Hvac Air Filter Cfm Rating

Flow rate equals area times velocity.

Hvac air filter cfm rating. Hvac air filters with a merv rating between 13 and 16 capture particulate matter between 30 and 1. Ashrae developed the merv air filter efficiency rating system. 400 fpm select disposable or reusable media. Type ii pleated panel filters 1.

A standard merv 7 16x25x1 pleated filter is rated for 0 2 iwc pressure drop at 300 feet per minute fpm. Hvac air filters with merv 9 to 12 capture at least. The rating system is called ashrae standard 52 2 2007. Style nominal filter size inches w x h x d 2 filters ring and link.

It s also fairly common to find this filter installed on a three ton air conditioning system. As you can see there s not a steady increase in pressure drop as the merv rating increases. Select air filter dimensions length width thickness. That converts to 835 cfm of airflow for rating purposes.

Bypass air is used in some heat pump systems to control system performance and economy by sending some air around rather than through the cooling or evaporator coil. Legionella pneumonia humidifier dust mineral dust flour. Hvac air filters with a merv rating between nine and 12 capture particulate matter between 1 0 and 3 0 microns. Calculate airflow velocity in linear ft min.

See my article on the continuity equation for more on this results. What does happen though is that the. As air moves through a building s hvac system air filters trap and collect large and small particles such as dust allergens and microorganisms. This method tests air cleaning devices for dust removal efficiency.

If your home has a very old hvac system or you use a higher merv filter and never change it you could run into airflow problems but under normal circumstances you won t be stressing out your hvac system that much with a higher merv filter. We test airflow resistance which measures how freely air flows through the filter. With that face velocity and those dimensions the air flow rate is 1 367 cubic feet per minute cfm. Many thermal design engineers use the following steps when designing an air filter.

Three ply panel filter with internal wire frame 24x24 air flow capacity cfm 1968 filter face air velocity fpm 492 maximum initial resistance inches w g 0 40 minimum rated final resistance inches w g 1 0 minimum merv rating 8 b. Consumer reports tests air filters for homes with forced air heating and cooling systems. Notes to the table above. Hvac equipment operated at higher air speeds than those for which it was designed loses efficiency and for filters will begin to bypass rather than remove particles from building air.

According to the american society of heating refrigerating and air conditioning engineers ashrae this filtration helps provide healthier indoor air quality a filter s merv number indicates how it s rated to remove these particles. Ashrae stands for the american society of heating refrigerating and air conditioning engineers.