By definition, true HEPA filters are at least 99.97% efficient at filtering 0.3 μm mass median diameter (MMD) particles in standard tests.
Most penetrating particle size may be smaller than 0.3 μm, so filtration efficiency of most penetrating particles can be slightly lower.
HEPA filter efficiency is better than MERV 16.
HEPA filters may not be an appropriate option for some HVAC systems due to high pressure drops and the likelihood that systems will need new filter racks to allow sufficient sealing to prevent filter bypass from occurring.
To function properly, HEPA filters must be sealed properly in filter racks.
HEPA filters are often delicate and require careful handling to prevent damage and preserve performance.
HEPA filters can be located in HVAC systems or in:
