Would a HEPA furnace filter help with a mold problem?
A HEPA (High Efficiency Particulate Air) filter is unlikely to make much difference. In the first place, a one-inch medium efficiency pleated paper filter has adequate filtering capability for the majority of homes. It can replace typical throwaway furnace filters with no required modifications to the ducting. A HEPA filter can more effectively trap finer particles than a medium efficiency filter, but it is more than what is needed in most homes where pets, carpets and other sources of particulates may still be present. To install a HEPA filter, the cold air plenum would need to be modified to accommodate the thickness of the HEPA filter. Because of the increased resistance to air flow, the blower would also have to be upgraded. Lastly, A HEPA filter cannot be replaced as frequently as the pleated paper filters because of the higher cost. It can end up accumulating a lot more dirt than a less efficient filter before it gets replaced.
