K N 18X20X1 Hvac Furnace Air Filter, Lasts A Lifetime, Washable, Merv 8,, 11820 Since 1969, K N has been inventing and manufacturing creative air filtration solutions for the automotive market. Now that expertise has been brought into the home, with K N?s new washable, reusable HVAC air filter. Made from a pleated synthetic filter media, K N lifetime washable home air filters provide excellent filtration for long-life performance. Instead of repeatedly purchasing new disposable filters, simply wash and reinstall your K N filter whenever it is dirty. Save money, help the environment, and protect your family with K N! The LAST AIR FILTER YOU WILL EVER BUY: Washable furnace filter for long-term home HVAC filter savings SAVE MONEY: Save $30 annually with reusable air filter compared to disposable, one time use filters INCREASE HVAC EFFICIENCY: Excellent airflow to help maintain HVAC system efficiency GUARANTEED QUALITY: Premium design and construction for excellent air filtration DIRECT REPLACEMENT: Designed to fit directly into your filter register