Replacement Filters Compatible With Filtrete Air Purifiers | Filterbuy
November 7, 2026
Filtrete purifiers take replacement filters by size code, not by model name, which is how Filterbuy approaches every filter we make.
TL;DR
Most current Filtrete purifiers take one of two filters. Size F1, about 12 x 6.75 inches, fits the FAP-C01, FAP-T02, and FAP-ST02. Size F2/A2, about 13 x 8.2 inches, fits the FAP-C02, FAP-C03, FAP-T03, and FAP-SC02. Plan on a new filter every 3 to 12 months depending on daily run time, and do not wash it.
Key Takeaways
Filtrete sells purifier filters by size code. On most non-smart models, the last digit of the model suffix (1 or 2) tells you which one.
HEPA-type is not True HEPA. Filtrete rates HEPA-type at 95% of particles 2 microns and larger.
Filtrete's schedule adds up to about 2,200 hours of run time per filter.
Filtrete's warranty does not cover damage caused by alternate filters, so a compatible filter has to fit exactly.
When the AQI tops 100, Filterbuy recommends switching to a MERV 13 filter if you have an HVAC system and running a True HEPA purifier in each room.
Which Replacement Filter Does My Filtrete Air Purifier Use?
A Filtrete purifier's model number tells you which filter it takes. The compact FAP-C01 and the FAP-T02 and FAP-ST02 towers use Size F1. The FAP-C02, FAP-C03, FAP-T03 tower, and FAP-SC02 smart purifier use Size F2/A2. Older Ultra Clean units take FAPF02 or FAPF03 filters.
Filtrete Air Purifier Filter Finder
Approximate face dimensions. Confirm the code on your current filter.
The Filterbuy team noticed a shortcut here. On most non-smart Filtrete models, the last digit of the model suffix gives the size away: an FAP-C01BA-G1 takes Size F1, and an FAP-C02WA-G2 takes Size F2/A2. The smart FAP-ST02 is the exception, with Size F1.
To build the table, Filterbuy checked each model in November 2026 against 3M's compatibility lists and Filtrete's owner's manuals. The older Ultra Clean sizes come only from retailer listings, so measure those first.
Filtrete also makes filters for some Honeywell purifiers, which our Honeywell air purifier filter guide covers.
True HEPA Or HEPA-Type: Which Filtrete Filter Grade Fits Your Home?
Filtrete makes two grades in both F1 and F2 sizes, and either fits the same slot. The True HEPA grade is rated to capture 99.97% of particles as small as 0.3 microns. The HEPA-type grade is rated at 95% of particles 2 microns and larger, plus a carbon layer for odors.
Filtrete Filter Grades Compared
Ratings are Filtrete's published initial efficiency values.
Filterbuy's view as a filter maker: HEPA-type is not HEPA. For fine particles such as PM2.5 in smoke, True HEPA is the stronger pick, and AirNow's indoor air filtration fact sheet for wildfire smoke points to HEPA or other high-efficiency filters sized by CADR.
If odors are the bigger concern, Filtrete sells a 23.8 x 20.5 inch carbon pre-filter sheet that you trim to fit. Filterbuy cuts its own carbon pre-filters to exact size in its plant because a sheet trimmed a little short leaves a gap you cannot see once the cover goes back on, and air slips around the carbon. Trim yours to match the old sheet exactly. See how carbon and HEPA layers differ and what air purifier filters capture.
Filterbuy would choose in three steps:
Find the size code (F1, F2/A2, FAPF02, or FAPF03) on the old filter's frame or the unit label.
Pick True HEPA for smoke and other fine particles, or HEPA-type if odors matter more.
Want both? Add a carbon sheet to True HEPA, then date the filter by run time.
How Often Should You Replace A Filtrete Air Purifier Filter?
Filtrete ties its replacement schedule to daily run time: every 3 months at 24 hours a day, 6 months at 12 hours, and 12 months at 6 hours. Each works out to about 2,200 run hours per filter. Indoor tobacco smoke, candles, fireplace smoke, sanding, and pet dander can shorten that window.
Filtrete Filter Replacement Schedule
16 and 8 hour rows are Filterbuy estimates at about 2,200 run hours per filter.
The 2,200-hour figure is Filterbuy's math on Filtrete's published numbers. Divide it by your purifier's daily hours to set any schedule.
The filter light on the FAP-C01, FAP-C02, and FAP-C03 turns orange at about 10% filter life and red at 0%. A gray, dusty surface and weaker airflow are signs your air purifier filter is clogged even before the light changes. Read how often to replace air purifier filters by layer and how long HEPA air purifier filters last. On smoky days, running an air purifier when AQI is high can push you onto the 3-month schedule.
How To Change A Filtrete Air Purifier Filter And Reset The Light
To change the filter in a Filtrete FAP-C01, FAP-C02, or FAP-C03, turn it off, pull the top of the filter cover to remove it, and swap in a new filter facing the same way. Then seat the cover's two bottom knobs, press it shut until it locks, turn the unit on, and hold RESET for 3 seconds.
