Filtrete 12x12x1 AC Furnace Air Filter, MERV 13, MPR 1900, Premium Allergen, Bacteria & Virus Filter, 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter, 2-Pack (Actual Size 11.81x11.81x0.78 in)

I use these as a cheap emergency replacement for HEPA filters: when stacked in series two of these 1" filters reduce the 0.3 micron particles 50-fold (98% arrest, verified with a calibrated particle counter). The 12" size is relatively standard , and fits into standard housings. These Filtretes are odour-free, unlike costly HEPA filters from certain supplies (e.g. IQAir). Now, I wish they costed less (hence 4 stars).

good hvac air filter

Good

Works well. Arrived undamaged. Well worth the extra money for quality.

Didn't fit like other 14x25x1. Was a bit longer so I had to rip the the bottom side a bit and force it to fit. We'll how it turns out once I need to replace.