{"product_id":"21-1-2x23-3-8x1-air-filter","title":"21 1\/2x23 3\/8x1 Aerostar Air Filter","description":"A 21 1\/2 x 23 3\/8 x 1 nominal return takes a filter sized at 21 1\/2\" x 23 3\/8\" x 3\/4\" actual, which this Aerostar matches exactly. Custom and semi-custom HVAC installations spec dimensions like this when the original return opening doesn't conform to a standard nominal size. MERV 8 covers baseline residential filtration: dust, pollen, lint. MERV 11 handles pet households and mild allergy concerns. MERV 13 captures fine particulates including bacteria, virus carriers, and wildfire smoke - the grade for households with respiratory health concerns. Pleated synthetic media with an electrostatic charge built into the fibers handles the filtration. The pleats provide substantially more surface area than a flat fiberglass filter would at the same nominal size, which is what extends the service life to 60 to 90 days under typical residential conditions. The electrostatic charge catches sub-micron particles where the physical weave alone reaches its limits. Manufactured in the USA by Con-Air Industries at the Orlando, Florida facility. Cardboard frame, reinforced to hold shape under blower suction. Odd-size filters benefit most from dimensional precision because an off-spec filter leaves gaps for unfiltered air to bypass the media, which undermines higher MERV grades.","brand":"Aerostar","offers":[{"title":"MERV 8 \/ 6","offer_id":41902214414490,"sku":"P80S.0121H23F-6","price":55.99,"currency_code":"USD","in_stock":true},{"title":"MERV 11 \/ 2","offer_id":41902214250650,"sku":"P15S.0121H23F-2","price":40.99,"currency_code":"USD","in_stock":true},{"title":"MERV 13 \/ 2","offer_id":41902214283418,"sku":"P25S.0121H23F-2","price":48.99,"currency_code":"USD","in_stock":true},{"title":"MERV 8 \/ 4","offer_id":41902214316186,"sku":"P80S.0121H23F-4","price":44.99,"currency_code":"USD","in_stock":true},{"title":"MERV 11 \/ 4","offer_id":41902214348954,"sku":"P15S.0121H23F-4","price":50.99,"currency_code":"USD","in_stock":true},{"title":"MERV 13 \/ 4","offer_id":41902214381722,"sku":"P25S.0121H23F-4","price":53.99,"currency_code":"USD","in_stock":true},{"title":"MERV 8 \/ 2","offer_id":41902214217882,"sku":"P80S.0121H23F-2","price":30.99,"currency_code":"USD","in_stock":true},{"title":"MERV 11 \/ 6","offer_id":41902214447258,"sku":"P15S.0121H23F-6","price":72.99,"currency_code":"USD","in_stock":true},{"title":"MERV 13 \/ 6","offer_id":41902214480026,"sku":"P25S.0121H23F-6","price":92.99,"currency_code":"USD","in_stock":true},{"title":"MERV 8 \/ 12","offer_id":41902214512794,"sku":"P80S.0121H23F-12","price":109.99,"currency_code":"USD","in_stock":true},{"title":"MERV 11 \/ 12","offer_id":41902214545562,"sku":"P15S.0121H23F-12","price":143.99,"currency_code":"USD","in_stock":true},{"title":"MERV 13 \/ 12","offer_id":41902214578330,"sku":"P25S.0121H23F-12","price":182.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0591\/6937\/4362\/files\/21Hx23Fx1_MERV8_1pk.png?v=1790229381","url":"https:\/\/aerostarairfilters.com\/products\/21-1-2x23-3-8x1-air-filter","provider":"Aerostar Air Filters","version":"1.0","type":"link"}