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20x25x4 MERV 11 Air Filters

Name: 20x25x4 MERV 11 Air Filter
Brand: Filter King
SKU: FK20x25x4-M13
Price: 45.55 USD
Availability: InStock
Rating: 4.6666665 (252 reviews)

Actual size: 19.5 x 24.5 x 3.75 inches

Choose filter quality

Filter guide

MERV 8 MERV 11 MERV 13 ODOR ELIMINATOR

Advanced

Deep pleated air filters for whole-house and commercial HVAC systems

Learn more

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20x25x4 air filter description

SKU

FA20X25X4
MERV rating

MERV 11
MPR rating

MPR 1000-1200
FPR rating

FPR 7
Filtration efficiency

95%
Odor eliminator

No
Captured particle size

1-10 microns
Lifespan

6-12 months

What does MERV 11 protect against?

MERV 11 filters remove up to 95% of common particles including fine dust, smoke, and smog particles. These filters reduce allergy symptoms and protect against outdoor air pollution.

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Fast & free shipping

Processed quickly, ships fast, free for all orders
Easy to return/exchange

Return your items within 30 days and get a full refund
All sizes available

Find your perfect fit with our complete size range

Who is the 20x25x4 MERV 11 best for?

MERV 11 air filters are designed for homes with allergies and in some cases, asthma. Those with respiratory illnesses or compromised immune systems may benefit from MERV 11 air filters due to these filters being significantly more powerful than alternative MERV filters at capturing smaller particles, such as MERV 8.

When to replace your 4-inch air filter?

Thicker filters last longer, but a 4-inch filter still needs fresh media over time. Here's a simple guide based on your household.

Asthma or allergies

Every ~4 months

Thicker media traps more, but allergy sufferers still benefit from a fresh 4-inch filter roughly every 4 months.
Pets

Every ~6 months

A 4-inch filter has more room for pet hair and dander, so plan on a change about every 6 months in most homes.
Young children

Every 6–9 months

For homes with young kids, a 4-inch filter typically lasts 6 to 9 months before it needs replacing.

What happens if you don’t replace on time?

Your filter catches dust every day, but it can only hold so much. Once it's full, dirty air keeps circulating and your system has to work harder – leading to problems that spread through your whole home.

Higher energy bills

A clogged filter makes your system work much harder to push air through. That extra effort shows up on your energy bill.
Costly system breakdowns

When air can't flow through, your AC can freeze up in summer and your furnace can overheat in winter.
Stuffy, uncomfortable rooms

A dirty filter weakens your system's airflow, so some rooms end up too hot, too cold, or just plain stuffy.

MERV rating comparison

Recommended for

Comparable ratings

Filtration efficiency

Dust mites

10+ microns

Pollen

10-100 microns

Pet dander

5-10 microns

Lint and fabric fibers

10+ microns

Mold spores

3-10 microns

Fine dust

1-3 microns

Smoke particles

0.3-1 micron

Smog and fine particles

0.1-1 micron

Bacteria

0.3-5 microns

Virus carriers

0.3-1 micron

Wildfire smoke

0.4–2.5 microns

Odors and gases

Molecular level

VOCs

Molecular level

Cooking odors

Molecular level

Learn more

Basic air quality,
standard homes

FPR 5,
MPR 600

90% of common particles

MERV 8 filters

Better air quality, homes with allergies, pets

FPR 7,
MPR 1000-1200

95% of common particles

MERV 11 filters

Superior air quality, health concerns, allergies

FPR 10,
MPR 1500-1900

98% of common particles

MERV 13 filters

Odor control, cooking smells, pet areas

FPR 5 + Carbon,
MPR 600 + Odor

90% of common particles

Odor eliminator filters

What makes Filter King so good?

It comes down to using better materials. Click around to see how we build a stronger filter that actually protects your home.

Front beverage board frame

The diagonal straps die-cut into the frame bond to each pleat tip, keeping them evenly spaced so the filter won't bow.

MERV 11 pleated media

Rated to capture up to 95% of common particles, MERV 11 media catches dust mites, pollen, pet dander, and mold spores, as well as fine dust and smoke.

Wire support grid

An expanded wire grid bonds to the media, stopping the pleats from shifting or pulling away under airflow.

Back beverage board frame

The same heavy-duty, moisture-resistant beverage board on the exit side holds its shape and keeps a tight seal in your vent or wall slot.