Tower and smart models open differently, so check your manual. If the light will not clear, these stuck filter light fixes cover the usual causes, and our air purifier filter direction guide helps confirm orientation.
Are Compatible Filters Safe To Use In A Filtrete Air Purifier?
A compatible filter can work in a Filtrete air purifier, as long as it matches the size code and dimensions exactly and states a capture rating. On the manufacturing side, fit decides performance: air takes the easiest path, and a short frame opens one around the media. The trade-off is warranty coverage: Filtrete's manuals say its warranty does not cover damage caused by alternate filters, which 3M has not evaluated.
The Federal Trade Commission's warning on warranty practices says requiring specific branded parts to keep a warranty is generally prohibited under the Magnuson-Moss Warranty Act unless those parts are free. Before you buy, check four things:
The listing names your exact Filtrete model and size code, such as F1 or F2/A2.
The face dimensions and depth match the filter you are replacing.
The capture claim names a particle size and percentage, not a vague "HEPA-like" label.
Odor filters disclose a real activated carbon layer.
Filtrete Purifier Filters Vs. Filtrete HVAC Filters
Despite the shared name, a Filtrete air purifier filter and a Filtrete HVAC filter are different products. One fits a room purifier, the other a central HVAC system. Filtrete also rates its HVAC filters on its own Microparticle Performance Rating (MPR) scale, while most other brands, Filterbuy included, use MERV. See how MPR, MERV, and FPR ratings compare.
As the U.S. Environmental Protection Agency (EPA) explains in its Guide to Air Cleaners in the Home, portable air cleaners filter a single room, while HVAC filters clean air throughout the home, which is why air filters and air purifiers complement each other. The same guide advises avoiding air cleaners that intentionally produce ozone, a lung irritant.
For wildfire smoke, the EPA advises a MERV 13 or higher HVAC filter if your system can handle it. Filterbuy's rule when the AQI tops 100: if you have an HVAC system, switch to an EPA-recommended MERV 13 air filter, and run HEPA air purifiers in each room, using the True HEPA grade in a Filtrete. Check your HVAC manual first. MERV 13 is not equivalent to True HEPA, which is why the rule calls for both.
Supporting Statistics
A Box Rating Is A Best Case
In a sealed National Institute of Standards and Technology (NIST) test house, a portable air cleaner removed 90% of injected particles in 2 hours.
With outdoor smoke PM2.5 seeping in, cleaning effectiveness fell to 45%–70%, depending on the room.
Size the purifier to its room and keep the filter fresh.
Power Costs Stay Low
ENERGY STAR certified room air cleaners are more than 50% more energy-efficient than standard models.
That saves about 211 kWh and $18–$40 a year.
At 24/7 use, plan on four filters a year.
Source: Air Cleaners
Ozone Limits Are Set In Law
Since 2010, California has required indoor air cleaners sold in the state to emit less than 0.050 parts per million of ozone.
Packaging must carry an "ARB Certified" label.
Filter-only purifiers stay well clear of that limit.
Source: California's Regulation to Limit Ozone Emissions from Indoor Air Cleaning Devices
Frequently Asked Questions
What Filter Does A Filtrete FAP-C02 Use?
The Filtrete FAP-C02 uses a Size F2/A2 filter, about 13 x 8.2 inches. The same filter fits the FAP-C03, FAP-T03, and FAP-SC02.
Can You Wash A Filtrete Air Purifier Filter?
No. Filtrete's owner's manuals say washing reduces the filter's effectiveness.
How Long Does A Filtrete Filter Last If I Run It Only At Night?
Plan on roughly 9 months at 8 hours a night, using the 2,200 run hours in Filtrete's schedule.
Does Filterbuy Sell Filtrete-Compatible Purifier Filters?
Not yet. Filterbuy will soon expand its air purifier filter line beyond its GermGuardian-compatible filters.
Filterbuy's Growing Air Purifier Filter Line
We do not offer Filtrete-compatible purifier filters yet. Today, we make purifier filters for select GermGuardian models in our own plants, and we will soon expand our air purifier filter product line with the same factory-direct pricing and quality. Browse our air purifier replacement filters or read our guide to choosing HEPA replacement filters. Our HVAC filters ship with fast and free 2-day delivery to most US states.
Glossary
A manufacturer of HVAC and air purifier filters sold factory-direct.
A 3M air filtration brand.
A Filtrete purifier filter about 12 x 6.75 inches.
A Filtrete purifier filter about 13 x 8.2 inches.
Media rated to capture 99.97% of particles as small as 0.3 microns.
Media styled after HEPA that does not meet the True HEPA rating.
Airborne particles 2.5 microns or smaller.
Air Quality Index, the EPA's daily air quality scale.
Clean air delivery rate, a purifier's filtered airflow.
Microparticle Performance Rating, Filtrete's HVAC filter scale.
Minimum Efficiency Reporting Value, the standard HVAC filter rating.
Trademark Disclaimer: Filterbuy is not affiliated with, authorized by, or endorsed by 3M or Filtrete. Filtrete is a trademark of 3M Company.