16x25x1 Air Filters

16x25x1 furnace and HVAC filters, made in the USA in MERV 8, 11, 13, and Odor Eliminator

By Michelle Wan, Brand Manager and Air Quality Writer  |  Reviewed by David Clark, Licensed HVAC Technician, Filterbuy HVAC Solutions  |  Last updated August 14, 2026

TL;DR

A 16x25x1 air filter is a 1-inch pleated HVAC filter with a nominal size of 16 x 25 x 1 inches and an actual size of 15.50 x 24.50 x 0.75 inches. It is the most common furnace slot size in American homes. Filterbuy has cut this size in its own U.S. plants since 2013, in MERV 8, 11, 13 and Odor Eliminator, so these are production specs, not industry estimates. Replace it every 90 days.

Key takeaways

• A 16x25x1 filter does not measure 16 x 25 x 1 inches. Filterbuy cuts it to 15.50 x 24.50 x 0.75. The name is the nominal size, rounded up.

• The EPA recommends MERV 13 or as high a rating as your system fan and filter slot will take.

• A clean 1-inch MERV 13 adds 0.22 to 0.28 inches w.g. of resistance, against a whole-system budget of about 0.50.

• Replace a 16x25x1 furnace filter every 90 days, or every 60 days with pets and 45 with allergy sufferers.

• A Filterbuy 16x25x1 costs about $25 a year at four changes annually when bought by the dozen.

What Is a 16x25x1 Air Filter?

A 16x25x1 air filter is a disposable pleated filter that traps airborne particles before they reach your HVAC equipment and recirculate through your home. Every time your furnace or air conditioner runs, it pulls household air through a return opening. The 16x25x1 in that opening catches dust, pollen, mold spores and pet dander, and at higher ratings smoke and fine particulate.

That matters more than the price suggests: most of what anyone breathes at home has already passed through a filter like this one. Across the 600-plus sizes Filterbuy cuts, only the 20x20x1 leaves our plants more often than the 16x25x1.

A 16x25x1 furnace filter, HVAC filter and AC filter are the same product: a forced-air home shares one filter for heating and cooling. Not sure where yours sits? See where to find your HVAC air filter.

Is a 16x25x1 Filter Actually 16 X 25 X 1 Inches?

No. A Filterbuy 16x25x1 measures 15.50 x 24.50 x 0.75 inches. The 16 x 25 x 1 name is the nominal size, the convention for describing the slot. We cut length and width a half inch under nominal on purpose.

That half inch is a decision, not an accident. Cut it tighter and the filter binds going in; cut it looser and air slips around the frame instead of through the media. One caution from our floor: the convention is ours. It is not a published standard and it is not universal, which is why we print actual dimensions beside nominal ones rather than only the rounded number on the box.

Actual dimensions vary between brands, which is why a filter that fit snugly last time can bind or leak after you switch. We publish the comparison anyway, including where a competitor runs closer to nominal than we do, because you cannot check a fit nobody told you about:

Filterbuy dimensions are production-line specs. Competitor dimensions are from each manufacturer's published retail listings, August 2026.

The EPA puts the rule plainly: a filter should fit snugly without leaking air around it, and should never be bent or crushed to fit. If your slot lands on a true fraction rather than close to a whole inch, that is a custom slot, so do not round. Full method: how to measure your air filter.

What HVAC Systems Use a 16x25x1 Filter?

The 16x25x1 is the most common furnace slot size in American homes, and the second most ordered filter size overall after the 20x20x1. It sits in a filter slot at the furnace or air handler, or in a wall or ceiling return grille. Furnace slots run larger, which is why the 16x25x1 lands there most often.

It fits most residential equipment, including Lennox, Trane, Carrier, Rheem, Goodman, American Standard, York, and Bryant. Your HVAC brand does not set your filter size. Your slot does.

The Filterbuy 16x25x1 also replaces any other brand's 16x25x1 directly:

MPR and FPR are proprietary scales developed by 3M and The Home Depot, so equivalencies are approximate rather than exact.

Homes with more than one return need a filter in each, and they are not always the same size. Sizing is the question our customer service team answers most, and the cause is structural: builders frame the filter compartment to the ductwork, and ductwork does not care what a catalog stocks.

Non-standard slots are commoner than this category admits, which is why Filterbuy cuts custom air filters from scratch to your measurements rather than trimming a stock filter to fit.

Which MERV Rating Should You Choose for a 16x25x1?

The 16x25x1 comes in four filtration levels. Choose MERV 8 for general dust, MERV 11 for allergies and pets, MERV 13 for smoke and fine particulate, and Odor Eliminator when smells are the problem. MERV, or Minimum Efficiency Reporting Value, is the industry scale defined by ANSI/ASHRAE Standard 52.2. The EPA notes that MERV rests on a national consensus standard while MPR and FPR are proprietary.

