HomeHoneywell Merve 11 Filter Furnace filters should be changed every 30 to 90 days. 20" x 25"x4" MERV 11Nominal Size: 20" x 25" x 4-3/8" Actual Size: 19-7/8" x 24-3/4” x 4- 3/8” Honeywell - 16x25x4 - Merv 11 C$54.95 Regular PriceC$52.95Sale PriceQuantityAdd to Cart