20X25X5 REPLACEMENT AIR FILTERS
Did you know that there are 5 different 'actual' sizes of 20x25x5 branded filters? These sizes are not interchangeable, but we're guaranteed to have the right replacement for your HVAC unit. Simply select one of the following from the drop down below to find the best fit for your furnace:
Confused with all the choices of 20x25x5 filters? You're not alone. Even though these filters carry the same nominal size, they range from only 4.25" thick to over 5.25" thick. The difference in these sizes is just enough to make them unique and not interchangeable.
Unfortunately, the fact that they are not interchangeable is not a coincidence. The major HVAC brand manufacturers would prefer you to purchase their (overpriced) OEM replacements for your unit. Given there are so many different varieties, no local box store can stock them all.
At FilterBuy our mission is to change that. We have the largest selection of OEM replacements available and do our best to keep up with any new sizes that the OEM companies bring to market.
We offer a full variety of MERV ratings (MERV 8, 11, and 13) in each of our aftermarket replacements, giving the consumer the most choice possible. Ironically, even our most effective (MERV 13) replacements are generally more cost effective than the original OEM replacements.
We do our best to keep our list up to date, but if you have a part number for a 20x25x5 air filter that you don't see listed here and would like us to add it, send it to us in our contact form and we will add it. Not only will it hopefully help you, but it provides a service to similar customer looking for the same filter in the future.
20x25x5 Air Filters
By Michelle Wan, Brand Manager and Air Quality Writer | Reviewed by David Clark, Licensed HVAC Technician | Updated October 1, 2026
TL;DR
A 20x25x5 air filter is a 5-inch-deep whole-house media filter that slides into the filter cabinet on a furnace, air handler, or heat pump. "20x25x5" is a nominal label, not a measurement. Filterbuy manufactures three different actual sizes under it, and they do not interchange. Match your filter by brand, OEM part number, or actual size, then choose MERV 8, MERV 11, or MERV 13 based on what you need it to catch.
Key Takeaways
No 20x25x5 filter actually measures 20 x 25 x 5 inches. A Honeywell measures 19.88 x 24.75 x 4.38 inches; a Goodman measures 20.19 x 25.31 x 5.25 inches.
MERV 8 traps 90% of airborne particles, MERV 11 traps 95%, and MERV 13 traps 98%. All three fit the same cabinet and last the same 90 days.
How fast a filter loads depends more on your household than on its MERV rating, so inspect the first one rather than trusting the calendar.
Washable 20x25x5 filters exist, but most are not formally MERV-rated. Filterbuy does not make one, and this page explains honestly when one is still the better choice.
What Is A 20x25x5 Air Filter?
A 20x25x5 air filter is a deep-pleated whole-house media filter for the cabinet on a residential furnace, air conditioner, air handler, or heat pump. The five inches are depth, and that depth is the point: a 5-inch filter packs several times the media of a 1-inch into the same opening, so it captures more without making your blower work harder.
Honeywell, Lennox, Carrier, and Trion Air Bear systems all ship with 5-inch cabinets, and a thinner filter will not seal in one.
What Size Is A 20x25x5 Air Filter, Actually?
No filter sold as 20x25x5 actually measures 20 by 25 by 5 inches. Every filter is trimmed slightly undersized so it slides into the cabinet without forcing or bowing, and each HVAC manufacturer trims to its own spec. That is why a filter that seats perfectly in a Honeywell cabinet will not fit a Goodman one.
Filterbuy manufactures three actual sizes under this label. Find your brand below and match the actual size, not the number printed on the box.
Filterbuy manufactures all three sizes. Don't see your part number? Send it to us and we'll add it.
Filterbuy is in an unusual position to publish this. We manufacture all three sizes at our own U.S. plants, so the cross-reference above comes off our production line rather than a competitor’s spec sheet. Each OEM documents only its own trim, and no store stocks all three, so this table is hard to find elsewhere.
“20x25x5 is a shopping label, not a measurement. We make all three of the filters sold under it, so we can tell you plainly which one fits your cabinet. A store shelf cannot do that.”
