Furnace Filters
Best 12x25x1 Furnace Filter (2026): 4 Models Side by Side
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For the best 12x25x1 furnace filter, size comes first: the top-ranked Filtrete is a 12x24x1 MERV 11 filter in a 2-pack, while the AIRx matches the 12x25x1 size with MERV 11 in a 6-pack.
Starting out? See the main guide: Best Furnace Air Filters
Top picks at a glance
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Best OverallFiltrete 12x24x1 Air Filter9.8 View on Amazon -
Most in the PackAIRx Filters 12x25x1 Furnace AC Filter MERV9.7 View on Amazon -
Also GreatSimply 12x25x1 Air Filter9.3 View on Amazon -
Also GreatFilter King 12x25x1 Air Filter MERV9.2 View on Amazon
Compare the specs
Ranked on pack size from each listing, plus how many buyers have rated it. A dash (—) means we could not confirm that figure from the listing.
| Pick | MERV rating | Pack size | Weight | Warranty |
|---|---|---|---|---|
| 1. Filtrete 12x24x1 Air Filter | MERV 11 | 2-pack | — | — |
| 2. AIRx Filters 12x25x1 Furnace AC Filter MERV | MERV 11 | 6-pack | — | — |
| 3. Simply 12x25x1 Air Filter | MERV 8 | 4-pack | — | — |
| 4. Filter King 12x25x1 Air Filter MERV | MERV 8 | 4-pack | — | — |
Filtrete 12x24x1 Air Filter
It pairs a 12x24x1 size with MERV 11, MPR 1000 and a 2-pack for 3-month changes.
- MERV rating: MERV 11
- Pack size: 2-pack
Good for
- Buyers who want MERV 11 filtration
- Buyers who want a 2-pack
Skip it if
- You want a 12x25x1 filter
- You want more than 2 filters
It captures microparticles with MERV 11 and MPR 1000 ratings, using 3-in-1 technology to pull in and trap particles. The Smart App sets 30-, 60- or 90-day reminders, and the pleated filter changes at least once every 90 days. The actual size is 11.68 by 23.68 by 0.81 inches.
AIRx Filters 12x25x1 Furnace AC Filter MERV
It pairs a 12x25x1 size with MERV 11, a 6-pack and an actual size of 11.75 by 24.75 by 0.75 inches.
- MERV rating: MERV 11
- Pack size: 6-pack, the most here
Good for
- Buyers who want a 12x25x1 size
- Buyers who want a 6-pack
Skip it if
- You want more than 6 filters
- You want a MERV rating over 11
The moisture-resistant double-wall frames stand up to 180 degrees, and the filters are made in the USA. Replace them every 60 to 90 days, or every 30 to 60 days when the system runs frequently.
Simply 12x25x1 Air Filter
It pairs a 12x25x1 size with MERV 8, a 4-pack and up to 3 months of filtration.
- MERV rating: MERV 8
- Pack size: 4-pack
Good for
- Buyers who want a 12x25x1 size
- Buyers who want a 4-pack
Skip it if
- You want more than 4 filters
- You want a MERV rating over 8
The filters fit most brands with an actual size of 11.75 by 24.75 by 0.75 inches, and they install with airflow arrows. They are made in the USA and last up to 3 months.
Filter King 12x25x1 Air Filter MERV
It pairs a 12x25x1 size with MERV 8, a 4-pack and a pleated design.
- MERV rating: MERV 8
- Pack size: 4-pack
Good for
- Buyers who want a 12x25x1 size
- Buyers who want a 4-pack
Skip it if
- You want more than 4 filters
- You want a MERV rating over 8
It captures more particles with a pleated design that does not restrict airflow, and it installs by opening, sliding and closing. The actual size is 11.5 by 24.5 by 0.75 inches, and the filters last up to 90 days. Change them every 30 to 90 days for 1-inch filters.
How to choose
Size and fit
Nominal size is not the same as actual size, so check both before you buy. The Filtrete is a 12x24x1 filter with an actual size of 11.68 by 23.68 by 0.81 inches, while the AIRx and Simply measure 11.75 by 24.75 by 0.75 inches and the Filter King measures 11.5 by 24.5 by 0.75 inches. Match the actual size to the slot in your system.
MERV and pack size
MERV tells you the rating, and pack size tells you how many filters you get. The Filtrete and AIRx carry MERV 11, while the Simply and Filter King carry MERV 8. The AIRx holds 6 filters, the Simply and Filter King hold 4 each, and the Filtrete holds 2. Pick the rating and pack count that match your change schedule.
Change timing
Change timing decides when you open the filter slot. The Filtrete changes at least once every 90 days, the AIRx every 60 to 90 days, and the Filter King every 30 to 90 days, while the Simply lasts up to 3 months. The Filtrete Smart App sets 30-, 60- or 90-day reminders to help you remember. Match the change schedule to your routine.
FAQ
Which filters fit 12x25x1 systems?
The AIRx, Simply and Filter King are 12x25x1 filters. The Filtrete is a 12x24x1 filter, so check its size against your slot.
Which filters carry MERV 11?
The Filtrete and the AIRx carry MERV 11, while the Simply and the Filter King carry MERV 8.
How many filters come in each pack?
The Filtrete holds 2, the AIRx holds 6, and the Simply and Filter King hold 4 each.
When should these filters change?
The Filtrete changes at least once every 90 days, the AIRx every 60 to 90 days, and the Filter King every 30 to 90 days, and the Simply lasts up to 3 months.
