What Happens When an Air Filter is Too Thick?

An incorrect air filter can reduce HVAC efficiency and increase heating and cooling costs. Learn what happens when an air filter is too thick and how to avoid pitfalls.

What Happens When an Air Filter is Too Thick?

An incorrect air filter can reduce HVAC efficiency and increase heating and cooling costs. If the filter is too dense, the heater or air conditioner may have to run longer to counteract increased air resistance. Thick air filters may seem like the best option, as they have more square meters to capture and retain air particles. However, folding the filter makes the seal imperfect, allowing dirt and debris to accumulate on the fan, slowing down airflow, degrading performance, and lowering air quality.

Using an incorrectly sized air filter won't necessarily damage your HVAC system, but it does have an impact. It reduces the efficiency of your heating and cooling system, which can add up quickly and become an apparent problem that you're likely to notice on your next utility bill. Coarser filters provide a better fit that does not allow unfiltered air to pass through. Some air conditioning specialists have also noticed that coarser filters provide a better fit that does not allow unfiltered air to pass through.

This means that it is less restrictive to airflow, which helps the HVAC system operate more efficiently. So you will not only clean the air better, but you will get much more airflow than standard one-inch ones. In fact, researchers have found that while high-MERV filters can create a pressure drop, the impact is not significant unless the filter is laden with dirt. Virtually any HVAC professional will tell you that coarser filters work better than ordinary 1-inch oven filters.

If you want to use pleated filters and superior MERV filters, the only sure way to do that is to have a 5- to 6-inch media filter installed by a professional. Some HVAC units cannot push air through HEPA filters and others with a high MERV, so be sure to follow the manufacturer's recommendations to avoid affecting system efficiency. MERV 9-12 are usually the highest quality air filters you'll find in normal residential buildings. Another consequence of low airflow is that the air conditioner coil may become too cold and even freeze. It is better to use filters with wide pleats and ensure that the ventilation grilles are free of any material that could block air flow. Yes, using a merv13 pleated air conditioning filter as part of a mask is possible.

It seems that it would be enough to just use the high merv filter media, blast it with compressed air, and then insert the filter into a pocket of the DIY face mask, between the two layers of fabric. An electrostatic air filter is a filter that has been charged with static electricity, trapping small particles such as mold and bacteria and holding them in place.