Grills

AC & Furnace Air Filters by Size

AC return and furnace filters in more than 30 sizes, from $2.99 fiberglass to MERV 13 allergen filters and 4-inch media cabinet filters. Find your size, choose a rating, and pick it up in Cape Coral or Fort Myers.

74 items in stock

10x10 to 25x25

MERV 2 to MERV 13

Cape Coral & Fort Myers

Free pickup in ~2 hours

Short answer

Find the size printed on the edge of the filter you have now, for example 16x25x1, and buy that exact size. It is a nominal size, so do not use a tape measure on the filter slot. Then pick a rating. Fiberglass (MERV 2) is the cheapest and catches the dust and lint that coat the AC coil. Pleated MERV 8 also traps pollen, mold spores and pet dander, and it is the right choice for most homes. MERV 11–13 is for allergies and asthma, as long as your system can move air through it. In Southwest Florida the AC runs most of the year, so change a 1-inch filter every month (every 1–2 months for pleated). A 4-inch media filter lasts 3–6 months.

Find Your Filter Size

Pick the size printed on the edge of your current filter (width x height x depth). You will see every rating we carry in that size, cheapest first.

1-inch filters

10x10x1

10x20x1

10x24x1

10x25x1

12x12x1

12x18x1

12x20x1

12x24x1

12x25x1

12x30x1

12x36x1

14x14x1

14x18x1

14x20x1

14x24x1

14x25x1

14x30x1

15x20x1

16x16x1

16x20x1

16x24x1

16x25x1

16x30x1

18x18x1

18x20x1

18x24x1

18x25x1

18x30x1

20x20x1

20x24x1

20x25x1

20x30x1

24x24x1

24x30x1

25x25x1

4-inch filters

16x20x4

16x25x4

20x20x4

20x25x4

24x24x4

Size not listed? Bring the old filter to either store and we will match it, or see the trimmable pad in the fiberglass section below.

Good, Better, Best — Shown in 16x25x1, the Most Common Size

The same filter slot, five ways. Each step up catches smaller particles and costs more per change. Most homes are best served by the MERV 8 in the middle; allergy households should look at the last two. Every size on this page has the same ladder in the size finder above.

True Blue 16 In. x 25 In. x 1 In. Merv 2 Fiberglass Furnace Filter (116251)

$2.99

Item #430073

16x25x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

Purafilter 16 In. x 25 In. x 1 In. MERV 5 Polyfiber Furnace Filter (PFBP1625)

$4.99

Item #450580

16x25x1 polyfiber MERV 5. The cheapest step up from fiberglass: it catches noticeably more dust and still breathes easily, which suits older air handlers.

Do it Best 16 In. x 25 In. x 1 In. MERV 8 Furnace Filter (DB1-1625-8-12)

$6.79

Item #474282

16x25x1 pleated MERV 8. It traps pollen, mold spores and pet dander as well as dust. This is the level most HVAC techs recommend for a typical Florida home. Change it every 1–2 months in summer.

Filtrete 16 In. x 25 In. x 1 In. 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11 (9801-4)

$14.99

Item #428116

16x25x1 Filtrete 1000 MPR (MERV 11) for allergy households. It catches fine dust, smoke and pet dander a MERV 8 lets through. Change it monthly in peak season so airflow stays up.

Filtrete 16 In. x 25 In. x 1 In. 1900 MPR Premium Allergen, Bacteria & Virus Furnace Filter, MERV 13 (UA01-4)

$25.99

Item #493781

16x25x1 MERV 13, the highest rating most home systems can run. It catches bacteria- and smoke-size particles. Change it on schedule, because a loaded MERV 13 chokes airflow faster than anything else here.

Budget Fiberglass Filters (MERV 2) — True Blue

The flat blue spun-fiberglass filter is the least expensive way to protect your air conditioner. It is designed to stop the lint, hair and household dust that would otherwise pack onto the evaporator coil and blower. It does little for pollen or dander. It also restricts airflow less than anything else here, which makes it a safe choice for older or undersized systems. At about three dollars each, changing it monthly is easy. The trimmable pad at the end of this section is for return grilles that do not take a standard framed size.

