Fast, Free Shipping
Every Size
Made in the USA
Shop by
Actual Size: 20.88x20.88x0.75"
Merv 8
Standard
Merv 11
Superior
Merv 13
Optimal
Merv 8
Standard
Merv 11
Superior
Merv 13
Optimal
This is the second time I've purchased a box of six filters from Filterbuy. I originally purchased them because they were the only source that had my size for the same price as "normal" sized filters. I purchased from them again because of that and their prices are lower than anyone else for 21"x21" filters. Buying a box of six saves a lot of money too. I purchased Merv 8 filters this time, but I should have checked my previous order because I purchased Merv 11 then. These should be fine since they're still better than the filters I was buying from the previous place that were only 21"x20" filters. Since they were 1" shorter, I could not be sure that air was not bypassing the shorter side allowing dust and other allergens to re-enter the house. I will continue to purchase filters from Filterbuy for their great prices on multi-packs as well as that their prices on filter sizes that other places charge more for.
David S.
verified buyerEverything was as ordered
theodore s.
verified buyerSent back I got the wrong ones needed the MERV 8 and ordered those instead
Joseph R.
verified buyer
All air filters have a nominal size and an actual size.
The nominal size is rounded up to the nearest whole or half inch, and printed in a larger font.
The actual size is an exact physical measurement of the filter, printed in a smaller font.
21x21x1
Actual 20.88x20.88x0.75"
If the sizes printed on your current filter match the sizes shown above, this is your filter.
If your previous filter does not have dimensions printed on the frame, use a tape measure and record the length x width x depth. Then, round up to the nearest half inch to find the corresponding nominal size.
MERV 11 filters improve indoor air quality and ensure an efficient HVAC system by removing 95% of airborne pollutants while maintaining proper airflow.
These filters capture dust, lint, debris, mold, pollen, pet dander, dust mites, and auto emissions making sure they do not collect on your evaporator coil, in your furnace, or air ducts.
Filterbuy filters are more durable and effective than traditional fiberglass filters. All of our filters are constructed with pleated, reinforced, electrostatically charged filter media to optimize airflow. This design lasts 3x longer than fiberglass models, capturing harmful particles and improving air quality for all.
We care about the comfort and health of our customers. Our filters protect your home air quality from bacteria, dust, mold spores, and more - ideal for allergy and asthma sufferers. You can feel safe and breathe freely knowing your air, home, and health are protected.
Don't let your HVAC system fail you. Protect it and increase your system lifespan with Filterbuy replaceable air filters, designed to help you avoid future costly repairs. Filterbuy filters will improve your system efficiency, saving you money on energy costs. By choosing a high-quality air filter today, you are making your home a safer place for you and your family.
Our family-owned and operated company has evolved since its inception in 1958 to the filtration business that you know and love today. As our team has grown to nearly 1,000 employees, we have continued to keep our commitment to community investment and personal aid at every opportunity.
Our long lasting disposable filters need to be replaced less often, and nearly all material is recyclable.
Installation is simple. Each filter has an airflow arrow printed its side. This arrow must match the direction of the air when the filter is placed in your furnace or central air return ducts.
From our first air filter sold in 2013, we have proudly built our business in the USA, now manufacturing in Alabama, Pennsylvania, Texas, and Utah with additional distribution centers in California, Florida, and Illinois. This robust network gives us the unique ability to quickly fulfill diverse, custom orders to households and businesses across the country.
Scroll to see more.
MERV 8 | MERV 11 | MERV 13 | |
|---|---|---|---|
| Best for | Standard Residential/Commercial Healthy Families | Superior Residential/Commercial Allergy Sufferers | Optimal Residential/Commercial Hospital Grade |
| Comparible ratings | MPR 600 & FPR 5 | MPR 1000-1200 & FPR 7 | MPR 1500 - 1900 & FPR 10 |
| Filtration | Captures 90% of Airborne Particles | Captures 95% of Airborne Particles | Captures 98% of Airborne Particles |
| Dust, lint & debris | |||
| Mold, pollen | |||
| Dander, dust mites | |||
| Smoke & smog | |||
| Bacteria | |||
| Odor, vocs |
This is the second time I've purchased a box of six filters from Filterbuy. I originally purchased them because they were the only source that had my size for the same price as "normal" sized filters. I purchased from them again because of that and their prices are lower than anyone else for 21"x21" filters. Buying a box of six saves a lot of money too. I purchased Merv 8 filters this time, but I should have checked my previous order because I purchased Merv 11 then. These should be fine since they're still better than the filters I was buying from the previous place that were only 21"x20" filters. Since they were 1" shorter, I could not be sure that air was not bypassing the shorter side allowing dust and other allergens to re-enter the house. I will continue to purchase filters from Filterbuy for their great prices on multi-packs as well as that their prices on filter sizes that other places charge more for.
David S.
verified buyerEverything was as ordered
theodore s.
verified buyerSent back I got the wrong ones needed the MERV 8 and ordered those instead
Joseph R.
verified buyer
