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Actual Size: 21.25x21.25x4"
New look, same great filter
We’re updating the “look” of our filters.
While we do, your air filter will be the correct size & performance, but may look different than the image above. Learn more
Merv 8
Standard
Merv 11
Superior
Merv 13
Optimal
Merv 8
Standard
Merv 11
Superior
Merv 13
Optimal
Perfect, bought a few for the next several months, thank you for the quick process and delivery time
Suzanne S.
verified buyerGreat job!!
Stuart D.
verified buyerexcellent service and good experience...a guy who worked at Lowes told me about this company because Lowes did not carry the filter I needed. I went online to Filter Buy, and a couple days later, I had a box full of the right filters...I don't need to worry about buying another filter for years now!
Stephen A.
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.
21.25x21.25x4
Actual 21.25x21.25x4"
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 8 filters are the most popular MERV rating. They improve indoor air quality and ensure an efficient HVAC system by removing 90% of airborne pollutants while maintaining proper airflow.
These filters capture dust, lint, debris, mold, pollen, pet dander, and dust mites 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.
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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 |
Perfect, bought a few for the next several months, thank you for the quick process and delivery time
Suzanne S.
verified buyerGreat job!!
Stuart D.
verified buyerexcellent service and good experience...a guy who worked at Lowes told me about this company because Lowes did not carry the filter I needed. I went online to Filter Buy, and a couple days later, I had a box full of the right filters...I don't need to worry about buying another filter for years now!
Stephen A.
verified buyer