True Blue 10 In. x 10 In. x 1 In. Merv 2 Fiberglass Furnace Filter (110101)

$2.99

Item #405752

10x10x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 10 In. x 20 In. x 1 In. Merv 2 Fiberglass Furnace Filter (110201)

$3.49

Item #430153

10x20x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 10 In. x 24 In. x 1 In. Merv 2 Fiberglass Furnace Filter (110241)

$6.49

Item #405744

10x24x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 10 In. x 25 In. x 1 In. Merv 2 Fiberglass Furnace Filter (110251)

$6.49

Item #405841

10x25x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 12 In. x 12 In. x 1 In. MERV 2 Fiberglass Furnace Filter (112121)

$7.79

Item #484413

12x12x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 12 In. x 18 In. x 1 In. Merv 2 Fiberglass Furnace Filter (112181)

$3.49

Item #405751

12x18x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 12 In. x 20 In. x 1 In. Merv 2 Fiberglass Furnace Filter (112201)

$2.99

Item #430135

12x20x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 12 In. x 24 In. x 1 In. Merv 2 Fiberglass Furnace Filter (112241)

$8.29

Item #430126

12x24x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 12 In. x 25 In. x 1 In. Merv 2 Fiberglass Furnace Filter (112251)

$6.49

Item #411432

12x25x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 12 In. x 30 In. x 1 In. Merv 2 Fiberglass Furnace Filter (112301)

$6.29

Item #499762

12x30x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 14 In. x 14 In. x 1 In. Merv 2 Fiberglass Furnace Filter (114141)

$2.99

Item #467569

14x14x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 14 In. x 18 In. x 1 In. Merv 2 Fiberglass Furnace Filter (114181)

$3.49

Item #403124

14x18x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 14 In. x 20 In. x 1 In. Merv 2 Fiberglass Furnace Filter (114201)

$2.99

Item #430117

14x20x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 14 In. x 24 In. x 1 In. Merv 2 Fiberglass Furnace Filter (114241)

$2.99

Item #404888

14x24x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 14 In. x 25 In. x 1 In. Merv 2 Fiberglass Furnace Filter (114251)

$6.99

Item #430108

14x25x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 14 In. x 30 In. x 1 In. Merv 2 Fiberglass Furnace Filter (114301)

$6.99

Item #488919

14x30x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 15 In. x 20 In. x 1 In. Merv 2 Fiberglass Furnace Filter (115201)

$5.79

Item #430091

15x20x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 16 In. x 16 In. x 1 In. Merv 2 Fiberglass Furnace Filter (116161)

$5.79

Item #406563

16x16x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 16 In. x 20 In. x 1 In. Merv 2 Fiberglass Furnace Filter (116201)

$2.99

Item #430082

16x20x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 16 In. x 24 In. x 1 In. Merv 2 Fiberglass Furnace Filter (116241)

$6.99

Item #405620

16x24x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 16 In. x 25 In. x 1 In. Merv 2 Fiberglass Furnace Filter (116251)

$2.99

Item #430073

16x25x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 16 In. x 30 In. x 1 In. Merv 2 Fiberglass Furnace Filter (116301)

$3.99

Item #405787

16x30x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 18 In. x 18 In. x 1 In. Merv 2 Fiberglass Furnace Filter (118181)

$2.99

Item #493418

18x18x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 18 In. x 20 In. x 1 In. Merv 2 Fiberglass Furnace Filter (118201)

$6.99

Item #491419

18x20x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 18 In. x 24 In. x 1 In. Merv 2 Fiberglass Furnace Filter (118241)

$2.99

Item #491826

18x24x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 18 In. x 25 In. x 1 In. Merv 2 Fiberglass Furnace Filter (118251)

$5.79

Item #430055

18x25x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 18 In. x 30 In. x 1 In. Merv 2 Fiberglass Furnace Filter (118301)

$6.49

Item #499436

18x30x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 20 In. x 20 In. x 1 In. Merv 2 Fiberglass Furnace Filter (120201)

$2.99

Item #430046

20x20x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 20 In. x 24 In. x 1 In. MERV 2 Fiberglass Furnace Filter (120241)

