On the amazing Project Farm
, Todd wonders
what the real performance characteristics and differences are between cheap furnace filters and the expensive ones. As always, he creates testing rigs and puts a whole pile of filters, from $1 to $50, to the test.
Tl;Dr: So which one won? It’s complicated. The thicker filters (2″ and 4″) performed better than the common 1″ filter size, but your furnace may not accommodate a larger size. The permanent, washable filter did not perform well. Nor did the cheap ones. Looks like you want to get the thickest filter your furnace will accommodate and one with the most pleats in the outer filter. Overall, 3M brand filters did really well, like the 600
, and the 1900
. (Obviously, you need to get the filter that is the correct dimensions for your furnace.)