Furnace Filters
Best 16x26x5 Furnace Filter (2026): 3 Picks Compared
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For a 16x26x5 furnace filter, note the picks here are 16x25 nominal sizes, so measure your slot against the actual sizes listed for each pick. The Aerostar leads this list as a MERV 11 4-pack with an actual size of 15.75 by 24.75 by 0.75 inches. The Filtrete is a 16x25x5 nominal filter with a 2-pack and a 12-month change interval.
Starting out? See the main guide: Best Furnace Air Filters
Top picks at a glance
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Best OverallAerostar Air Filter 16x25x1 MERV 11 AC9.8 View on Amazon -
Runner-UpFiltrete 16x25x5 Air Filter9.3 View on Amazon -
Also GreatLennox X66709.2 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. Aerostar Air Filter 16x25x1 MERV 11 AC | MERV 11 | 4-pack | — | — |
| 2. Filtrete 16x25x5 Air Filter | MERV 11 | 2-pack | — | — |
| 3. Lennox X6670 | MERV 11 | — | — | — |
Aerostar Air Filter 16x25x1 MERV 11 AC
It pairs MERV 11 filtration with a 4-pack, an actual size of 15.75 by 24.75 by 0.75 inches and pleated synthetic media.
- MERV rating: MERV 11
- Pack size: 4-pack
Good for
- Buyers who want a MERV 11 4-pack for a 1-inch slot
- People who want pleated synthetic media with wire backing
Skip it if
- You want a filter thicker than 1 inch
- You want a change interval longer than 3 months
The pleated design uses a beverage board frame with wire backing, and the filter fits standard 1-inch slots. Replace it every 2 to 3 months, and the 4-pack covers repeated changes.
Filtrete 16x25x5 Air Filter
It pairs MERV 11 and MPR 1000 ratings with a 2-pack, an actual size of 15.63 by 24.74 by 4.31 inches and a 12-month change interval.
- MERV rating: MERV 11
- Pack size: 2-pack
Good for
- Buyers who want a MERV 11 filter for Lennox media air cleaners
- People who want app reminders for filter changes
Skip it if
- You want a change interval longer than 12 months
- You want a pack larger than 2 filters
It uses Filtrete 3-in-1 technology to pull in and trap particles, with MERV 11 and MPR 1000 ratings. The 2-pack fits Lennox media air cleaners, and the exact size is 15.63 by 24.74 by 4.31 inches. Change the 4-inch filter at least once every 12 months, and the Filtrete Smart App sets 90, 180 or 365-day reminders.
Lennox X6670
It pairs MERV 11 filtration with a 2-pack of fiberglass pleated filters in a 16 by 25 by 5 inch size.
- MERV rating: MERV 11
Good for
- Buyers who want an OEM Lennox filter
- People who want a fiberglass pleated filter
Skip it if
- You want a filter thicker than 5 inches
- You want a pack larger than 2 filters
It is a Lennox OEM HCF16-11 filter with MERV 11 filtration, fiberglass material and a pleated build. The size is 25 by 16 by 5 inches with a slide-in mount for residential systems. The 2-pack covers two filter changes.
How to choose
Check nominal against actual size
Nominal sizes round the numbers, so compare the actual size with your slot. The Aerostar actual size is 15.75 by 24.75 by 0.75 inches, the Filtrete is 15.63 by 24.74 by 4.31 inches and the Lennox is 25 by 16 by 5 inches. A 1-inch slot takes the Aerostar, while a 5-inch slot takes the Filtrete or the Lennox.
MERV 11 across all three
All three picks carry a MERV 11 rating, so the rating alone will not separate them. The Aerostar adds MPR 1200 and FPR 7 comparisons, while the Filtrete adds MPR 1000. Compare pack size, thickness and change interval instead: the Aerostar is a 4-pack changed every 2 to 3 months, and the Filtrete is a 2-pack changed at least once every 12 months.
Fit, thickness and replacement
Thickness decides fit: the Aerostar at 0.75 inches fits a 1-inch slot, while the Filtrete at 4.31 inches and the Lennox at 5 inches fit deeper slots. Pleated construction runs through all three picks, and the Aerostar uses a beverage board frame with wire backing. Set a reminder for the change interval, like the Filtrete Smart App with 90, 180 or 365-day reminders.
FAQ
What actual size is the Aerostar filter?
The Aerostar actual size is 15.75 by 24.75 by 0.75 inches, a 1-inch nominal filter in a MERV 11 4-pack.
Which pick fits a Lennox media air cleaner?
The Filtrete is designed to fit Lennox brand media air cleaners, with MERV 11 and MPR 1000 ratings in a 2-pack.
How do I know when to change the filter?
Change the Aerostar every 2 to 3 months and the Filtrete at least once every 12 months. The Filtrete Smart App sets 90, 180 or 365-day reminders.
Are these filters 16x26x5?
No. The picks here are 16x25 nominal sizes: the Aerostar is 16x25x1, and the Filtrete and Lennox are 16x25x5. Check the actual size against your slot.