Activated carbon layer

A layer of activated carbon absorbs odor molecules from cooking, pets, and chemical fumes – catching what the filter media alone can't.

Customer reviews

How to find your air filter size?

Check the label on your current filter or use a tape measure to get the exact length, width, and depth before selecting your size.

Nominal size

Nominal size is what you normally see printed on the label. This is usually a rounded size which is often not the true size of your filter.

Actual size

Actual size is the true size of the air filter, usually written in smaller font below the nominal size.

Measuring

Measure your current air filter or the length, width, and depth of the opening slot to get the actual size. Round it up to the nearest whole inch to get the nominal size.

How to install 20x25x4 air filter?

Installing 20x25x4 air filters couldn't be easier. Just make sure to align the arrow printed on the side with the airflow direction!

1

Remove the air filter from the package
2

Locate the arrow and point it in the direction of the fan
3

Slide the filter in to the slot of the central unit
4

For return grills, insert the filter into the grill, pointing the arrow inwards

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Pay full price on every order
Need to remember to reorder every time you run out
Forget to reorder, and a dirty filter can drive up your energy bills.

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Frequently asked questions

Frequently Asked Questions (FAQs)

Will a 20x25x4 MERV 13 filter restrict airflow in my system?

No, 20x25x4 MERV 13 filters are designed with deeper pleats for proper airflow. A 4-inch depth captures particles with an expanded surface area without sacrificing airflow.

Do I need special housing for 20x25x4 air filters?

Yes, your HVAC unit must accommodate 20x25x4 air filters with a proper return air rack and media cabinet. Always verify filter slot size and depth before purchasing a 20x25x4 replacement air filter.

How do I know when my 20x25x4 filter needs replacement?

If you notice reduced airflow, increased dust collection, and higher energy bills, it may be time for a 20x25x4 filter replacement. Most 20x25x4 air filters last between 6 and 12 months.

Are 20x25x4 filters harder to install than thinner filters?

No, the installation of 20x25x4 filters is straightforward and typically installed in the same way as 1-inch air filters. Always check that airflow arrows (printed on the filter's frame) are facing towards the blower. Proper handling (without forcing or bending the filter) prevents damage and inefficiency.

Can I fold or bend a 20x25x4 filter to make it fit?

No, folding or bending a 20x25x4 air filter can damage the pleats and frame. This can result in reduced efficiency and airflow. Using the correct size for your HVAC system is essential.

Can I vacuum my 20x25x4 filter to extend its life?

No, it is not recommended to vacuum your 20x25x4 filter when it is clogged with particles and dust. However, a light vacuuming may temporarily allow your filter to last as you await a new 20x25x4 air filter replacement.

Will a 20x25x4 filter improve my energy bills?

Yes, a new 20x25x4 filter will reduce your HVAC unit's strain while simultaneously improving airflow and efficiency. The more efficient your HVAC system's air filter, the more efficient your unit will be.

20x25x4 MERV 11 Air Filters

Choose filter quality

Advanced

Select quantity

20x25x4 air filter description

What does MERV 11 protect against?

Choose how to buy

Who is the 20x25x4 MERV 11 best for?

When to replace your 4-inch air filter?

Asthma or allergies

Pets

Young children

What happens if you don’t replace on time?

Higher energy bills

Costly system breakdowns

Stuffy, uncomfortable rooms

MERV rating comparison

What makes Filter King so good?

Front beverage board frame

MERV 8 pleated media

MERV 11 pleated media

MERV 13 pleated media

MERV 8 pleated media

Wire support grid

Back beverage board frame

Activated carbon layer

Customer reviews

How to find your air filter size?

Nominal size

Actual size

Measuring

How to install 20x25x4 air filter?

Set it and forget it with auto-delivery

Without auto-delivery

With auto-delivery (save 5%)

Frequently Asked Questions (FAQs)

Will a 20x25x4 MERV 13 filter restrict airflow in my system?

Do I need special housing for 20x25x4 air filters?

How do I know when my 20x25x4 filter needs replacement?

Are 20x25x4 filters harder to install than thinner filters?

Can I fold or bend a 20x25x4 filter to make it fit?

Can I vacuum my 20x25x4 filter to extend its life?

Will a 20x25x4 filter improve my energy bills?