Lysol Unscented, 1″ Replacement Furnace Filters, Certified Allergy and Asthma Friendly air filters. The Lysol brand is expanding their product line and now offers furnace filters to the market! The Lysol 1″ Furnace Filters have a MERV 12 rating and are certified asthma and allergy friendly! With this MERV rating, it makes Lysol one of the best 1″ filters on the market for consumers with allergies or asthma. The filter will trap and permanently remove pollen, dust, dust mites, mold, some bacteria, odors, and many other allergens/pollutants. The Lysol 1″ air filters should be replaced every 3 – 4 months to ensure optimal performance.