Furnace Filter Airflow Resistance

It removes more contaminants from the air but it means that your furnace or air conditioner has to work harder to push the air through your home.

Furnace filter airflow resistance.

If your filter is either too dirty or too resistant it can cause airflow problems hurting the efficiency and performance. Likewise the mid merv filters also showed decreased air flow relative to the low merv filters this time 3 and 8 lower in the two systems. Merv rating is essential for finding the proper furnace filter for your home. Merv filter ratings and air quality.

Remove the existing furnace filter which will be located inside the furnace or inside the return air vent. As the filter loads up with the stuff it catches the resistance increases. They also found that air flow in the high merv filters dropped by 7 and 11 in the two hvac systems compared to the low merv filters. To determine resistance filters use the merv rating system.

A higher merv rating means the filter is more restrictive. Using a filter with a higher merv rating could mean that your hvac system runs longer than it would with a filter with a lower merv rating. The smaller pores in more highly rated air filters create resistance to air flow and if the filter is used in an hvac system that is not designed to handle this resistance it can lower the system s efficiency decrease indoor air quality and put strain on the system s fan. The standard fiberglass filter doesn t resist the air flow much at least not when the filter is clean.

Dust holding capacity defines the amount of dust an air filter can hold when it operates at a specified airflow rate to some maximum resistance value. In short the higher the merv rating is the more resistant the filter is. If you re really interested in keeping your air clean we d suggest you get an air cleaner purifier installed in your air ducts. How much resistance depends on the type of filter material and the amount of area.

Our test duct is 8 feet long two feet wide and two feet high. Start by turning off the furnace. If your unit is older and or very sensitive with airflow use a filter that ranks from merv 1 up to possibly merv 6. Going through the filter material the air encounters resistance.

To build some good comparative data we tested 20 different air filters of various types thicknesses and efficiencies. Look for an arrow on the filter indicating airflow. The jist of the myth is that these filters are the only ones that have a low enough resistance to allow sufficient airflow for the system to operate adequately. Air cleaners which have a thick media filter can trap small particles like pet dander and mold without impeding air flow like a thin pleated air filter would.