Review on Flanders Precisionaire 20x20x1 Case (Nested) - Product #2488665 by Knate Scarpelli

Superb pre-filter for my hybrid heat pump with integrated HEPA filter. This filter makes HEPA much cleaner and my HVAC specialist recommends this high capacity, high porosity pre-filter. This bulk purchase greatly reduced my costs, as did the time it took me to find that somewhat outdated 21 x 21 x 1 inch. It's not really intended to be the primary single filter for your system. IMHO. It only catches larger particles, insects, etc. e. Swapping every 4-5 weeks in a household with no pets and no children is fine with us.