Trusted in filtration since 2006

Furnace Filters

Replacement furnace filters for every home and light-commercial system — every size, every MERV, cut to 1/8″ when a standard size won't fit. Shipped fast from a filtration specialist trusted since 2006.

Every sizeStandard or cut to 1/8″
MERV 1–13Basic to hospital-grade
Since 2006HVAC filtration specialists
$50+Free U.S. shipping
Shop by size Need a custom size?
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Shop by size

Find your furnace filter size

The size is printed on the frame of your current filter (e.g. 16x25x1). Pick yours below, or measure in 60 seconds. Don't see your size? Every dimension is available cut to 1/8″.

16x25x120x25x116x20x120x20x114x25x114x20x124x24x112x12x118x24x116x24x120x30x112x24x114x24x118x18x120x24x125x25x116x25x420x25x416x20x420x20x424x24x216x25x220x25x214x25x4Custom size →
Homeowners

Residential furnace filters

The same filters the pros use, shipped to your door. 1″ and 2″ pleated for furnaces, heat pumps, and central AC — MERV 8 for everyday, MERV 11–13 for allergies, pets, and wildfire smoke.

Shop residential → Facilities & contractors

Commercial furnace filters

Pleated, box, and bag filters for RTUs, air handlers, schools, clinics, and multi-site portfolios. PO terms, tax-exempt purchasing, W-9/COI, and recurring delivery for qualified accounts.

Shop commercial →
Buying guide

Choosing the right furnace filter

A quick, expert reference on MERV, depth, and sizing — so you order the right filter the first time.

MERV ratings in plain language

MERV (Minimum Efficiency Reporting Value) measures how well a filter captures particles. Higher MERV captures smaller particles but adds airflow resistance — match it to your system and your air-quality needs, not just the highest number.

MERV 1–4
Equipment protection. Fiberglass panels — max airflow, catches large dust and lint. The budget/high-flow choice.
 MERV 8
Everyday pleated. Captures pollen, dust mites, and lint. The common residential and light-commercial default.
 MERV 11
Allergy & pets. Finer dust, pet dander, mold spores. A good upgrade for allergy-sensitive homes.
 MERV 13
Smoke & aerosols. Bacteria-sized particles and wildfire smoke. Standard for healthcare and post-2020 school specs.

1″, 2″, or 4″ depth?

The third number in your size (e.g. 16x25x1) is the depth. Deeper filters hold more dust and last longer at lower airflow resistance — if your system fits them.

1″
Standard residentialMost furnaces, heat pumps, and central AC use 1″. Change every 30–90 days.
2″
Upgraded residentialMore media, lower resistance at the same MERV, longer service life.
4″
High-efficiency & commercialMedia cabinets and commercial RTUs. Longest intervals, lowest fan energy.

Not a standard size? Build any dimension in 1/8″ increments with the custom filter builder.

Common questions

Furnace Filters: frequently asked

Is a furnace filter the same as an AC filter?

Yes — in a central forced-air system, the furnace and the air conditioner share the same air handler and the same filter. A "furnace filter," "AC filter," "air conditioner filter," and "HVAC filter" are all the same product. Match the size and MERV to your system and you're set.

How often should I change my furnace filter?

A 1″ pleated filter typically lasts 30–90 days; homes with pets, allergies, or heavy use are on the shorter end. 2″ and 4″ filters last longer. If it looks gray and loaded, change it — a clogged filter strains the blower and drives up energy costs. More on that here.

What size filter do I need?

The nominal size is printed on the cardboard frame of your current filter (e.g. 16x25x1 = 16″ × 25″ × 1″ deep). Order that size. The actual cut size is usually about ½″ smaller on width and height — that's normal. Not sure? Our 60-second measuring guide walks through it, and any size is available cut to 1/8″.

What MERV rating should I use?

MERV 8 is the everyday default. Go MERV 11 for allergies or pets, MERV 13 for wildfire smoke or anyone with respiratory sensitivity. Higher isn't always better — very high MERV can restrict airflow on older systems, so if in doubt, MERV 8–11 is the safe range for most residential equipment.

Which way does the arrow on the filter point?

The airflow arrow printed on the filter frame points toward the blower / furnace — i.e. in the direction the air is moving, away from the return duct. Installed backwards, the filter is less effective and can restrict airflow.

Do you carry my exact size if it's not standard?

Yes. Any width and height, in 1″–6″ depths and MERV 1–13, is available built to your exact dimensions in 1/8″ increments through the custom filter builder — no more cutting standard filters down.

Can I set up recurring filter delivery?

Yes — subscribe to any filter at checkout for automatic delivery at 30, 60, 90, 180, or 365-day intervals and save 10%. For facility-scale recurring orders across multiple sites, our commercial team can set up standing orders and PO terms.

Do you supply businesses, schools, and government buyers?

Yes. We support PO ordering, net terms, tax-exempt purchasing, and W-9/COI documentation for qualified commercial, education, healthcare, and government accounts. Start with our commercial services page or request a quote.

Still not sure which filter you need?

Tell us your size and system — our filtration specialists (50+ years combined HVAC experience) will point you to the right filter.

How to measure Build a custom size Call 866-469-8556