17.5x21x1 ACTUAL: The actual size of this replacement filter is 17.5" x 21" x 0.75" MERV 8 RATING: With an efficiency of 70% to 85%, these filters are usually the best option for most residential homes & light commercial units, ensuring airflow in your HVAC system is unrestricted. CAPTURES PARTICLES: Breathe easier in your home as our filter clears the air of dust, lint, and other indoor impurities. AFFORDABLE QUALITY: SpiroPure air filters are sold in packs to save you even more without cutting corners on material quality, efficiency, or filtration performance. QUALITY REPLACEMENT: Comparable to a 3M Filtrete MPR rating of 1000-1200 (Allergen Defense and Dual-Action Micro Allergen Dust Defense models).

Find a value pack of high quality replacement MERV 8 furnace filters from SpiroPure. SpiroPure pleated AC & Furnace filters are made in the USA and are the perfect choice for most standard residential and light commercial air conditioner and furnace units. Please measure your existing air filter before ordering to ensure that this size will be compatible with your AC & furnace system.

We recommend replacing your furnace filter every 3 to 4 months for maximum efficiency and cooling and heating system life.