$2.99

Item #484659

20x24x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 20 In. x 25 In. x 1 In. Merv 2 Fiberglass Furnace Filter (120251)

$2.99

Item #430037

20x25x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 24 In. x 24 In. x 1 In. Merv 2 Fiberglass Furnace Filter (124241)

$2.99

Item #405591

24x24x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 24 In. x 30 In. x 1 In. Merv 2 Fiberglass Furnace Filter (124301)

$7.79

Item #496842

24x30x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 25 In. x 25 In. x 1 In. Merv 2 Fiberglass Furnace Filter (125251)

$7.49

Item #405906

25x25x1 spun-fiberglass filter. It stops the lint and dust that coat an AC coil, lets air through easily, and costs little enough to change every month while the AC runs.

True Blue 20 In. x 30 In. x 1 In. MERV 4 Trimmable Air Filter (0120301)

$21.49

Item #437425

Cut-to-fit MERV 4 pad for odd-size return grilles and window units nobody makes a framed filter for — measure the opening, trim with scissors, and drop it in.

Pleated Filters (MERV 5–8) — The Everyday Upgrade

Pleating packs much more filter media into the same 1-inch frame, so these capture far more than fiberglass without choking the system. MERV 5 polyfiber is the cheapest step up. MERV 8 is the level most HVAC technicians recommend for a typical house: it traps pollen, mold spores, pet dander and fine dust. Florida humidity and year-round AC make mold spores a real concern here. In summer, change these every 1–2 months.

Purafilter 12 In. x 24 In. x 1 In. Merv 5 Polyfiber Furnace Filter (PFBP1224)

$4.99

Item #425341

12x24x1 polyfiber MERV 5. The cheapest step up from fiberglass: it catches noticeably more dust and still breathes easily, which suits older air handlers.

Purafilter 14 In. x 20 In. x 1 In. MERV 5 Polyfiber Furnace Filter (PFBP1420)

$4.99

Item #426777

14x20x1 polyfiber MERV 5. The cheapest step up from fiberglass: it catches noticeably more dust and still breathes easily, which suits older air handlers.

Purafilter 14 In. x 25 In. x 1 In. MERV 5 Polyfiber Furnace Filter (PFBP1425)

$4.99

Item #443720

14x25x1 polyfiber MERV 5. The cheapest step up from fiberglass: it catches noticeably more dust and still breathes easily, which suits older air handlers.

Purafilter 16 In. x 20 In. x 1 In. MERV 5 Polyfiber Furnace Filter (PFBP1620)

$4.99

Item #449702

16x20x1 polyfiber MERV 5. The cheapest step up from fiberglass: it catches noticeably more dust and still breathes easily, which suits older air handlers.

Purafilter 16 In. x 25 In. x 1 In. MERV 5 Polyfiber Furnace Filter (PFBP1625)

$4.99

Item #450580

16x25x1 polyfiber MERV 5. The cheapest step up from fiberglass: it catches noticeably more dust and still breathes easily, which suits older air handlers.

Purafilter 20 In. x 20 In. x 1 In. MERV 5 Polyfiber Furnace Filter (PFBP2020)

$4.99

Item #459698

20x20x1 polyfiber MERV 5. The cheapest step up from fiberglass: it catches noticeably more dust and still breathes easily, which suits older air handlers.

Purafilter 20 In. x 25 In. x 1 In. MERV 5 Polyfiber Furnace Filter (PFBP2025)

$4.99

Item #463556

20x25x1 polyfiber MERV 5. The cheapest step up from fiberglass: it catches noticeably more dust and still breathes easily, which suits older air handlers.

Purafilter 20 In. x 30 In. x 1 In. MERV 5 Polyfiber Furnace Filter (PFBP2030)

$5.29

Item #469105

20x30x1 polyfiber MERV 5. The cheapest step up from fiberglass: it catches noticeably more dust and still breathes easily, which suits older air handlers.

True Blue 12 In. x 36 In. x 1 In. Basic Protection MERV 7 Furnace Filter (212361)

$6.99

Item #404965

The long, narrow 12x36x1 is a common condo and lanai-closet return size. This pleated MERV 7 is the only framed one we carry in it, and it catches far more dust than fiberglass.

