How Long Do HEPA Air Purifier Filters Last?
Read moreComplete filters for air purifiers. HEPA media and activated carbon in one drop-in unit.
Your purifier's model number is on a label on the back or underside of the unit.
Filter B Replacement, HEPA + Activated Carbon
Replacement for GermGuardian Filter B (FLT4825) · Fits AC4300 / AC4800 / AC4900-series · 4 × 16 in
Filter C Replacement, HEPA + Activated Carbon
Replacement for GermGuardian Filter C (FLT5000) · Fits AC5000-series · 4 × 19 in
Filter E Replacement, HEPA + Activated Carbon
Replacement for GermGuardian Filter E (FLT4100) · Fits AC4100 / AC4150 / AC4175-series · 4 × 8 in
Made in the USA
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Your air purifier filter includes a carbon pre-filter. Want backups on hand? Cut Carbon pre-filters are sold separately.
Cut Carbon Filter B Pre-Filter, 4-Pack
Pairs with the GermGuardian B HEPA filter · 15.5 × 4.50 × 0.2 in
Visit product page →
Cut Carbon Filter C Pre-Filter, 4-Pack
Pairs with the GermGuardian C HEPA filter · 19.25 × 4.50 × 0.2 in
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Cut Carbon Filter E Pre-Filter, 4-Pack
Pairs with the GermGuardian E HEPA filter · 8.0 × 4.50 × 0.2 in
Visit product page →Looking for a different size, or a Cut Carbon pre-filter for a non-GermGuardian purifier? Browse the full Cut Carbon pre-filter lineup, including Honeywell sizes.
Shop all Cut Carbon pre-filters →Most purifiers use one of two setups, and it's worth knowing which one you have before you buy.
A complete filter assembly — one unit with the particle-capture media and a carbon layer attached. If your purifier takes a single filter block that slides in and out, this is what you need. That's everything on this page. Replace every 6–8 months.
A separate pre-filter — a thin carbon sheet or wrap that sits in front of a main filter you replace on its own schedule. If your purifier has two distinct pieces, you may only need the pre-filter. Those are our Cut Carbon pre-filters, replaced every 90 days.
A combination filter does two jobs in one unit, using two different types of media.
The main media handles particles. Pleated filter media captures airborne debris — dust, lint, pollen, pet dander, mold spores, and smoke particles — as air passes through. The media is true HEPA-style, capturing 99.97% of airborne particles at 0.3 microns.
The activated carbon layer handles odors and gases. Carbon works by adsorption: the media is processed to be extremely porous, and odor-causing gas molecules bind to that pore surface. It's what helps reduce smells from cooking, pets, and smoke, along with VOCs. HEPA media captures particles but doesn't adsorb gases, which is why both layers are there.
The carbon layer also acts as the pre-filter. It sits on the intake side and catches larger debris first, which helps the main media stay clear and keeps air moving.
Takes seconds, no tools required.
Power off and unplug the purifier.Then, open the filter compartment.
Slide out the old filterNote its orientation — the carbon side faces the air intake. Snap a photo first if you want a reference.
Slide the new filterIn the same orientation. It's a precise fit — no trimming or forcing.
Close up, plug in, and reset the filter indicatorIf your model has one. Check your purifier's manual for the reset sequence.
While you're in there: wipe out the filter housing. Dust collects in the compartment, not just on the filter.
Then: replace every 6–8 months, sooner with heavy use or during wildfire smoke season.
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