Hepa filters put a huge strain on a blower as the pores are so small,
never do this one without an experts advice on capacity.


If the filter is, say, 3" thick and had many, many pleats then the extra
area can compensate for the extra resistance of the HEPA filter medium.

To me, that's the way to go. Rather than a high maintenance electrostatic
filter which, typically, requires 6" of space in the direction of flow, get
a pleated HEPA filter that fits in the same space.



The issue with HEPA filters that the poster complained about is that in
order to get the 99.97% entrapment of 0.3 micron particles and larger
takes large amount of fan power. Furnace fans cannot do this by
themselves. To move 1500 CFM (typical flow number for 4 ton AC units)
through a typical HEPA filter requires almost 1HP of fan power. Air
handler fans are woefully inadequate to this task as a typical air
handler fan only has a tiny budget left for filter resistance.i.e. MERV7
OVERLOADS THE FAN!!!

Shouldn't you be able counteract this by increasing the area of the
filter?