BestAir 12 In. x 24 In. x 1 In. MERV 8 Furnace Filter (DB1-1224-8-12)

$6.79

Item #448001

12x24x1 pleated MERV 8. It traps pollen, mold spores and pet dander as well as dust. This is the level most HVAC techs recommend for a typical Florida home. Change it every 1–2 months in summer.

BestAir 14 In. x 20 In. x 1 In. MERV 8 Furnace Filter (DB1-1420-8-12)

$6.79

Item #424536

14x20x1 pleated MERV 8. It traps pollen, mold spores and pet dander as well as dust. This is the level most HVAC techs recommend for a typical Florida home. Change it every 1–2 months in summer.

BestAIr 14 In. x 25 In. x 1 In. MERV 8 Furnace Filter (DB1-1425-8-12)

$6.79

Item #424528

14x25x1 pleated MERV 8. It traps pollen, mold spores and pet dander as well as dust. This is the level most HVAC techs recommend for a typical Florida home. Change it every 1–2 months in summer.

BestAir 16 In. x 20 In. x 1 In. MERV 8 Furnace Filter (DB1-1620-8-12)

$6.79

Item #474274

16x20x1 pleated MERV 8. It traps pollen, mold spores and pet dander as well as dust. This is the level most HVAC techs recommend for a typical Florida home. Change it every 1–2 months in summer.

Do it Best 16 In. x 25 In. x 1 In. MERV 8 Furnace Filter (DB1-1625-8-12)

$6.79

Item #474282

16x25x1 pleated MERV 8. It traps pollen, mold spores and pet dander as well as dust. This is the level most HVAC techs recommend for a typical Florida home. Change it every 1–2 months in summer.

BestAir 20 In. x 20 In. x 1 In. MERV 8 Furnace Filter (DB1-2020-8-12)

$6.79

Item #474290

20x20x1 pleated MERV 8. It traps pollen, mold spores and pet dander as well as dust. This is the level most HVAC techs recommend for a typical Florida home. Change it every 1–2 months in summer.

BestAir 20 In. x 25 In. x 1 In. MERV 8 Furnace Filter (DB1-2025-8-12)

$6.79

Item #474304

20x25x1 pleated MERV 8. It traps pollen, mold spores and pet dander as well as dust. This is the level most HVAC techs recommend for a typical Florida home. Change it every 1–2 months in summer.

BestAir 20 In. x 30 In. x 1 In. MERV 8 Furnace Filter (DB1-2030-8-12)

$6.79

Item #448044

20x30x1 pleated MERV 8. It traps pollen, mold spores and pet dander as well as dust. This is the level most HVAC techs recommend for a typical Florida home. Change it every 1–2 months in summer.

Allergen Filters (MERV 11–13) — Filtrete

For allergy or asthma households, and for smoke, pets and construction dust. MERV 11 (Filtrete 1000 MPR) catches much finer particles than MERV 8, and MERV 13 (Filtrete 1900 MPR) is the highest rating most residential systems are built to handle. The trade-off is airflow: a dense filter loads up faster and restricts air more as it fills. Change these on schedule, and if the air handler gets louder or rooms stop cooling, step back down to MERV 8.

Filtrete 12 In. x 24 In. x 1 In. 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11 (9820-4)

$14.99

Item #439339

12x24x1 Filtrete 1000 MPR (MERV 11) for allergy households. It catches fine dust, smoke and pet dander a MERV 8 lets through. Change it monthly in peak season so airflow stays up.

Filtrete 14 In. x 20 In. x 1 In. 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11 (9805-4)

$14.99

Item #428159

14x20x1 Filtrete 1000 MPR (MERV 11) for allergy households. It catches fine dust, smoke and pet dander a MERV 8 lets through. Change it monthly in peak season so airflow stays up.

Filtrete 14 In. x 25 In. x 1 In. 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11 (9804-4)

$14.99

Item #428140

14x25x1 Filtrete 1000 MPR (MERV 11) for allergy households. It catches fine dust, smoke and pet dander a MERV 8 lets through. Change it monthly in peak season so airflow stays up.

