monthly energy bills being more expensive.
So, while MERV 11 air filters will trap more contaminants than MERV 8 air filters, they may cost you more money to use in the long run.
Question: Is a Higher MERV Rating Always Better?
Answer: It depends on how you look at it. When trapping more airborne contaminants, an air filter with a higher MERV rating will always be more effective. However, that doesn’t mean filters with higher MERV ratings are the best choice for every household. If you don’t have special filtration needs, you can usually save money using lower-rated air filters.
Also, because filters with higher MERV ratings will make your HVAC unit work harder, the risk of a system malfunction or breakdown may increase. So, your heating and cooling systems may have longer lifespans if you use MERV 8 filters instead of MERV 11.
Question: Do Air Filters with Higher MERV Ratings Cost More to Purchase?
Answer: The answer is almost always yes. Generally, the purchase price will also rise with every point that the MERV rating rises. And since air filters with higher MERV ratings need to be replaced more often, you will need to spend that money several times each year.
So, when deciding between MERV 8 and MERV 11 air filters, you have to decide if it’s worth spending more money for the higher rating. If your main priority is clean air, it’s worth the extra cash for MERV 11 filters.
However, if you don’t need the higher filtration efficiency, there’s a good chance you’ll be better off going with MERV 8 filters.
Ultimately, both MERV 8 and MERV 11 HVAC air filters have advantages and disadvantages. Every household situation is unique, and you should never rush into a decision when choosing which filters to invest in. Your choice can affect your health, comfort, and finances, so it’s worth considering your options.
Air filters with MERV 8 ratings are perfect for you if your home is not exposed to contaminants. But if you have a pet, smoke, or have someone who does a lot, then you should go for MERV 13 air filters. MERV 13 air filters will also be perfect if you have allergies or asthma.