Question: what are best furnace filters?
Answer: AIRx Health 1" MERV 13 Furnace Filters. ...  Honeywell FC100A1037 Ultra Efficiency 4" Furnace Filters. ...  Nordic Pure 4" Furnace Filters. ...  FilterBuy 1" Furnace Filters. ...  AIRx ALLERGY 1" Furnace Filters. ...  Filtrete Micro Allergen 4" Furnace Filters. ...  X6673 Lennox 4" Furnace Filters.