Should You Use a Washable or Disposable HVAC Filter?

As the population moves to become more green, they want to see more products that are washable and reusable, and will stop them from adding to the landfill. This push begs the question, “What is better, washable filters or disposable ones?” You might be surprised by the answer.

MERV

MERV is an acronym that means Minimum Efficiency Reporting Value. It was made by the American Society of Heating and Refrigeration Engineers to quantify the quality of air filters. If you have a higher MERV rating, then the better that filter is at gathering microscopic airborne particles.

To start, it matters that we understand what MERV is, and the way it will change your filter purchase. Your usual washable filter has a MERV rating of around 4. At its worst, a filter with a MERV rating of 4 will gather the larger-sized particles.

The MERV score is also dependent upon the efficiency of a percentage basis. It’s important to remember that the more a filter will collect dirt, the quicker it will become dirty, which in turn will drop its efficiency, save frequent cleanings. A MERV 4 rated filter is going to collect pet hair but not pet dander.

When you’re allergic to pet dander (not asking why you have a pet), you might need a filter with a higher MERV. This will serve to better collect the smaller particles.

Cleaning

When you have a washable filter that has a MERV of 4, and you clean it often, it will always collect the pet hair, but most likely not the dead skin cells and pet dander. Say you’re allergic to pollen and house dust as well, a MERV 4 filter will not filter as well as one with a higher rating. But if you wash a filter that’s reusable, you are going to need to wait until it is totally dry before you put back in the system or it will mold. This means you either need your HVAC unit off, or you have two filters.

Consider the coils

Another thing to remember is that your filter that’s attached to the return air grill will be sucked into your coils. Thus, a high MERV rating will gather lots of particulates but can also make it more difficult for the unit to pull, which means your electric bill will go up. A lower MERV is best for air flow, but you might wind up having dirty air and dirty coils. Because dirty coils are so expensive to clean, you should never run your HVAC unit without a filter.

The magic number

A lot of people discover that their filter with a MERV rating of 11 does an amazing job to keep the air clean, but will choose to go down to a MERV rating of 8 to propagate more air flow, and a lower electric bill. Sometimes the highest MERV rating can cause problems with some units, so it is better to look at the owner’s manual before changing which MERV rating you want to go with. If questions should arise about which air filter is right for your system, you should call us or ask one of our professional technicians at your next scheduled service. We’d be happy to hear from you.

For comparison sake, here are some sizes:

Human hair: 60-100 microns

Pollen: 30 microns

Household dust: 10 microns

Pet dander: 5 microns

Bacteria: 1-10 microns

Covid: 0.125 microns

Wavelength of infrared radiation particle: .70-300 microns

Forecast Heating, Cooling, and Refrigeration serves residential and commercial customers in Summerlin, Anthem, North Las Vegas, Boulder City and Las Vegas. Call us at 702-919-4546.