Skip to Content

Blogs from November, 2019


It’s almost impossible to understate the importance of your air filter when it comes to your heating and cooling system. Everything from major breakdowns to routine issues alike can be traced back at least partially to a clogged air filter slowing your system down and preventing it from operating smoothly. That’s why replacing your air filter regularly is so vital to preserving your system and why you need to make sure the air filter you’re using is the right choice for your needs.

All of the air that is forced through your HVAC system starts in your return register and is pulled through your air filter before going into your air handler or heat exchanger and then out through your air ducts. As air filters strain debris from the air that passes through them, they become clogged and allow less and less air to pass through. When less air can pass through your filter and into your HVAC system, HVAC system becomes less efficient and even sustains additional wear and tear from having to work harder to keep your home comfortable.

In this blog, we’ll go over what you need to know about your air filter and offer you some helpful DIY tips on how to choose the right air filter for your heating and cooling system’s needs.

How Are Air Filters Different?

Sorting through the world of air filters can be an intimidating thought. What should you be looking for? What do the various numbers mean? Is there such a thing as the “right” filter for your needs? What should I look out for? What things should I be avoiding? To the average person, these are all valid questions and they’re something we want to help you with. Here’s a brief crash course in understanding what air filters are and what the various numbers and measurements mean.


Air filter sizes are usually given in three numbers, and the system is both simple and logical. The numbers are length, width, and thickness, usually given in the form of AAxBBxCC. If your air filter uses a filter that’s 24 inches long, 16 inches tall, and one inch thick, then the filter will be labeled as 24x16x1. The length and width of your filter should remain constant throughout the life of your HVAC system and may not even change from system to system. However, the thickness of your filter may change based on a few different factors that we’ll discuss shortly.

MERV Rating

The next thing you need to know about air filters is how much a particular filter actually filters the air that passes through it. This is determined by a filter’s MERV rating. MERV stands for “Minimum Efficiency Reporting Value,” and essentially measures how much your air filter blocks in comparison to peak efficiency value. The more air is blocked, the more a filter actually strains out, and thus the higher the MERV rating. Therefore, higher MERV ratings are more effective at removing debris from the air. However, as we’ll see in a moment, that isn’t always the best

What Air Filter is Right for You?

So how do you choose the right air filter for your home? Let’s start with sizing. As we said previously, the length and width of your filter should not change. Check with your owner’s manual to see what size filter they recommend and make sure you’re matching the length and width dimensions for optimal fit. The manufacturer’s recommendation for thickness is also a good place to start, but there may be some wiggle room there. If you find that you’re struggling with air quality, a slightly thicker air filter may be a solution. For example, if you’re struggling with poor air quality and using a one-inch filter, but your system can support up to 2 inches, then swapping over to a two-inch filter may be the key.

Then there’s the issue of MERV rating. Let’s just get this out of the way up front: more is not always better when it comes to MERV ratings. Sure, a 24 or 26 MERV filter may sound great—who wouldn’t want surgery-room-quality air in their home if they struggle with indoor air issues. There are a few downsides to this: first, the filters themselves are tremendously expensive. The higher your MERV rating, the more costly your filter is going to be. Second, your system may not be able to work with a MERV rating that’s too high. When you increase the MERV rating, your system has to work harder to pull air through, and that means more energy burned and more wear and tear.

Consult your owner’s manual and see what your manufacturer recommends for MERV ratings. If you feel as though you need some extra filtration, talk to a professional and see what they recommend for improving your indoor air quality before increasing your MERV rating any further.

If you’re struggling with poor indoor air quality, call Moe Plumbing, Inc. at (818) 396-8002 and let our experienced professionals help!