Home Air Filters & Indoor Air Quality

Stop guessing your filter size. Get it exact.

Three quick questions about your HVAC system and household — one precise recommendation for dust, allergies, or pet odor, sized to fit and ready to order.

Start the 30-Second Quiz NO SIGNUP REQUIRED · TAKES ~30 SEC
Sizes covered
Standard + Custom
Rating range
MERV 8–13
Result
Exact match
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The Match Tool

Answer three questions.
Get your exact filter.

We'll ask for your size and household conditions — pets, allergies, or everyday dust — and turn it into a specific recommendation for cleaner indoor air, plus a direct link to buy it in the right size.

What's your filter size?
Check the cardboard edge of your current filter — the size is printed there.
Tell us about your household
Select everything that applies.
Your recommended filter
Recommended Rating
MERV 11

Captures pet dander, mold spores, and most allergens without restricting airflow.

SIZE: 20x20x1  |  MERV: 11  |  TYPE: Pleated

Opens Amazon search results filtered to your exact size and MERV rating.

Redirecting you to the exact size and rating you need...

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Common air filter sizes, explained

Every HVAC system uses a specific filter size — printed on the cardboard edge of your old filter. Here's what the most-searched sizes are typically used for, so you can double-check before you order.

16x25x1 Air Filter

One of the most common sizes in single-family homes with standard 1-inch furnace slots.

20x25x1 Air Filter

Common in larger homes and central air systems with higher airflow needs.

20x20x1 Air Filter

Frequently used in apartments, condos, and homes with wall or ceiling return vents.

20x20x4 Air Filter

A thicker, higher-capacity filter used in systems with a dedicated filter cabinet.

How to read a MERV rating

MERV (Minimum Efficiency Reporting Value) measures how well a home air filter traps particles, on a scale of 1–20. Higher isn't always better — a rating too high for your HVAC system can restrict airflow and strain the blower motor.

For most homes, MERV 8–11 balances clean indoor air with airflow, handling everyday dust, pollen, and pet odor. MERV 13 approaches HEPA-level filtration and is best reserved for allergy, asthma, or smoke-sensitive households — and only if your system is rated to handle it.

RatingBest forChange every
MERV 8Standard homes, dust & pollen90 days
MERV 11Pets, mild allergies60–90 days
MERV 13Allergies, asthma, smoke60 days

Common questions

How often should I really change my filter?

Every 60–90 days for most 1-inch filters, more often with pets or during high-pollen seasons. A dirty filter restricts airflow and makes your system work harder.

What if my filter size isn't standard?

Enter your exact dimensions in the custom size field — custom sizes are common in older homes, and dedicated filter retailers can cut to size where standard retailers can't.

How do I install my air filter?

Turn off your HVAC system, remove the old filter, insert the new one with the arrow pointing toward the system, then turn it back on.

Does a higher MERV rating always mean cleaner air?

Not on its own. A rating higher than your HVAC system is designed for can restrict airflow and reduce efficiency. Match the rating to your system, not just the highest number available.

What size air filter do I need for my house?

Check the cardboard edge of your current filter — the size is printed there as three numbers, like 20x25x1. If you can't find your old filter, measure the width, height, and depth of the slot where it sits (round up to the nearest inch).

Can I use a thicker filter than my system calls for?

No — filter thickness (the third number, like the "1" in 20x25x1) is sized to the exact depth of your filter slot. A thicker filter usually won't fit, and forcing one in can damage the door or seal.

How do I know if I need a MERV 8, 11, or 13 filter?

MERV 8 covers general household dust for most homes. MERV 11 adds pet dander and mold spore capture. MERV 13 is for allergy, asthma, or smoke-sensitive households — but confirm your HVAC system supports it first, since higher ratings restrict airflow more.

Do air filters help with pet odor and dust?

Yes — a MERV 11 filter is the typical sweet spot for pet households, trapping dander and airborne odor particles without over-restricting airflow. For heavy dust or multiple pets, MERV 13 offers stronger capture if your HVAC system supports it.

Is a MERV 13 filter the same as HEPA?

Not quite. True HEPA filters capture 99.97% of particles but are too dense for most home HVAC systems. MERV 13 is the closest home-compatible option, offering HEPA-level filtration for allergens and smoke without the airflow restriction of true HEPA.

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