What are the Differences Between Pre, Mid and HEPA Air Filters?

First, different functions.

Pre filter: Mainly used for filtering dust particles above 5μm, suitable for the Pre filter of air conditioning system;

Mid filter: belongs to F series of air filter, generally bag filter, including F5, F6, F7, F8, F9 grade. Intermediate filter is widely used in air conditioning system, mainly 1 for filtering more than 1-5um dust particles;

HEPA filter: mainly used to catch particulate dust and various suspended matter, less than 0.5um.

Second, different materials.

Pre filter: Outer frame material including paper frame. Aluminium frame. Galvanized iron frame, filter material including non - woven fabric. Nylon mesh. Activated carbon filter material. Metal hole mesh;

Mid filter: bag type, frame type, combined type, etc.;

HEPA filter: Using ultrafine glass fiber paper as filter material, offset paper. Aluminum film and other materials as a partition plate, and wood frame aluminum alloy bonded.

Third, different filtering accuracy and speed.

Pre filter: G1 ~ G4  5 micron  65%, 80%, 90%, 95%;

Mid filter: F5 ~ F9  1 micron  60%, 70%, 80%, 90%, 95%;

HEPA filter: H10 ~ H14  0.5 micron 95%, 99.5%, 99.95%, 99.995%, 99.9995%