Filtrete 16 In. x 20 In. x 1 In. 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11 (9800-4)

$14.99

Item #428108

16x20x1 Filtrete 1000 MPR (MERV 11) for allergy households. It catches fine dust, smoke and pet dander a MERV 8 lets through. Change it monthly in peak season so airflow stays up.

Filtrete 16 In. x 25 In. x 1 In. 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11 (9801-4)

$14.99

Item #428116

16x25x1 Filtrete 1000 MPR (MERV 11) for allergy households. It catches fine dust, smoke and pet dander a MERV 8 lets through. Change it monthly in peak season so airflow stays up.

Filtrete 20 In. x 20 In. x 1 In. 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11 (9802-4)

$14.99

Item #428124

20x20x1 Filtrete 1000 MPR (MERV 11) for allergy households. It catches fine dust, smoke and pet dander a MERV 8 lets through. Change it monthly in peak season so airflow stays up.

Filtrete 20 In. x 25 In. x 1 In. 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11 (9803-4)

$14.99

Item #428132

20x25x1 Filtrete 1000 MPR (MERV 11) for allergy households. It catches fine dust, smoke and pet dander a MERV 8 lets through. Change it monthly in peak season so airflow stays up.

Filtrete 20 In. x 30 In. x 1 In. 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11 (9822-4)

$14.99

Item #479942

20x30x1 Filtrete 1000 MPR (MERV 11) for allergy households. It catches fine dust, smoke and pet dander a MERV 8 lets through. Change it monthly in peak season so airflow stays up.

Filtrete 16 In. x 20 In. x 1 In. 1900 MPR Premium Allergen, Bacteria & Virus Furnace Filter, MERV 13 (UA00-4)

$25.99

Item #491379

16x20x1 MERV 13, the highest rating most home systems can run. It catches bacteria- and smoke-size particles. Change it on schedule, because a loaded MERV 13 chokes airflow faster than anything else here.

Filtrete 16 In. x 25 In. x 1 In. 1900 MPR Premium Allergen, Bacteria & Virus Furnace Filter, MERV 13 (UA01-4)

$25.99

Item #493781

Filtrete 20 In. x 20 In. x 1 In. 1900 MPR Premium Allergen, Bacteria & Virus Furnace Filter, MERV 13 (UA02-4)

$21.55

Item #495238

20x20x1 MERV 13, the highest rating most home systems can run. It catches bacteria- and smoke-size particles. Change it on schedule, because a loaded MERV 13 chokes airflow faster than anything else here.

Filtrete 20 In. x 25 In. x 1 In. 1900 MPR Premium Allergen, Bacteria & Virus Furnace Filter, MERV 13 (UA03-4)

$25.99

Item #499466

20x25x1 MERV 13, the highest rating most home systems can run. It catches bacteria- and smoke-size particles. Change it on schedule, because a loaded MERV 13 chokes airflow faster than anything else here.

4-Inch Deep-Pleat Media Filters

If your filter lives in a 4 to 5-inch cabinet next to the air handler rather than behind a ceiling or wall grille, it takes a deep-pleat media filter. Four inches of media holds several times the dirt of a 1-inch filter at the same rating, so a MERV 11 media filter can outlast three or four 1-inch ones. Match the brand style printed on your cabinet door: the Honeywell/Lennox-style (HW) filters and the standard 4-inch pleats are not interchangeable in every housing.

BestAir 16 In. x 20 In. x 4 In. MERV 8 Pleated Furnace Filter (BA4-1620-8)

$14.99

Item #439237

16x20x4 deep-pleat MERV 8 for standard 4-inch media cabinets. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

BestAir 16 In. x 25 In. x 4 In. MERV 8 Pleated Furnace Filter (BA4-1625-8)

$14.99

Item #469271

16x25x4 deep-pleat MERV 8 for standard 4-inch media cabinets. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

BestAir 20 In. x 20 In. x 4 In. Pleated Furnace Filter, MERV 8 (BA4-2020-8)

$15.49

Item #441949

20x20x4 deep-pleat MERV 8 for standard 4-inch media cabinets. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

BestAir 20 In. x 25 In. x 4 In. MERV 8 Pleated Furnace Filter (BA4-2025-8)

