21 1/2x23 1/2x1 Aerostar Air Filter

At an actual 21 1/2" x 23 1/2" x 3/4", the 21 1/2 x 23 1/2 x 1 Aerostar fits a custom-spec nominal opening common in certain regional HVAC markets. MERV 8 covers standard household filtration: dust, lint, pollen. MERV 11 handles pet households and most common allergens. MERV 13 captures fine particulates including bacteria, virus-carrying droplets, and wildfire smoke - the grade to choose for households with respiratory health issues. Pleated synthetic media with an electrostatic charge built into the fibers handles the actual filtration work. The pleats provide substantially more surface area than a flat fiberglass filter at the same nominal size, which extends the service life to 60 to 90 days under typical residential conditions. The electrostatic charge improves capture of sub-micron particles where mechanical filtration alone reaches its physical limits. Manufactured by Con-Air Industries in Orlando, Florida. Cardboard frame, reinforced to maintain shape under blower suction. Custom-spec filters benefit from precise dimensional matching - a filter that's even slightly off-spec leaves a gap where unfiltered air bypasses the media entirely. This filter is built to the specification without modification, which is the only way higher MERV grades actually deliver the filtration improvement they promise.