Brand Manager and Air Quality Writer, Filterbuy
Shop by brand: 20x25x5 Honeywell filters, 20x25x5 Lennox filters, 20x25x5 Carrier filters, or 20x25x5 Trion Air Bear filters.
How Do I Find Which 20x25x5 Filter Fits My Unit?
There are three ways to identify the right filter, in order of speed. Read the actual size printed on the frame of your old filter. If that is unreadable, find the OEM part number stamped on the sticker inside your filter cabinet door. If neither is available, pull the old filter and measure it. Any one of the three will land you on the correct size in under two minutes.
Check the old filter frame. Most filters print the actual size in smaller type beneath the nominal size, something like 19.88 x 24.75 x 4.38". That number is your answer.
Look for the OEM part number. It is on a sticker inside the cabinet door or on the housing: numbers like FC100A1037, X6673, or 229990-102. Search it in the list on this page.
Measure it yourself. Pull the old filter and measure height x width x depth to the nearest eighth of an inch. Do not round up. The exact number is the point.
One thing the Filterbuy manufacturing team tells every customer: measure all three dimensions, not just length and width. A wrong depth is the most common ordering mistake we see.
Our guide to measuring your air filter covers a missing frame label.
MERV 8 Vs. MERV 11 Vs. MERV 13 In A 20x25x5 Filter
All three ratings fit the same cabinet and last the same 90 days. The difference is what they catch. MERV 8 traps 90% of airborne particles and handles everyday dust and pollen. MERV 11 traps 95% and is the pick for pet owners and allergy sufferers. MERV 13 traps 98%, including smoke and virus-carrying particles.
MERV is the industry-standard filtration scale defined by ANSI/ASHRAE Standard 52.2.
MERV is the ASHRAE Standard 52.2 filtration scale. MPR and FPR are proprietary scales used by 3M and The Home Depot.
For most homes shopping the best air filters in 20x25x5, MERV 11 is the sweet spot. Step up to MERV 13 if someone has asthma or you live where wildfire smoke is a seasonal reality. The U.S. EPA recommends MERV 13, or as high as your system can handle during smoke events. See our guide to the best MERV filter for wildfire smoke.
One clarification from our reviewer. David Clark, a licensed HVAC technician, notes that the airflow warnings about high-MERV filters were written about 1-inch filters. A 20x25x5 holds several times the media in the same opening, so air passes through more surface area at lower resistance.
Shop by rating: MERV 8 air filters, MERV 11 air filters, MERV 13 air filters. For the full scale and what each number captures, see our guide to MERV ratings.
Are There Washable 20x25x5 Furnace Filters?
Yes, and Filterbuy does not make one, so here is the straight version. Washable 20x25x5 furnace filters are made by K&N, Cycle Air, and several marketplace brands, usually as electrostatic media in an aluminum frame. They genuinely cut waste and long-run cost. The trade-off is filtration: most washable electrostatic media carries no formal MERV rating, and performance depends on washing it correctly and drying it completely.
A damp filter returned to a dark cabinet is a mold risk, and it is the part of washable ownership people underestimate most.
After more than a decade of manufacturing filters and serving over two million households, Filterbuy has learned that no single filter type solves every air quality problem. If cutting waste is your priority and you will commit to the cleaning schedule, a washable filter is a reasonable choice. We would rather you buy the right thing than the thing we sell. If anyone in your home has allergies or asthma, verified capture matters more.
Where Can I Buy 20x25x5 Air Filters Near Me?
Big-box stores typically stock one of the three actual sizes, so the filter on the shelf often does not seat properly. Filterbuy manufactures all three in Talladega, Alabama and three other U.S. plants, and ships factory-direct within 24 hours. That is usually faster than a second store trip after the first one did not fit.
Before you drive anywhere, confirm the actual size on your old filter and whether the store carries that trimmed size. A filter a quarter-inch too small lets unfiltered air bypass the media entirely.
Searching for 20x25x5 air filters nearby usually means you need one this week. Every Filterbuy filter is built in one of our four American factories.
How Often Should You Replace A 20x25x5 Filter?
Every 90 days is the starting point, but look at it before you trust the calendar. Berkeley Lab found that filter loading varied more between households than between MERV ratings, so your neighbor’s schedule tells you almost nothing about yours. Shorten to 60 days with pets or during smoke season, and 30-45 days for significant allergies.