$16.49

Item #481047

20x25x4 deep-pleat MERV 8 for standard 4-inch media cabinets. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

BestAir 24 In. x 24 In. x 4 In. MERV 8 Pleated Furnace Filter (BA4-2424-8)

$15.99

Item #487846

24x24x4 deep-pleat MERV 8 for standard 4-inch media cabinets. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

BestAir 16 In. x 25 In. x 4 In. Honeywell MERV 11 Deep Pleat Furnace Filter (HW1625-11R)

$29.99

Item #468930

16x25x4 deep-pleat MERV 11 for Honeywell/Lennox-style media cabinets. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

BestAir 20 In. x 25 In. x 4 In. Honeywell MERV 11 Deep Pleat Furnace Filter (HW2025-11R)

$31.99

Item #472149

20x25x4 deep-pleat MERV 11 for Honeywell/Lennox-style media cabinets. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

Filtrete 16 In. x 25 In. x 4 In. 1000 MPR Allergen Defense Deep Pleat Furnace Filter, MERV 11 (NADP01-4IN-4)

$27.99

Item #404714

16x25x4 deep-pleat MERV 11 for Filtrete deep-pleat housings. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

Filtrete 20 In. x 25 In. x 4 In. 1000 MPR Allergen Defense Deep Pleat Furnace Filter, MERV 11 (NADP03-4IN-4)

$27.99

Item #404736

20x25x4 deep-pleat MERV 11 for Filtrete deep-pleat housings. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

BestAir 16 In. x 25 In. x 4 In. Honeywell MERV 13 Deep Pleat Furnace Filter (HW1625-13R)

$44.99

Item #474985

16x25x4 deep-pleat MERV 13 for Honeywell/Lennox-style media cabinets. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

BestAir 20 In. x 25 In. x 4 In. Honeywell MERV 13 Deep Pleat Furnace Filter (HW2025-13R)

$46.99

Item #481264

20x25x4 deep-pleat MERV 13 for Honeywell/Lennox-style media cabinets. Four inches of media holds far more dirt than a 1-inch filter, so it typically lasts 3–6 months between changes.

Looking for something not on this list? Both stores carry far more than we can put on one page — browse all Filtrete filters, all BestAir filters and how Auto Restock works. Not sure of your size? Bring the old filter to either store and we will match it.

How to Change an AC Filter

Changing the filter takes about two minutes and is the cheapest maintenance your AC gets. A clogged filter makes the system work harder, raises the power bill, and can freeze the coil on a humid day.

Turn the system off at the thermostat

With the blower off, the dust on the old filter will not be pulled into the return while you swap it, and a loose filter will not be sucked against the coil. Most homes here have the filter behind a ceiling or wall return grille, or in a slot at the air handler in a closet or the garage.

Read the size on the old filter

The size is printed on the edge of the frame as width x height x depth, for example 16x25x1. That is the nominal size, and the actual filter is a little smaller, so buy what is printed rather than what you measure. If the old filter has no label, measure the slot and round up to the nearest inch.

Match the airflow arrow

Every framed filter has an arrow on the edge. It points in the direction the air moves, which is toward the air handler and away from the return grille. For a ceiling return, that means the arrow points up into the ceiling. A filter installed backwards filters poorly and can collapse.

Slide it in and close up

The filter should sit flat with no gaps around the edges, because air takes the easiest path and unfiltered air skipping around a loose filter defeats the point. Close the grille or cabinet door, latch it, and turn the system back on.

Write the date on it and set a reminder

Mark the install date on the frame with a marker. In Southwest Florida, change 1-inch fiberglass monthly, pleated MERV 8 every 1–2 months, and 4-inch media every 3–6 months. Shorten that with pets, construction or heavy summer use. Auto Restock can ship your size on that schedule.

Air Filter Questions, Answered

Use the size printed on the edge of the filter you are replacing, written as width x height x depth, for example 16x25x1 or 20x20x1. That number is a nominal size, and the real filter is usually about half an inch smaller, so do not buy by tape-measuring the old filter. If there is no label, measure the slot or grille opening and round up to the nearest whole inch. Some homes have more than one return, so check each one.

