18x20x1 MERV 2 Non Pleated Air Filter Replacement Filters (Actual Size 17.75 x 19.75) - 3 Pack Aluminum even without needing to remove

even without needing to remove the thermostat

+ Product Details Size – Stick-on collar is 12" and it is compatible with duct 12"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 16" x 22" OR 22" X 16" duct opening (measured at the opening)

actual front end outer dimensions are 15

18x20x1 MERV 2 Non Pleated Air Filter Replacement Filters (Actual Size 17.75 x 19.75) - 3 Pack Aluminum even without needing to remove+ Product Details 18" x 20" x 1" replacement air filters for your furnace, air conditioner, heat pump, or HVAC system (actual size: 17. 75" x 19. 75") A unique combination of cotton & synthetic fibers gives you the most filtration and the least air resistance equals great air & easy airflow for your system. The non pleated design provides low airflow resistance while still effectively capturing dirt and particles such as standing dust, spray paint