Our Accumulair 20x21x4 air filter is solely built to be compatible with similarly sized 20x21x4 air filter specs. Pleated electrostatically charged filter media captures contaminants according to the MERV standard specification. Free of chemicals. Note: The example filter image as shown is not to scale and is shown for style purposes only. Database and 20x21x4 air filter specs are up to date as of 03/24/2020.
Shipping and Returns
- Shipping is FREE to the contiguous United States.
- Our current lead times are 3-5 business days for stocked filters (standard 1"-5" thick sizes), up to 3 weeks for made-to-order filters (non-standard and 0.5" sizes).
Delivery normally takes another 1-3 days depending on location.
- 30-day 100% return policy.
Payment & Security
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