Most people do not realize their HAVC system’s air filter plays a major role in the quality of the air they breathe. When the air in your home is nice and clean, you probably won’t notice it much. But, you will notice when the air is filled with contaminants.
Breathing in pollutants like dust, mold spores, pollen, and microorganisms can result in physical complications. One of the many reasons for this is having the wrong MERV-rated air filter.
As an HVAC specialist who is also allergic to dust mites, I have a lot of experience with air filters. If you want to know which air filter is best for your home, this article contains everything you need to know about MERV 8 and 13 air filters.
Bottom Line Up Front
MERV 8 air filters are exactly the opposite end of the spectrum of MERV 13 air filters. MERV 8 filters are best for homes with no need for intense filtration because they can only catch the majority of bigger microns. On the other hand, MERV 13 air filters are best for homes in serious need of filtration. They are capable of catching contaminants as tiny as allergens and viruses.
If you do not mind the price, I suggest you go for MERV 13. Also, before making any decisions, you must verify whether or not your HVAC system is compatible with the filter.
Main Differences between MERV 8 vs MERV 13
The main differences between MERV 8 vsMERV 13 are:
- MERV 8 filters are affordable, whereas MERV 13 filters are more expensive.
- MERV 8 filters can only catch bigger particles, whereas MERV 13 filters are good for catching tiny particles.
- MERV 8 filters can be replaced every 2 to 3 months, whereas MERV 13 filters must be changed monthly.
In general, MERV 8 and MERV 13 serve different purposes. MERV 8 filters can only catch bigger particles. While MERV 13 filters catch the majority of smaller particles.
What Is the Job of the Air Filter?
To keep your home’s climate comfortable, your heater and air conditioner must cycle warm and cool air around the house. Without proper air filters, the air will contain lots of contaminant particles. However, if you have high-quality air filters on your HVAC system, they will catch the majority of those particles.
There are many different types of air filters available on the market. Some do a better job catching contaminants than others. But all air filters have their pros and cons. When purchasing a new filter for your HVAC system, you must consider which type fits your situation best.
What Are MERV Ratings?
MERV stands for Minimum Efficiency Reporting Value, which measures how effectively air filters do their job. The better a filter is at catching airborne contaminants, the higher its MERV rating will be. These ratings can be anywhere from MERV 1 to MERV 20. You should decide what MERV rating you want as you shop for different HVAC air filters, depending on your home’s specific situation and needs.
How Is the MERV Rating Determined?
An air filter’s MERV rating is determined by how well it catches particles sized between 0.3 and 10 microns. You may be wondering what a micron is. A micron is a unit of measurement used to measure the size of very tiny objects, like dust mites, mold spores, bacteria, and other small particles.
What MERV Ratings are Best for Homes?
When it comes to residential homes, most will use HVAC air filters somewhere between MERV 8 and MERV 13. Usually, any filter below MERV 8 will have trouble keeping the air consistently clean. Filters above MERV 13, on the other hand, are extremely effective, but they’re usually unnecessary for households. So, you should use MERV 8 or MERV 13 air filters for your home’s HVAC system.
MERV 8 Air Filters
We will start by looking at air filters with a MERV 8 rating. Although MERV 8 filters are on the lower end of common household air filters, that doesn’t mean they do a poor job. In many households, MERV 8 filters are a perfect choice.
Filtration Efficiency of MERV 8 Air Filters
Every type of air filter will have an average filtration efficiency built into the MERV rating. The filtration efficiency rating is the average percentage of contaminants that the filter will catch. So, if a filter had a 75% filtration efficiency rating for particles of 3 to 10 microns, it would generally catch about 75% of those contaminants.
MERV 8 filters have a filtration efficiency that’s solid but not the best. Usually, the larger contaminants in your air will be between 3 and 10 microns. On average, a MERV 8 air filter will successfully catch around 70% of those particles. So, approximately 30% of the larger particles will pass through the filter.
Certain types of contaminants are between 1 and 3 microns in size. A MERV 8 air filter will be able to trap up to 20% of them. Most of the smallest particles under 1 micron will be too small to be caught by a MERV 8 filter.