More often than the package says. Those intervals assume a northern home that runs heat or AC part of the year, but in Southwest Florida the AC runs most of the year and many days around the clock. Plan on monthly for 1-inch fiberglass, every 1–2 months for 1-inch pleated, and every 3–6 months for 4-inch media filters. Change sooner with pets, smokers, renovation dust, or a filter that looks gray.

MERV measures how well a filter captures particles, and higher means smaller particles. MERV 2 fiberglass stops lint, hair and large dust, mainly to protect the equipment. MERV 8 adds pollen, mold spores and pet dander, and it is the usual recommendation for a home. MERV 11 catches finer dust and some smoke. MERV 13 captures very fine particles, including many bacteria-size ones, and is the highest rating most home systems are designed for.

No. A fiberglass filter is not bad for the system; it is easy on airflow and does its main job of keeping dust off the coil and blower. Its limit is air quality, since pollen, dander and fine dust pass through. It is a good choice for a rental, an older system, or anyone who changes filters often. A clogged filter of any kind is what hurts an AC, so a cheap filter changed monthly beats an expensive one left in for six months.

It can if the system was not designed for it or the filter is left in too long. Denser media restricts airflow more, and the restriction grows as the filter loads. In a humid climate, low airflow can freeze the evaporator coil and cut cooling. Most modern systems handle MERV 8–11 in a 1-inch slot. If you move to MERV 13 and notice louder airflow, weak vents or longer run times, go back to MERV 8 or ask your HVAC tech about a 4-inch media cabinet.

The arrow points in the direction of airflow: away from the return grille and toward the air handler or furnace. On a ceiling return that means the arrow points up into the ceiling, and on a wall return it points into the wall. At a filter slot on the air handler, it points into the unit. A backwards filter filters less and, on pleated filters, can pull away from its frame.

The depth of the media. A 4-inch deep-pleat filter goes in a media cabinet beside the air handler and holds several times more dirt than a 1-inch filter at the same MERV rating, so it lasts months instead of weeks and restricts airflow less. The two are not interchangeable: a 1-inch filter in a 4-inch cabinet leaves a large bypass gap, and a 4-inch filter will not fit a 1-inch grille. Check the brand on your cabinet door, since Honeywell/Lennox-style and standard 4-inch housings differ slightly.

No. MPR is 3M's own rating for Filtrete filters and MERV is the industry standard. As a rough guide, Filtrete 300 MPR is about MERV 5, 700 MPR is about MERV 8, 1000–1085 MPR is about MERV 11, and 1500–1900 MPR is about MERV 12–13. The Filtrete filters on this page list both ratings in their names, so you can compare them directly with True Blue, Purafilter and BestAir.

Yes. Every filter on this page can be set up on Auto Restock from its product page. Choose your size and how often you change it, and it ships on that schedule at 5% off. If you have several returns in different sizes, set up each one. You can also buy a year of filters at once and pick them up in store.

Family Hardware stocks AC and furnace filters at both stores, and every size on this page can be ordered online for free in-store pickup. Cape Coral: 622 SE 47th Terrace, (239) 542-6365. Fort Myers: 13101 McGregor Blvd, (239) 933-1744. Open Mon–Sat 7 AM–6 PM and Sun 8 AM–3 PM. Bring the old filter if you are not sure of the size.

Related Guides

These overlap with this list more than you would expect — often the same shopper, and frequently the same aisle.

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Pick It Up Today in Cape Coral or Fort Myers

Order online for free in-store pickup — usually ready within 2 hours — or just come in. Prices shown are our everyday shelf prices at both stores; stock on any single item is on its product page.

Family Hardware Cape Coral

622 SE 47th Terrace, Cape Coral, FL 33904

(239) 542-6365

Mon–Sat 7 AM–6 PM | Sun 8 AM–3 PM

Departments, services and directions for our Cape Coral store →

Family Hardware Fort Myers

13101 McGregor Blvd, Fort Myers, FL 33919

(239) 933-1744

Mon–Sat 7 AM–6 PM | Sun 8 AM–3 PM

Departments, services and directions for our Fort Myers store →

Free shipping on orders over $99 • Free in-store pickup • Online customer service: 877-755-2005

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