The CAL16 and CAL 20 MERV 16 filters were mainly designed for California but would work just as well in other states where frequent wildfires are a concern. It includes a carbon layer that helps with absorbing VOCs, plus it offers the highest efficiency we have tested at the 0.4–0.7 micrometer particle size range (extremely important during a wildfire).

On top of that, it provides both a high loading capacity (about four times the capacity of most furnace filters) and a low resistance/pressure drop (nearly half the pressure drop of most furnace filters). It’s a beast of a filter! The only issue with this filter is that due to its massive size (five times the thickness of most filters), it requires a very specific filter housing, and installing that housing isn’t a DYI project. You’ll need to hire a pro to modify your return duct to be compatible with this filter, which can cost anywhere between $600-$1,200.

This filter costs about $100, which is considered high for an HVAC filter; however, in the long run, it provides better ROI due to its low resistance and higher loading capacity.