The FILTER Dilemma

My House is Dusty – What filter will remove it?

Here is the bad news!

Even the best of filters will only remove the dust that gets to the filter. Most dust particles are heavy enough that they fall to the floor or other surfaces before they reach the filter.

Bear with me as I take you through the dust process. I promise you will have more clarity.  😊
When your cooling or heating system is running it is moving air to the return grille and sending it back to the supply grilles. During that process the air moves through the filter. At this point your filter will stop some airborne particles. The better the filter = smaller particles it will stop and collect.

If you have ever looked at a ray of sun coming through a window you have witnessed seeing particles in the air. If you were to shake out a throw rug in that ray of sun you would actually see larger particles floating.

Some of those airborne particles stay suspended in the air and will move to your filter when the system is running. Additionally, these small particles can actually cling to any larger particles that we stir up while using our home. Then they fall to the floor or other surfaces before they get to the filter because they are so heavy.

A great filter will capture the suspended particles and actually clean up your dust! I know, clean dust. I say this because you may actually see your dust better after it is cleaned up. I have had clients report that they have more dust now with a better filter.

There is good news! It is the smaller particles that have the greatest affect on our health and a good filter will help with that. The larger particles, and this is going to sound disgusting, are captured through our bodies defense system and we get rid of those by a variety of bodily means. I know-Yuck.

With air filters, there a lot of terms thrown around like MERV rating, Restriction, Pleated/Poly, HEPA, Healthy Filters and more that can create some confusion. 

The Big Box stores have great selections, but which one do you choose? I have my opinions which I am going to share with you as we look at the different types you can buy for your home…

What is MERV?

MERV stands for ‘Minimum Efficiency Reporting Value’, which basically means the higher the MERV rating, the smaller size particle the filter will capture. MERV is the industry standard for measuring filtration. MERV can range from 1 to 20.

STANDARD 1” Fiberglass Filter: Has a rating of about MERV 4. This is very commonly used but doesn’t provide much protection for your equipment. A lot of airborne particles get right through the filter and onto your blower fan and indoor AC coil. It has a very low restriction to airflow. You change these filters about every 3 months.

PLEATED 1” Media Filter: Has a rating of about MERV 8. A lot of folks use this type of filter. At the Box Stores you can find them in many sizes. Some advertise they help with allergies! These provide better protection for your equipment and capture a lot smaller airborne particles. These filters have a higher restriction to airflow and can cause operational issues if not changed frequently enough or if your system is already struggling to deliver airflow. You change these filters in 1 to 3 months.

PLEATED 4” to 6” Box Filter: Has a rating of MERV 8 all the way up to 16! These filters will generally last longer before needing replaced and because they have a larger surface area, they do not restrict the airflow as much as the 1” Pleated filter. They are also right at the indoor unit which can give maximum protection of your equipment. You change these filters every 6 to 12 months.

In general, the cheaper filters you’ll find at the hardware store max out around MERV 8 while the more expensive filters go up from there. MERV 16 and better filters are usually considered HEPA filters and you’ll find them in hospitals and clean rooms because they’re capable of catching smoke, bacteria, and viruses.

On the surface, it seems like you want to buy the highest MERV rated filters you can afford BUT that could cause problems with how your system operates. The higher MERV filter you use, the more restrictive it is on the air flow. You could freeze up your system because the filter is too restrictive. 

Think of it like using a coffee straw instead of the regular straw. You have to work harder to get the same amount of liquid through the smaller straw. Your system has to work harder to move air through the ducts when you use a filter that is very restrictive.

You need to find the perfect balance between airflow and air filtration on your system. A good company will check this when performing maintenance during a tune-up. They will test the static pressure on your system with a magnehelic gauge to measure the resistance to airflow and help you determine how much filtration your home can currently handle.

Asthma and allergy afflictions are at an all time high. If you spend a fair amount of time in your home and want to breathe cleaner air than your system is currently set up for, there are some great options to reduce the static pressure of your system, capture more of the particles in the air you breathe, and help to remove microbial growth, kill bacteria, and reduce or eliminate odors in your home.


Author: Bill Fortner

Company: Blue Label Services



About Blue Label Services:

Here at Blue Label Services, our customers have always been our highest priority. If you’re not happy, we’re not happy. We are 100% focused on your satisfaction and we take pride in providing exceptional service.

Whether you need a minor repair or a full installation, call us today for the service you deserve. We have over 40 years of experience in the air conditioning and heating industry, and there’s no issue our certified technicians can’t solve. Make an appointment with us today!



Phone: 832-968-8630

Categories: Air Conditioning.