Camfil 24x24x4 Furnace Filter Merv 11. (6-pack) MERV 11: High Efficiency - State of the art filtration capabilities remove allergens, the perfect choice for Canadian homeowners to elevate air quality. Brand name reliability at a low cost: pay only $38 per furnace filter! Most popular option for... MSRP: Was: $286.00 Now: $228.00 Add to Cart