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Replacement filter set

GermGuardian Filter B FLT4825 replacement filter

Filter B (part FLT4825) fits GermGuardian AC4300, GermGuardian AC4820, GermGuardian AC4825 and 5 more models, according to the official GermGuardian product page.

Official GermGuardian fit · checked

GermGuardian models that use Filter B FLT4825

This filter is listed for 8 models. Open a model to see its complete list of primary, optional, and specialty filters.

Before you order

What to check in a FLT4825 listing

  • The listing names part FLT4825. Similar-looking filters are not proof of fit.
  • Your purifier is one of the compatible models: GermGuardian AC4300, GermGuardian AC4820, GermGuardian AC4825 and 5 more models.
  • The pack size and pieces included match what you need. Genuine and third-party filters can differ.
  • The total price with shipping, seller feedback, and delivery estimate work for you.

Care guidance

Replacement schedule

The cited page states that FLT22CB4 carbon pre-filters can be replaced every 2 to 3 months to extend filter life; it does not state a replacement interval for FLT4825.

Usage conditions can affect service life. Follow the cited manufacturer guidance for this part.

Compare compatible options

These share at least one compatible model but may do a different job, such as a carbon pre-filter or a specialty version. Check each part page before buying.

Frequently asked questions

How often should I replace the GermGuardian Filter B (FLT4825)?

The cited page states that FLT22CB4 carbon pre-filters can be replaced every 2 to 3 months to extend filter life; it does not state a replacement interval for FLT4825.

Which GermGuardian models use the Filter B FLT4825?

According to the official GermGuardian product page, Filter B (FLT4825) fits GermGuardian AC4300, GermGuardian AC4820, GermGuardian AC4825 and 5 more models. Verify the model label on your unit before ordering.

Do aftermarket FLT4825 filters work?

Marketplace listings may be from the manufacturer or a third party. Match the exact part number FLT4825, review the listing details, and verify the model label on your unit before buying.

Official compatibility record

Manufacturer source

Official Guardian Technologies product page identifies Filter B, SKU FLT4825, as compatible with models AC4300, AC4820, AC4825, AC4850PT, AC4870, AC4880, AC4900 and CDAP4500.

Guardian Technologies GermGuardian FLT4825 - Filter B

Source compatibility checked 2026-08-29. Recheck the listing and your purifier label before ordering.