Look at the spread in that study. In seven of the ten monitored homes, pressure across the filter rose only about 5% over the entire period. The fastest-loading home was the most rural one, which also had two large dogs. Dust load is a property of your house, not your filter.
So run the first cycle as an experiment. Check the filter at 60 days, hold it up to a light, and set your own interval from what you see. If it still looks clean at 90 days, you probably have room to stretch it, and Filterbuy would rather sell you the right number of filters than the maximum number. Once you know your interval, air filter auto-delivery ships your exact size on it. At multi-pack pricing a 20x25x5 runs roughly 25 to 40 cents a day.
Supporting statistics
Deep filters flow better than thin ones and load about half as fast. Lawrence Berkeley National Laboratory monitored ten homes for a year and measured an average pressure drop of 94 Pa across four-inch filters versus 110 Pa across one-inch, with the deep filters loading at roughly half the rate. MERV 10-13 filters changed household energy use by less than 1%. Walker et al., Berkeley Lab, 2013
Indoor air is where the exposure actually happens. The U.S. Environmental Protection Agency reports that Americans spend roughly 90% of their time indoors, where concentrations of some pollutants run two to five times higher than typical outdoor levels. EPA, Report on the Environment
Dust mite allergy affects 20 million people in the United States. AAFA also reports 82 million diagnosed seasonal allergy cases in 2024, about 1 in 4 adults. Dust mite debris and pollen are what MERV 11 media is built to capture. AAFA, Allergy Facts and Figures, April 2026
Frequently Asked Questions
Can I Use A 20x25x4 Filter In A 20x25x5 Slot?
Usually not. A 4-inch filter in a 5-inch cabinet leaves a gap, and air takes the path of least resistance, going around the filter instead of through it. Match the depth your cabinet was built for.
Why Is My 20x25x5 Filter Smaller Than 20x25x5?
On purpose. The label is rounded for shopping; the frame is cut to clear the cabinet rails. A Honeywell 20x25x5 measures 19.88 x 24.75 x 4.38 inches.
Which Way Do The Arrows Face On A 20x25x5 Filter?
The airflow arrow points toward the furnace or air handler, away from the return duct. Installed backward, the pleats can collapse under pressure.
Are Filterbuy 20x25x5 Filters Made In The USA?
Yes. Every Filterbuy filter is built in the United States, at our plants in Alabama, Florida, Pennsylvania, and Utah, using recyclable materials.
Ready to order?
Find your filter by brand, part number, or actual size using the selector above, then choose MERV 8, 11, or 13. Every Filterbuy filter is made in the USA and ships free within 24 hours.
About the author and reviewer
Michelle Wan is Filterbuy’s Brand Manager and Air Quality Writer. She works directly with our U.S. manufacturing teams.
David Clark is a Licensed HVAC Technician and CEO of Filterbuy HVAC Solutions. He reviewed this page for accuracy.
Sources
ANSI/ASHRAE Standard 52.2: MERV test method
U.S. EPA: Reduce Your Smoke Exposure
Actual dimensions come from Filterbuy manufacturing specifications.
Glossary
20x25x5 air filter: A 5-inch-deep whole-house pleated media filter for a residential furnace, air handler, or heat pump. Filterbuy makes three actual sizes under this one nominal label.
Nominal size: The rounded size printed on a filter box, such as 20x25x5. A compatibility label, not a measurement.
Actual size: The true trimmed dimensions of a filter, such as 19.88 x 24.75 x 4.38 inches. The number that determines fit.
MERV: Minimum Efficiency Reporting Value, the industry-standard filtration scale defined by ASHRAE Standard 52.2. Higher numbers capture smaller particles.
MPR: Micro-Particle Performance Rating, a proprietary filtration scale used by 3M Filtrete. Roughly convertible to MERV.
FPR: Filter Performance Rating, a proprietary 1-10 filtration scale used by The Home Depot.
Media filter: A filter using a deep bed of pleated material rather than a thin flat panel, allowing high MERV ratings without restricting airflow.
Filter cabinet: The housing on an HVAC system that holds the filter. Its depth determines which size you can use.