The small contaminant particles below 3 microns are where MERV 8 air filters have trouble. While they do a pretty good job of catching larger contaminants, filters with higher MERV ratings will do much better at trapping those that are smaller.
Which Contaminants Will a MERV 8 Air Filter Catch?
HVAC air filters with different MERV ratings can trap different types of contaminants. As I explained above, MERV 8 filters will mainly be effective at catching the larger airborne particles.
MERV 8 filters will catch a high percentage of:
- Dust mites
- Mold spores
These particles all tend to be larger than 3 microns, so a MERV 8 filter can trap most of them before they get cycled into your air. As for the pollutants smaller than 3 microns, a MERV 8 filter will only catch a relatively small percentage of them.
This includes contaminants like:
- Pet dander
- Certain kinds of bacteria
Some of these particles will get trapped in your MERV 8 air filter, but most of them will usually pass through. For this reason, people who have pets often choose filters with higher MERV ratings. The same goes for people who live in areas with significant amounts of smoke and pollution.
How Often Should MERV 8 Air Filters Be Replaced?
One of the keys to keeping your household healthy is regularly replacing your HVAC air filters. However, different filters have different guidelines for when you should change them. So, how often should you change MERV 8 air filters?
As a standard rule, you should replace MERV 8 air filters at least once every three months. But, there are also a few variables you should consider.
- Extreme weather – If you live somewhere very hot or cold, you may want to replace the air filters more often. If you’re running your air conditioner or heater all the time, the filters will catch more contaminants and get dirty quickly.
- If you have children – You should consider if there are small children in your home. In that case, you will probably want to make an effort to keep the air cleaner.
Remember; there’s no harm in replacing your MERV 8 air filters every one or two months instead of three.
Who Should Use MERV 8 Air Filters?
MERV 8 air filters are perfect for homes without the need for filtration.
- Homes without pets – If you do not have pets in your home, then air filters with MERV 8 would be a good choice.
- Homes without people with respiratory issues – If no one in your home suffers from allergies and asthma, go for air filters with MERV 13 rating.
- Homes safe from pollution and smoke exposure – You should also be fine with MERV 8 air filters if you do not live in areas exposed to smoke and other pollutants.
Air filters with a MERV 8 rating can clean the air in most normal circumstances. However, if your household has any special needs for air filtration, MERV 8 may not be enough. In that case, you will probably want to use more effective filters, such as MERV 11 or MERV 13.
MERV 13 Air Filters
Now, we will take a closer look at MERV 13 air filters. These filters are usually the highest-rated HVAC air filters found in residential homes. As you’ll see, filters with a MERV 13 rating are extremely effective at catching all airborne pollutants.
Filtration Efficiency of MERV 13 Air Filters
MERV 13 air filters have much higher filtration efficiency ratings than MERV 8 air filters. When it comes to the larger particles between 3 and 10 microns, MERV 13 filters will catch an impressive 90% on average. Only a tiny percentage of those contaminants will make it into the air you breathe. MERV 13 filters also do an excellent job of catching particles between 1 and 3 microns in size. On average, these filters will catch approximately 85% of those contaminants.
The area where MERV 13 air filters stand out is catching the smallest airborne contaminants. These high-quality filters generally catch around 50% of particles between 0.3 and 1 micron. This represents a huge difference compared to MERV 8 filters, which have trouble catching contaminants below 1 micron.
Generally, if your household HVAC system has MERV 13 air filters, there will be very few contaminants in your air.
Which Contaminants Will a MERV 13 Air Filter Catch?
For the most part, a MERV 13 air filter can catch all contaminants.
It will catch most larger contaminants, such as:
- dust mites, and,
- Mold spores.
It will also catch most smaller particles, like:
- pet dander,
- Smoke, and,
- Some larger kinds of bacteria.
MERV 13 filters will also catch many tinier viruses and germs. No matter what type of contaminants you have floating around the air in your home, there’s a good chance your MERV 13 air filters will trap them.
How Often Should MERV 13 Air Filters Be Replaced?