Filterbuy publishes the ASHRAE minimums by particle size rather than one headline percentage. "Captures 90% of airborne particles" tells you nothing about whether a filter stops the smoke particle you are worried about. The size bands do:

Higher is not automatically better: every step up captures more and resists airflow more. Filterbuy cuts the 16x25x1 in all four levels; compare them on the MERV rating chart, or go straight to 16x25x1 MERV 13 filters.

Does a MERV 13 16x25x1 Filter Restrict Airflow?

A MERV 13 16x25x1 does restrict airflow, but far less than most people fear. Every filter creates resistance and higher MERV creates more. What matters is the number, and almost nobody in this category publishes one. We can, because we make what we sell: the figures below come from our own testing lab, on a line that has produced more than two million filters.

Initial pressure drop for 1-inch Filterbuy pleated filters, from our own laboratory testing. Total external static pressure includes ducts, coils and registers, not the filter alone.

One detail worth knowing if you are cross-shopping sizes: 16 x 25 is 400 square inches of filter face, the same as a 20x20x1 and 100 square inches less than a 20x25x1. Resistance at a given airflow tracks face area, and our size data shows it. At 1,000 CFM our MERV 13 20x20x1 measures 0.25 in. w.g. while the larger-faced 20x25x1 measures 0.22. A 16x25x1 sits with the 20x20x1, at the upper end of the 1-inch range.

A related thing shoppers are routinely told wrong: more pleats does not mean more filter. Our 1-inch carries 14 pleats per foot and our 4-inch carries 8. Fewer pleats, each far deeper. Depth is what buys surface area and lowers resistance. Pleat count is not the number to shop on.

Which MERV Rating Can Your System Handle in a 16x25x1?

A system installed since 2015 can generally run a MERV 13 16x25x1; equipment from before 2005 should step down to MERV 8. How much resistance a system absorbs depends less on the filter than on the age of the equipment pulling air through it. This is the guidance Filterbuy gives its own customers:

Filterbuy guidance based on typical residential system specifications. Verify against your equipment manual. A starting point, not a verdict: ductwork and return sizing matter as much as system age.

Treat that as a starting point, not a verdict. A 1998 system with generous ductwork may run a MERV 13 without complaint; a 2020 system with one undersized return may not. If you upgrade and the house takes longer to reach temperature, or a return vent whistles, you have your answer.

A clean MERV 13 uses roughly half a residential system's static pressure budget before ducts and coils are counted, which is why the calendar matters more than the rating. A clogged MERV 8 restricts airflow more than a clean MERV 13. The EPA advises that most furnaces and HVAC systems handle a MERV 13 without equipment problems, provided the filter is replaced frequently. On a pre-2005 system or undersized ductwork, have a technician measure static pressure first.

How Often Should You Replace a 16x25x1 Filter?

Filterbuy's baseline for a 16x25x1 air filter is every 90 days. Shorten that to 60 days in a home with pets, 45 days if someone has asthma or allergies, and 30 days during wildfire smoke or active renovation. What drives the interval is what is in your air, not the MERV rating on the frame.

ENERGY STAR advises checking the filter monthly and changing it at minimum every three months.

Two identical MERV 13s, one in a house with three dogs and one in a sealed condo, will not reach ninety days together. The check takes five seconds: hold the 16x25x1 up to a light, and if light no longer passes through the pleats, replace it.

ENERGY STAR reports that nearly half of a home's energy goes to heating and cooling, and a dirty filter slows airflow and makes the system work harder for the same result.

Most homes use four 16x25x1 filters a year. The per-filter price drops about 74% between a single filter and a 12-pack:

Pricing as of August 2026. Auto Delivery saves an additional 5%.

Filterbuy built auto delivery around the actual failure point. Almost nobody decides a filter is not worth changing; they just do not notice ninety days went by. A 12-pack covers three years in a single-return home, and a scheduled delivery removes the step that reliably gets skipped.

How Do You Install a 16x25x1 Filter?

A 16x25x1 furnace filter takes under a minute to fit, and the only step people get wrong is the arrow. Every Filterbuy 16x25x1 has it printed on the frame edge, pointing toward the furnace or air handler. Turn the system off, note which way the old one faced, and match it.

1. Turn the system off at the thermostat.

2. Open the grille or filter slot. Grilles have a latch or clips; furnace slots have a removable cover.

3. Slide the old filter out and note which way its arrow points.

4. Check the arrow on the new 16x25x1. It points toward the furnace or air handler, away from the room.

5. Slide the new filter in flat, with no bowing and no gap wider than about a quarter inch.

6. Close the cover, restart the system, and write the date on the frame.

A backward filter still works, but less efficiently, and the pleats can collapse. If your slot is four inches deep you need 16x25x4 filters instead, since the two are not interchangeable. Related sizes: 16x20x1 and 20x25x1.

