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Making Sense of What Air Filter to Use

You hear terms like MERV, HEPA and more when it comes to air filters but what do they all mean? It can get a bit confusing. In this post we hope to clear up some of the confusion out there and guide you to what air filter is best in some of the more common locations.

First let’s look at the types of filters. The two most common are HEPA, which stands for High-Efficiency Particle Air filter. Sounds fancy. Basically a HEPA filter is the top of the line. It is going to capture the most particles and the “bad” things in the air. Next is MERV, which stands for Minimum Efficiency Reporting Values. MERV filters will also have a number after them like 8, 11, 13, 16 and so on. The number is the key component, as this will tell you how effective the air filter is in capturing particles. The higher the number the more it will capture.

At first glance most people would say it is an easy decision to just use the best, highest rated filter for everything. Unfortunately it isn’t that easy. Air filters are a balance of working efficiently and capturing contaminates. What happens is that the higher the efficiency of the air filter, the more restrictive the airflow through the filter.

That brings us to the main point of this post – what air filter to use. This is a little bit of a trick question. The answer is it depends on the situation. Let’s take a look at the more common areas of the home that benefit from air filters.

HVAC System: This is a key component of the home and one you definitely want to get the air filters correct in. The HVAC system is going to provide air to the entire home so it makes sense that we want it to be the best it can be. As we stated earlier the temptation is to utilize HEPA filters then sit back and enjoy all that high quality air floating through the home. Sounds great but most current HVAC systems cannot handle HEPA filters. The filters constrict the airflow and can actually cause damage to the system or reduce the life of the system. We are hopeful that as technology advances so will the filtration systems. So what do we do? Enter in MERV. Most systems can handle up to a MERV 11 filter. While not a HEPA filter it still provides high quality filtration and will remove items like Pollen, Mold, Dust, Pet Dander, and Debris. What are missing from this list are items such as viruses, bacteria and allergens. To filter these out you need to move up to a MERV 13 or higher. You should always consult your HVAC professional to see what the highest rated filter your systems can handle is.

Portable Air Filtering Devises: If the HVAC system is unable to remove some of the more hazardous items or you don’t have a central system, we need to turn to other methods. Room level units are a good alternative. Here is where we go for the gold and you should look for a unit that is using a HEPA filter. There are a lot of these units on the market and they have varied effectiveness. You will also see units with added items like UV, IONs and so forth. The jury is still out a bit on the added technology so our recommendation is to focus on the HEPA air filter aspect of the unit. The downside to these units is they typically can only filter small areas (might need one for each room you use) and the filters can get a bit expensive to replace.

Air Intake Units: Many home, especially newer homes are required to have what is referred to as a fresh air intake system. This is typically a fan that brings outdoor air into the home to replace the air being exhausted out the home. While in most cases an air filter is not mandatory, it can make a very positive impact if it is used. This is also a case where your specific situation will dictate what filter should be used. We have already talked about a HEPA filter but here again we are faced with a HEPA filter restricting the airflow to a point where it may render the unit ineffective. That leads to using a MERV filter, but which one? In general outdoor air can be up to 5 times less polluted than indoor air. This is important because it means the air coming in doesn’t necessarily need to be filtered as much as the air inside the home. One big thing is generally you will not be bringing in viruses from the outdoor air. Most times you only need to be concerned with items like pollen, dust, particles and so forth. A MERV 11 or higher will be fine for that. Now if you live in an area that has high levels of pollution like in or close to a large city or in areas of the country that have wildfires, you might want to consider a MERV 16. MERV 16 filters are able to remove items like smoke, smog and even viruses.

So how do we bring this all together? At the root of this is improving indoor air quality. To do this takes a group effort. Just having good filters in your HVAC system won’t be enough just like having only a portable air filter won’t do it either. Developing a strategy is key. Having a proper ventilation system (bad air out) while bringing in filtered outdoor air will greatly improve the indoor air quality. Now add the highest rated filters you can to your HVAC system as well as a portable air filter and you’re onto something. Air King has developed what we refer to as the Total Home Ventilation system that utilizes air intake and exhaust to create a better living environment. To learn more about the system click here. Also make sure to view portable solutions from our Germ Guardian division.

For more information about the indoor air quality of your home and how you can improve it, please read through the many articles we have written over the years. For information regarding Air King exhaust fan and fresh air intake solutions click on the links in the menu at the top of the page.

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