Furnace Filters
Best 24x24 AC Filter (2026): 4 Models Side by Side
As an Amazon Associate I earn from qualifying purchases. Specs below come from each product's Amazon listing; we do not test products in person.
For a 24x24x1 slot, the Simply 24x24x1 leads: MERV 8 pleated filtration in a 6-pack with an actual size of 23.75 by 23.75 by 0.75 inches and filtration lasting up to 3 months. The Filtrete runner-up steps up to MERV 13 and MPR 1900 for buyers who want a higher rating in a 2-pack.
Starting out? See the main guide: Best Furnace Air Filters
Top picks at a glance
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Best OverallSimply 24x24x1 Air Filter9.8 View on Amazon -
Runner-UpFiltrete 24x24x1 Air Filter9.6 View on Amazon -
Also GreatFilter King 24x24x1 Air Filter MERV9.6 View on Amazon -
Also GreatFlanders E-Z Flow Air Filter9.2 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. Simply 24x24x1 Air Filter | MERV 8 | 6-pack | — | — |
| 2. Filtrete 24x24x1 Air Filter | MERV 13 | 2-pack | — | — |
| 3. Filter King 24x24x1 Air Filter MERV | MERV 8 | 12-pack | — | — |
| 4. Flanders E-Z Flow Air Filter | MERV 4 | — | — | — |
Simply 24x24x1 Air Filter
MERV 8 pleated filtration in a 6-pack, with an actual size of 23.75 by 23.75 by 0.75 inches and up to 3 months of filtration.
- MERV rating: MERV 8
- Pack size: 6-pack
Good for
- Owners of 24x24x1 slots who want a 6-pack
- Buyers who want MERV 8 pleated filters
Skip it if
- You need a MERV rating above 8
- You need more than 6 filters per pack
It measures 24 by 24 by 1 inches, with an actual size of 23.75 by 23.75 by 0.75 inches, and it uses pleated construction. It traps 90% of airborne particles and lasts up to 3 months before replacement. It is made in the USA from 100% American components, including recycled materials.
Filtrete 24x24x1 Air Filter
MERV 13 and MPR 1900 filtration in a 2-pack, capturing 24% more microparticles than MERV 13 requirements at 0.3 to 1.0 microns.
- MERV rating: MERV 13
- Pack size: 2-pack
Good for
- Buyers who want MERV 13 and MPR 1900 filtration
- Owners who want app reminders for filter changes
Skip it if
- You need more than 2 filters per pack
- You need a change interval past 90 days
It uses Filtrete 3-in-1 technology to pull in and trap particles, with MERV 13 and MPR 1900 ratings. It captures 24% more microparticles than MERV 13 requirements, at 0.3 to 1.0 microns in size. Change it at least once every 90 days, and the Filtrete Smart App sets 30-, 60- or 90-day reminders.
Filter King 24x24x1 Air Filter MERV
MERV 8 pleated filtration in a 12-pack, with an actual size of 23.5 by 23.5 by .75 inches and up to 90 days before replacement.
- MERV rating: MERV 8
- Pack size: 12-pack
Good for
- Buyers who want a 12-pack of MERV 8 filters
- Owners who change filters every 30 to 90 days
Skip it if
- You need a MERV rating above 8
- You need a pack smaller than 12 filters
It is a MERV 8 pleated filter in a 12-pack, sized 24 by 24 by 1 inches with an actual size of 23.5 by 23.5 by .75 inches. It lasts up to 90 days before replacement, and the maker recommends changing 1 inch filters every 30 to 90 days. Installation is open, slide and close.
Flanders E-Z Flow Air Filter
MERV 4 filtration in a pack of 12, with a chipboard design and a metal media retainer for furnace and central air units.
- MERV rating: MERV 4
Good for
- Buyers who want a 12-pack of MERV 4 filters
- Owners of furnace and central air units
Skip it if
- You need a MERV rating above 4
- You need fewer than 12 filters per pack
It is a MERV 4 filter in a pack of 12, sized 24 by 24 by 1 inches for furnace and central air units. A continuous chipboard design guards against corner separation, and a one-sided metal media retainer adds strength.
How to choose
Match the actual size to your slot
All four picks carry the nominal size 24 by 24 by 1 inches, but actual sizes differ: 23.75 by 23.75 by 0.75 inches for the Simply, 23.81 by 23.81 by 0.78 inches for the Filtrete, and 23.5 by 23.5 by .75 inches for the Filter King. Measure the slot before ordering, and compare the actual size with the opening.
Compare MERV ratings, not just pack size
MERV ratings here run from MERV 4 for the Flanders to MERV 13 for the Filtrete, with two picks at MERV 8. A higher MERV rating captures smaller particles: the Filtrete captures 24% more microparticles than MERV 13 requirements at 0.3 to 1.0 microns. Pack size is separate: 6 for the Simply, 2 for the Filtrete, and 12 for the Filter King and the Flanders.
Set a change schedule
Change intervals here run up to 3 months for the Simply, at least once every 90 days for the Filtrete, and up to 90 days for the Filter King, with a 30 to 90 day recommendation for 1 inch filters. The Filtrete Smart App sets 30-, 60- or 90-day reminders. Follow the airflow arrows when inserting a filter into a slot or return grille.
FAQ
What does MERV mean on a furnace filter?
MERV rates how well a filter captures particles, with higher numbers for finer capture. Here the Flanders is MERV 4, two picks are MERV 8, and the Filtrete is MERV 13 with MPR 1900.
When should I change a 24x24x1 filter?
The Simply lasts up to 3 months, the Filtrete changes at least once every 90 days, and the Filter King lasts up to 90 days. The Filtrete Smart App sets 30-, 60- or 90-day reminders.
Do all four filters fit the same slot?
All four carry the nominal size 24 by 24 by 1 inches, but actual sizes differ, so measure the slot first. The Simply measures 23.75 by 23.75 by 0.75 inches and the Filtrete measures 23.81 by 23.81 by 0.78 inches.
How many filters come in each pack?
The Filter King and the Flanders come in packs of 12, the Simply comes in a 6-pack, and the Filtrete comes in a 2-pack.
