Actual Size: 19 1/2" x 24 1/2" x 3/4"
3 month filters
2. Select Quantity
Buying multiple sizes?
Made in the USA
Ships in 24 hours
Available In MERV Rating: 8, 13, 11, Odor Eliminator
Made in the USA
Ships in 24 hours
Scroll to see more.
 MERV 8 |  MERV 11 |  MERV 13 |  Odor Eliminator | |
|---|---|---|---|---|
| Best for | Standard Residential/Commercial Healthy Families | Superior Residential/Commercial Allergy Sufferers | Optimal Residential/Commercial Hospital Grade | ODOR ELIMINATOR Residential/Commercial Household Odors |
| Comparable ratings | MPR 600 & FPR 5 | MPR 1000-1200 & FPR 7 | MPR 1500 - 1900 & FPR 10 | MPR 1000-1200 & FPR 7 |
| Filtration | Captures 90% of Airborne Particles | Captures 95% of Airborne Particles | Captures 98% of Airborne Particles | Captures 95% of Airborne Particles |
| Dust, lint & debris | ||||
| Mold, pollen | ||||
| Dander, dust mites | ||||
| Smoke & Smog | ||||
| Bacteria | ||||
| Odor, vocs |
Generally, we recommend you replace your air filters every 90 days. Find out below if you should change your filters more often.
Change your filter every
6 weeks
to ensure indoor air quality is at its best.
Change your filter every
2 months
to avoid shedding and odor buildup.
Change your filter every
2-3 months
as having clean air is even more important with children in your home.
Change your filter every
6 weeks
to ensure indoor air quality is at its best.
Change your filter every
2 months
to avoid shedding and odor buildup.
Change your filter every
2-3 months
as having clean air is even more important with children in your home.
Actual Size: 19½" × 24½" × ¾"
Author: Michelle Wan, Brand Manager and Air Quality Writer | Technically Reviewed By: David Clark, Licensed HVAC Technician
Published: August 7, 2026 | Updated: August 7, 2026
A 20x25x1 air filter is a one-inch pleated HVAC filter measuring 19½" × 24½" × ¾", and it fits most 2.5 to 3 ton residential systems. Filterbuy manufactures 20x25x1 air filters in MERV 8, MERV 11, MERV 13, and Odor Eliminator at four U.S. factories, and orders ship in 24 hours from $6.66 per filter.
The nominal size 20x25x1 describes a filter whose actual dimensions are 19½" × 24½" × ¾". Every manufacturer undercuts it so the filter seats without binding.
MERV rating, not size, determines what a 20x25x1 filter captures. MERV 8 handles dust and pollen, MERV 11 adds dander and mold spores, MERV 13 adds smoke and bacteria.
The U.S. Environmental Protection Agency recommends a filter rated MERV 13, or the highest rating your fan and filter slot will accommodate.
Bought twelve at a time, a Filterbuy 20x25x1 MERV 8 filter costs about $26.64 a year at 90-day changes, roughly seven cents a day.
A 20x25x1 air filter is a one-inch pleated HVAC filter with nominal dimensions of 20 by 25 by 1 inches and actual dimensions of 19½" × 24½" × ¾". It sits in the return air path and catches particles before they reach the blower and coil. It is one of the most common residential sizes in the U.S.
Nominal versus actual sizing causes more confusion than anything else we field. The gap is deliberate. We cut a 20x25x1 to 19½" × 24½" on purpose, because slots are stamped with real-world tolerance and a filter cut to a true 20 by 25 would bind or bow. That undercut is what lets one filter fit every cabinet.
Filterbuy has manufactured pleated air filters in the United States since 2013. We build more than 600 sizes at our factories in Alabama, Florida, Pennsylvania, and Utah.
Choose MERV 8 for a healthy household with no pets, MERV 11 for allergies, asthma, or one pet, and MERV 13 for severe allergies, multiple pets, or wildfire smoke. All four Filterbuy 20x25x1 options fit the same slot, so the rating is purely a filtration decision. MERV, or Minimum Efficiency Reporting Value, is the industry standard set by ASHRAE.
Values are ASHRAE 52.2 minimums. Higher MERV media adds resistance, but the limit is set by blower and duct design, not the number. The EPA notes most systems accommodate MERV 13 when the filter is replaced frequently. The next section is how to confirm yours does.
"The question we get most is whether MERV 13 will hurt the system. In a modern home, almost never. What actually hurts systems is the filter nobody remembered to change. I would rather you run MERV 11 on a real schedule than MERV 13 for eight months."
Michelle Wan, Brand Manager and Air Quality Writer, Filterbuy
The best 20x25x1 air filter is the highest rating your system can pull through and your household actually needs. For most homes that is MERV 11, which is also what the American College of Allergy, Asthma & Immunology recommends MERV 11 to 13 for whole-house filtration. Match your situation below, including wildfire smoke and odor.
Install the Filterbuy MERV 13, run it a week, and watch for four things. You do not need a technician, just one filter and seven days.
Listen at the return grille. A new whistle, or a louder rush of air than usual, means the blower is straining against the media.