When replacing air filters, you must remember that filters with higher MERV ratings trap more contaminants. That means a MERV 13 air filter will usually get dirty much quicker than a MERV 8 filter. So, you won’t want to wait three months to replace your MERV 13 filters. Instead, you should make a point to switch out these filters every month. If possible, make it a routine to replace them on the same day every month. That way, it should be much easier to remember consistently.
Also, waiting too long to replace your HVAC air filters can be risky for your HVAC system. Clogged filters restrict the system’s airflow, leading to poor energy efficiency, worsened home comfort, and appliance breakdowns or malfunctions.
Since MERV 13 air filters are so effective at trapping contaminants, you must replace them regularly.
Who Should Use MERV 13 Air Filters?
Ultimately, MERV 13 air filters will work well for any household situation. However, only certain residential homes should need such effective filters. But in general, MERV 13 air filters are an excellent choice for homes with a need for intense filtration.
- Homes with multiple pets – If you have multiple pets in your home, you should go for air filters with MERV 13 rating. It would help clear out dander from your indoor air.
- Homes people with respiratory issues – Air filters with MERV 13 rating will be the best choice for you if you have anyone in your home suffering seriously from allergies and asthma.
- Homes exposed to pollution – If your home is exposed to pollution, you should use air filters with MERV 13 rating.
Because they are so effective, filters with MERV 13 ratings are also used in places like surgical facilities, pharmacies, and certain types of commercial buildings. They are also found in many other places that have extreme filtration needs.
How Should You Decide between MERV 8 and MERV 13 Air Filters?
For the most part, deciding between MERV 8 and MERV 13 air filters shouldn’t be too difficult.
All you need to do is consider the needs of your home and your family. Even if MERV 8 filters would do a solid job for your home, you may still want to keep the air as clean as possible. You may not need MERV 13 air filters, but you can still use them if that’s your preference, provided they are compatible with your HVAC system.
It’s also worth thinking about where your home is located. Do you live out in the country or in an area with many healthy trees? If so, there probably isn’t much pollution in the air. But if you live downtown in a big city, you may need higher-rated air filters to keep all that smog out of your air.
Remember: Don’t forget that there are professionals who can help you make these decisions. If you contact your local indoor air quality specialists, they can give you great advice on controlling the air quality of your home. They should be able to inspect your home, advise you on which filters you need and provide you with other helpful products.
Question: What does a MERV 13 filter out?
Answer: A filter’s Minimum Efficiency Reporting Values (MERV) indicate its ability to capture particles. Filters rated MERV-13 or higher can trap smaller particles such as viruses.
Question: Do you have to use HVAC air filters?
Answer: If you want to keep your air clean and your HVAC system healthy, you should always use air filters. Otherwise, your heating and cooling systems will become dirty and lose efficiency. Plus, there’s a good chance that you and your family will experience various health issues and discomforts.
Question: How often should MERV 13 filters be changed?
Answer: I recommend changing your Merv 8, 11, and 13 filters at least every 3 months, but changing your filter every 2 months provides better filtration, resulting in healthier and cleaner air in your home.
Question: Does MERV 8 filter smoke?
Answer: A MERV 8 filter only captures about 20% of particles smaller than 0.3 microns. Pet dander, smoke, and airborne bacteria will likely pass through a MERV 8 filter. Yes, it can capture smoke, but only 20%.
Question: Are air filters with higher MERV ratings more energy-efficient?
Answer: Usually, the answer is no. The opposite is usually true. Air filters provide resistance to the air as it flows through, and filters with higher MERV ratings create more resistance. The more resistance there is, the harder the HVAC system has to work to continue circulating air.
So, air filters with higher MERV ratings are usually less efficient than those with lower ones. That means that with MERV 13 air filters, your monthly energy bills may be more expensive than with MERV 8 filters.
Question: Do you have to pay more for higher MERV ratings?
Answer: Yes. Typically, the price of an air filter will depend mainly on its MERV rating. On average, MERV 16 air filters will be the most expensive, while MERV 1 air filters will be the cheapest. So, that means that MERV 13 air filters will almost always cost more than MERV 8 air filters.