What MERV Rating Do I Need? MERV 8 vs 11 vs 13 (2026)

For most homes, buy a MERV 11 filter in the size printed on your old one, and change it every 60 to 90 days. Pick MERV 13 for allergies, pets or smoke: the EPA says most home systems can take it if you change it on time. Pick MERV 8 only for an older system or a weak blower.

Your filter size

It's printed on the edge of your old filter.

MERV 8

Dust, lint and pollen. Easiest on airflow, for an older system.

Aerostar 16x25x1, 6-pack

$5.99 per filter

$35.95 for 6 · $24 to $36 a year

Buying more? Filtrete 12-pack, $67.63 ($5.64 each), from a third-party seller.

Check price on Amazon

MERV 11 · most homes

Adds fine dust, mold spores and pet dander. Right for most homes.

Amazon Basics 16x25x1, 6-pack

$5.73 per filter

$34.38 for 6 · $23 to $34 a year

Buying more? AIRx 12-pack, $63.99 ($5.33 each), from a third-party seller.

See Aerostar on Amazon

MERV 13

Adds smoke, bacteria and most fine particles. For allergies, pets or smoke.

Filter King 16x25x1, 6-pack

$7.99 per filter

$47.94 for 6 · $32 to $48 a year

See BNX on Amazon

The lowest price per filter we found on Amazon at each MERV, packs of 6 or fewer, buy boxes read November 11, 2026. A year = 4 to 6 changes of a 1-inch filter.

MERV 8 vs MERV 11

Pick MERV 11 unless your system is old or struggles for airflow. MERV 8 catches dust, lint and pollen. MERV 11 also catches finer dust, mold spores and pet dander, and most home systems handle it fine.

Right now the step up costs nothing: in 16x25x1, our MERV 11 pick is $5.73 per filter and our MERV 8 pick is $5.99. Prices read on Amazon November 11, 2026.

MERV 11 vs MERV 13

Pick MERV 13 if anyone has allergies or asthma, you have pets, or you get wildfire smoke. It adds smoke, bacteria and most fine particles (PM2.5). It is a little harder on airflow, so change it on time. A 1-inch slot usually takes it; a 4-inch filter is easier on the blower.

It costs about $2.26 more per filter than MERV 11 ($5.73 vs $7.99), or $9.04 to $13.56 a year.

Not sure? MERV 11 is the safe middle for most homes.

Your size not listed? The picker at the top covers the 15 sizes we price. For every listing we found in each size, see all furnace filters by size. Have an Aprilaire, Honeywell or Lennox filter cabinet? See which 4-inch filter fits it.

Buying for one of the most common sizes? See the picks and prices for 16x25x1, 20x25x1, 20x20x1, 16x20x1, 20x25x4 and 16x25x4.

MERV, MPR and FPR — the same thing, three scales

Stores relabel MERV to their own numbers. MPR is 3M/Filtrete’s scale; FPR is Home Depot’s. This is the conversion:

Tier	MERV	MPR (3M)	FPR (Home Depot)	What it captures
Good	8	600	5	Pollen, dust, lint; traps at least 70% of 3-10 micron particles (EPA)
Better	11	1000-1200	7	Adds fine dust, mold spores, pet dander; at least 65% of 1-3 micron particles (EPA)
Best-	12	1500	8-9	At least 35% of the smallest (0.3-1 micron) particles (EPA)
Best	13	1900	10	Adds smoke and bacteria; at least 50% of 0.3-1 micron particles (EPA)

MPR = 3M/Filtrete proprietary; FPR = Home Depot proprietary (private-label + Honeywell-branded at HD). Neither appears in any central directory. MERV (ASHRAE 52.2) is the only cross-brand standard.

The catch: MERV vs. airflow

A higher MERV usually means denser filter media, so your blower works harder to pull air through it. Brands differ a lot: in the numbers makers file with California, Filtrete's MERV 13 is as easy on airflow as a MERV 8 from another brand (see the airflow data). For the numbers by brand and size, see is MERV 13 too restrictive? Push too far on a thin 1-inch filter and you can lose airflow, raise your energy bill, and even ice up the coil. Two safe rules:

1-inch slot: MERV 11–13 is the ceiling for most systems. Change it on time — a clogged MERV 8 restricts airflow more than a fresh MERV 13.
Want MERV 13+ with less drag? Use a 4-inch filter if your system has a deep slot — more surface area means the same filtering with far less restriction, and it lasts 6–12 months.

Find your size

Read the size printed on your current filter — that’s the nominal size. Actual dimensions run about half an inch smaller. Common sizes:

Nominal size	Actual size	Depth
14x25x1	13.5 x 24.5 x 0.75	1"
16x20x1	15.5 x 19.5 x 0.75	1"
16x25x1	15.5 x 24.5 x 0.75	1"
20x20x1	19.5 x 19.5 x 0.75	1"
20x25x1	19.5 x 24.5 x 0.75	1"
16x25x4	15.375 x 24.375 x 3.625	4"
20x25x4	19.375 x 24.375 x 3.625	4"

See furnace filters ranked by MERV & yearly cost →

Common questions

What MERV rating is best for a home?

For most homes, MERV 11 to 13 is the sweet spot — it captures fine dust, pollen, mold spores and a good share of smoke and bacteria, without choking airflow on a standard system. Go to MERV 8 if anyone in the home is sensitive to airflow loss or the system is older; go to MERV 13 for allergies, pets or wildfire smoke.

Is a higher MERV always better?

No. A higher MERV traps smaller particles but also restricts airflow more. On a 1-inch filter slot, pushing past MERV 13 can starve the blower, raise energy use and even freeze the coil. Match the MERV to what your system can move — when in doubt, MERV 11–13 in a 1-inch slot, or a thicker 4-inch filter if you want MERV 13+ with less restriction.

What is the difference between MERV, MPR and FPR?

They measure the same thing — how well a filter traps particles — but MERV is the industry ASHRAE standard, MPR is 3M/Filtrete’s own scale, and FPR is Home Depot’s. Use the cross-map on this page to convert: e.g. MERV 13 ≈ MPR 1900 ≈ FPR 10.

How often should I change my furnace filter?

A 1-inch pleated filter every 60–90 days; sooner with pets, smoke or allergies, because they clog faster. A 4-inch filter can last 6–12 months. A clogged filter restricts airflow just like too high a MERV — so changing on time matters as much as the rating you pick.

What size filter do I need?

Read the size printed on your old filter (e.g. 20x25x1) — that is the nominal size. The actual size is about half an inch smaller. Match the nominal size when you buy; the size chart on this page lists the common ones and their true dimensions.

Filter ratings and the MERV/MPR/FPR cross-map are compiled from published manufacturer and retailer specifications. There is no federal filter directory; California keeps a state list of tested filters, which we use in Filtrete vs Nordic Pure vs Aerostar. Written by Erin Rose. See our methodology.

What MERV rating do I need?