What a 16x25x1 Filter Will Not Do

A 16x25x1 filter cleans the air that passes through it, and nothing else. Filterbuy sells these for a living and would still rather you knew the limits than bought one expecting it to solve something it cannot touch.

• It only works while the system runs. The EPA notes most HVAC systems run less than 25% of the time during heating and cooling seasons, so the filter is idle most of the day. Running the fan on circulate helps more than upgrading MERV.

• It does not remove radon or carbon monoxide. Both are gases that pass straight through pleated media. Radon needs testing and mitigation; carbon monoxide needs a detector.

• It will not fix a mold problem. Mold is a moisture problem. A filter may catch some spores in circulation, but the EPA is clear that air cleaning does not address the water source causing the growth.

• It is not a HEPA filter. True HEPA sits at MERV 17-20 and needs a system built for it. A Filterbuy MERV 13 is the practical ceiling for a 1-inch slot: a real step up, not a substitute.

• It cannot outperform a bad seal. A gappy filter slot lets air route around the media entirely. Fixing the fit is worth more than raising the rating.

Glossary

16x25x1 air filter. A 1-inch pleated HVAC filter, nominal size 16 x 25 x 1 inches. The Filterbuy 16x25x1 measures 15.50 x 24.50 x 0.75 inches.

MERV. Minimum Efficiency Reporting Value. The industry scale, defined by ANSI/ASHRAE Standard 52.2, rating how much of a given particle size a filter captures.

Nominal size. The rounded size printed on the frame, such as 16 x 25 x 1. It describes the slot, not the filter.

Total external static pressure. The whole system's resistance: filter, ducts, coils and registers. Most residential systems are designed for 0.50 in. w.g. or less.

Activated carbon. Treated media that adsorbs odors and VOCs, paired with pleated filtration in the Filterbuy Odor Eliminator.

Frequently Asked Questions

Is a 16x25x1 furnace filter the same as a 16x25x1 HVAC filter?

Yes. A 16x25x1 furnace filter, HVAC filter, and AC filter are the same product. A forced-air home uses one filter for both heating and cooling.

Which way does the arrow point on a 16x25x1 filter?

The arrow points toward the furnace or air handler, in the direction air is moving, away from the room. In a wall or ceiling return grille, it points into the wall or ceiling.

Should I clean a 16x25x1 air filter?

No. Filterbuy 16x25x1 pleated filters are disposable and are not built to be washed. Rinsing collapses the media and warps the frame, letting unfiltered air bypass it. Replace it instead. Only filters explicitly labeled washable should be cleaned.

What happens if I don't change my 16x25x1 filter?

It clogs until airflow drops sharply. The system runs longer for the same result, energy costs rise, and particles begin bypassing the filter. Extended neglect can freeze the evaporator coil.

Where are Filterbuy 16x25x1 filters made?

Filterbuy manufactures 100% of its filters in the USA and sold its first in 2013. The company is second-generation family-owned and ships factory-direct.

Supporting Statistics

Three findings from federal and public-health sources that back the 16x25x1 guidance on this page.

1. Indoor pollutant concentrations often run 2 to 5 times higher than outdoors.

The U.S. EPA reports that Americans spend roughly 90% of their time indoors, where concentrations of some pollutants often run two to five times higher than typical outdoor levels. While the system runs, the 16x25x1 filter in the return is the only thing cleaning that air. Source: EPA, Report on the Environment: Indoor Air Quality.

2. Two-thirds of U.S. households run a central, ducted system.

The 2020 Residential Energy Consumption Survey found that 88% of U.S. households use air conditioning, and two-thirds use central AC or a central heat pump as their main equipment. Those ducted systems are the ones that take a filter like the Filterbuy 16x25x1. Source: U.S. Energy Information Administration, RECS 2020.

3. 76 million Americans live in counties failing for year-round particle pollution.

The American Lung Association graded counties holding 76 million people as failing for year-round particle pollution in its "State of the Air" 2026 report, and 61.5 million for short-term spikes. Fine particulate is what separates a MERV 13 from a MERV 8, and those spikes are why the schedule above drops to 30 days during wildfire smoke. Source: American Lung Association, State of the Air 2026.

Sources

U.S. EPA, Guide to Air Cleaners in the Home · ENERGY STAR, Heat & Cool Efficiently · EPA Report on the Environment · U.S. Energy Information Administration, RECS · American Lung Association, State of the Air 2026 · ANSI/ASHRAE Standard 52.2 · Filterbuy manufacturing and laboratory testing data.