How Often Should You Change Your Merv 11 Filter?

Learn how often should you change your Merv 11 Filter for optimal filtration and healthier air in your home.

How Often Should You Change Your Merv 11 Filter?

For Merv 8, 11 and 13 filters, it is recommended that you change the filter at least every 3 months for optimal filtration and healthier air in your home. However, if the filter is made of fiberglass, experts suggest changing it every 30 days. Pleated filters can last up to three or six months before needing to be replaced. If you are unsure of the filter change frequency of your oven, you can perform a visual check to see if you have an old filter or a newer one.

If there is only a thin layer of dirt where you can still see the filter underneath, then you probably don't have to change the filter. However, if there is a thick layer of dirt in which you can't see the filter underneath, it's time to change it. We recommend that you perform a quick visual check of the filter every 3 or 4 weeks if you are unsure of the frequency of replacement of the oven filter. There are many common filter sizes, so make sure you get an exact measurement of your furnace filter type.

If you feel a pressure drop in your home or notice a difference in the performance of your heating and cooling system, the dirt filter is usually the first place to look. You must change the filter at least every 90 days. A general rule of thumb for pleated air filters (such as those manufactured by FilterBuy) is to replace the filter every 90 days. As the filter traps more dirt, dust and allergens from the air, its efficiency decreases.

If you have pets in the household, you should consider changing the filter every 60 days or 2 months, and for households with multiple pets or people with allergies or respiratory conditions, we recommend changing the filter every 20-45 days. Usually, vacation homes or empty homes that don't see much use can wait to change filters every 9 to 12 months. The general consensus is that the more you use your home, the more you need to change the air filter. If you have poor air quality outside or pets indoors, you'll need to replace your air filter more often.

For smaller appliances used to cool small spaces, it often comes with smaller filters, so you may have to change the filter as often as a filter in a larger house. If there is a visible layer of dirt covering most of the filter surface and that is thick enough to hide the filter material itself, it is a sign that the filter has been in the HVAC system too long. As mentioned above, the presence of pets, young children and people with allergies will require you to change the air filter more often. If you live in a “smaller” house, your air conditioners and ovens must pump less air for the same amount of temperature change, which could mean fewer filter changes.

Northern inhabitants whose ovens have no rest for months may want to change their filter every 30 to 60 days because more air is sucked through the filter and it will become clogged more quickly. Due to their pleats, filters such as Honeywell Ultra Efficiency filters have more square inches of space to trap dust and usually require fewer changes - usually every 90 days. It is important to remember that all air that circulates through your HVAC system will eventually pass through an air filter. Clogged filters not only adversely affect air quality in a house but also force an oven to work harder which can shorten its life span.

You can hear it now: Your HVAC technician is giving you lessons on how to make sure you change your air filter.