Check the farthest supply vent. Hold your hand at the vent furthest from the air handler. Weaker than before is the clearest sign.
Watch your run times. Cycles that stretch longer without a weather change point to restricted airflow.
In cooling season, look at the line set. Frost or ice on the copper line entering the air handler means airflow has dropped far enough to freeze the coil. Shut the system off and step back to MERV 11.
If none appear, your system is fine on MERV 13. Check again at day 45, when the filter is loaded and resistance is highest. That is where a marginal system shows itself, not day one.
Yes, if your slot measures 19½" × 24½" × ¾". One Filterbuy 20x25x1 serves both the furnace and the air conditioner, because in a central system they share one air handler and one return duct. There is no separate 20x25x1 HVAC filter and air conditioner filter.
Almost every exchange we process traces to one habit: measuring the old filter instead of the opening it sits in. Measure the slot. If it does not match, an adjacent size will.
A Filterbuy 20x25x1 filter costs $26.64 to $111.96 per year at the 90-day interval, depending on how many you buy at once. Four cover a year. We manufacture and ship these ourselves, factory direct, so nothing sits between our plant and your door.
MERV 8 pricing at four changes per year. MERV 11 and MERV 13 follow the same quantity structure.
Cheap air filters are not always the cheapest. The ACAAI reports that fiberglass furnace filters have been shown ineffective, and buying one at a time costs four times the case price.
Filterbuy 20x25x1 filters replace Honeywell, Filtrete, Rheem, Trane, Lennox, and Carrier filters of the same size. Switching brands is only a matter of matching performance. The difficulty is that three scales are in circulation: MERV from ASHRAE, MPR from 3M, FPR from The Home Depot.
Equivalences are approximate. MERV is the only scale set by a national consensus standard.
The EPA states that MERV is based on a national consensus standard while FPR and MPR are proprietary. Match the MERV rating and you have matched the performance.
Change a Filterbuy 20x25x1 air filter every 90 days in a standard household, 60 with one pet, and 45 with multiple pets or severe allergies. Basement mechanical rooms load faster, so use 60 there regardless.
Inspect monthly. Hold it to a light, and if no light comes through, it is due.
Filterbuy 20x25x1 pleated filters are disposable. Never wash or vacuum one. We apply an electrostatic charge to the media during manufacturing, and water strips it. The ACAAI makes the same point, noting it is nearly impossible to clean a permanent filter of the particles that cause allergies. Only metal-framed washable filters are meant to be rinsed.
The most common filter problem we see is not the wrong size or rating. It is a filter left in for eight months. Filterbuy Auto Delivery ships every 30, 60, or 90 days at 5% off. If your target is 45, choose 30. A spare in the closet costs nothing; a loaded filter costs you every day it stays in.
Three findings from federal and public-health sources behind the guidance above.
Most U.S. homes run a central system.
88% of U.S. homes have air conditioning. 66% have central systems. (U.S. Department of Energy)
They use about 12% of U.S. household electricity, roughly $29 billion a year.
Heating and cooling is your biggest energy load.
Asthma is common, and its triggers are airborne.
More than 28 million people in the U.S. have asthma. (Asthma and Allergy Foundation of America)
8.6% of adults and 6.5% of children currently have asthma. (CDC, 2024)
Pollen, pet dander, and mold spores are common triggers. Hence the MERV 11 and 13 picks above.
Yes. Both describe the same filter. Manufacturers list length and width in either order. If your old filter reads 25x20x1, order 20x25x1.
Toward the furnace or air handler. That is the direction air travels, away from the return duct. Note it before you pull the old filter.
Some systems have one filter at the return grille and another at the air handler. Both need changing. Do not put a high MERV rating in both, because filters in series add their resistance. ASHRAE advises upgrading one. Run MERV 8 at the grille, your rating at the handler.
Yes, when the rating matches the allergen. Pollen sits at 3 to 10 microns, which MERV 8 captures. Dander and mold spores sit at 1 to 3 microns, where MERV 11 captures 65% or more and MERV 13 at least 85%.
MERV. Minimum Efficiency Reporting Value, the ASHRAE 52.2 standard that rates how much a filter captures in three particle-size bands. Higher numbers capture more.
MPR. Microparticle Performance Rating, a proprietary 3M scale used on Filtrete filters. Not interchangeable with MERV.
FPR. Filter Performance Rating, a proprietary scale used by The Home Depot on Honeywell and house-brand filters.
Nominal size. The rounded size printed on the filter frame, such as 20x25x1. What you order by.
Odor Eliminator. A Filterbuy pleated filter with an activated carbon layer. Carbon adsorbs odors and gases that pleated media alone passes straight through.
ASHRAE. The American Society of Heating, Refrigerating and Air-Conditioning Engineers, which writes Standard 52.2 and sets MERV.
Michelle Wan is Filterbuy's Brand Manager and Air Quality Writer. She works with the company's U.S. manufacturing team to turn MERV ratings and HVAC efficiency into advice homeowners can act on. Technically reviewed by David Clark, Licensed HVAC Technician.
