Furnace Filters
Best 25x25x1 Furnace Filter (2026): 5 Models Side by Side
As an Amazon Associate we earn from qualifying purchases. Specs below come from each product's Amazon listing; we do not test products in person.
For the best 25x25x1 furnace filter, the Filtrete leads this list: it pairs MERV 11 with MPR 1000 in a pleated 4-pack, with app reminders for the 90-day change. If you want more filters per box, the 12-pack Simply is the other pick to check, and the True Blue is another MERV 11 pick in a 4-pack.
Starting out? See the main guide: Best Furnace Air Filters
Top picks at a glance
-
Best OverallFiltrete 25x25x1 AC Furnace Air Filter9.8 View on Amazon -
Most in the PackSimply 25x25x1 Air Filter9.6 View on Amazon -
Also GreatTrue Blue Allergen 25x25x1 Air Filter9.6 View on Amazon -
Also GreatFilter King 25x25x1 Air Filter MERV9.6 View on Amazon -
Also GreatNordic Pure 25x25x1 Pleated MERV 8 Air9.2 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 25x25x1 AC Furnace Air Filter | MERV 11 | 4-pack | — | — |
| 2. Simply 25x25x1 Air Filter | MERV 8 | 12-pack | — | — |
| 3. True Blue Allergen 25x25x1 Air Filter | MERV 11 | 4-pack | — | — |
| 4. Filter King 25x25x1 Air Filter MERV | MERV 8 | 6-pack | — | — |
| 5. Nordic Pure 25x25x1 Pleated MERV 8 Air | MERV 8 | 6-pack | — | — |
Filtrete 25x25x1 AC Furnace Air Filter
It pairs MERV 11 with MPR 1000 in a pleated 4-pack, with app reminders for the 90-day change.
- MERV rating: MERV 11
- Pack size: 4-pack
Good for
- Buyers who want MERV 11 filtration
- Buyers who want a 4-pack with app reminders
Skip it if
- You want a pack larger than 4 filters
- You want MERV 8 filtration
The pleated filter carries MERV 11 with MPR 1000 and uses electrostatic cleaning to pull in and trap particles from air passing through it. The 4-pack holds four filters, with a change at least once every 90 days. The Filtrete Smart App sets 30-, 60- or 90-day reminders, and the filter fits furnaces, air conditioners and heating systems.
Simply 25x25x1 Air Filter
It pairs MERV 8 with a 12-pack and pleated media, with up to 3 months of filtration per filter.
- MERV rating: MERV 8
- Pack size: 12-pack, the most here
Good for
- Buyers who want a 12-pack of filters
- Buyers who want MERV 8 filtration
Skip it if
- You want MERV 11 filtration
- You want a pack smaller than 12 filters
The pleated filter carries MERV 8 in a 12-pack, with up to 3 months of filtration per filter. The filters use American components, with a rectangular shape in cardboard and paper materials.
True Blue Allergen 25x25x1 Air Filter
It pairs MERV 11 with electrostatic charged media in a 4-pack, changed every 4 months.
- MERV rating: MERV 11
- Pack size: 4-pack
Good for
- Buyers who want MERV 11 filtration
- Buyers who want filters made in the USA
Skip it if
- You want MERV 8 filtration
- You want a change interval longer than 4 months
The pleated filter carries MERV 11 in a 4-pack, with electrostatic charged media that attracts and traps smaller particles. Change the filter at least every 4 months, and the filters are made in the USA.
Filter King 25x25x1 Air Filter MERV
It pairs MERV 8 with a pleated 6-pack and slide-in installation, lasting up to 90 days.
- MERV rating: MERV 8
- Pack size: 6-pack
Good for
- Buyers who want a 6-pack of filters
- Buyers who want slide-in installation
Skip it if
- You want MERV 11 filtration
- You want a pack larger than 6 filters
The pleated filter carries MERV 8 in a 6-pack, with an actual size of 24.5 by 24.5 by 0.75 inches. The pleated design captures more particles without impacting air flow, and the filter slides in for a fast change. It lasts up to 90 days, with a change every 30 to 90 days for 1-inch filters.
Nordic Pure 25x25x1 Pleated MERV 8 Air
It pairs MERV 8, equal to MPR 800, with electrostatically charged pleated media in a 6-pack.
- MERV rating: MERV 8
- Pack size: 6-pack
Good for
- Buyers who want MERV 8 filtration
- Buyers who want filters made in the USA
Skip it if
- You want MERV 11 filtration
- You want a pack larger than 6 filters
The pleated filter carries MERV 8, equal to MPR 800, in a 6-pack, with an actual size of 24.5 by 24.5 by 0.75 inches. The filters are made in the USA.
How to choose
MERV and MPR numbers
MERV and MPR describe how a filter captures particles, with higher numbers for finer capture. The Filtrete and True Blue carry MERV 11, while the Simply, Filter King and Nordic Pure carry MERV 8. The Filtrete adds MPR 1000, and the Nordic Pure states MERV 8 equal to MPR 800. Match the number to the particles you want captured, and check the size before you order.
Pack size and change interval
Pack size decides how many changes one box covers. The Simply holds 12 filters, the Filter King and Nordic Pure hold 6 each, and the Filtrete and True Blue hold 4 each. Change intervals differ too: the Filtrete and Filter King run to 90 days, the True Blue runs to 4 months, and the Simply runs up to 3 months. Count your changes per year before you pick a pack size.
Fit and installation
Nominal size is 25 by 25 by 1 across this guide, but some actual sizes run slightly smaller, so measure your current filter before you order. The Filtrete actual size is 24.69 by 24.69 by 0.81 inches, and the Filter King and Nordic Pure actual size is 24.5 by 24.5 by 0.75 inches. The Filter King slides in for a fast change, and the True Blue and Nordic Pure fit air conditioners and furnaces.
FAQ
What MERV numbers do these filters carry?
The Filtrete and True Blue carry MERV 11, and the Simply, Filter King and Nordic Pure carry MERV 8. The Filtrete adds MPR 1000, and the Nordic Pure states MERV 8 equal to MPR 800.
How many filters come in each pack?
The Simply holds 12 filters, the Filter King and Nordic Pure hold 6 each, and the Filtrete and True Blue hold 4 each.
When should I change these filters?
The Filtrete needs a change at least once every 90 days, the Filter King lasts up to 90 days, the True Blue needs a change at least every 4 months, and the Simply runs up to 3 months.
Do these filters fit furnaces and air conditioners?
The Filtrete fits furnaces, air conditioners and heating systems. The Simply, True Blue, Filter King and Nordic Pure fit air conditioners and furnaces, and the Simply and True Blue also fit heat pumps.
