Filterbuy Pet Allergy Defense MERV 11 4-inch Furnace Filter: MERV 11

Why it matters

The Filterbuy Pet Allergy Defense MERV 11 4-inch Furnace Filter is a pleated furnace and air conditioner filter rated MERV 11.

MERV 11 is the usual allergy upgrade: it catches most pollen, pet dander and mold spores, and part of the 1 to 3 micron range.

Deep pleated filters hold several times the media of a 1-inch filter, so they run with less resistance and last longer.

As general guidance, check a 1-inch filter monthly and change it every one to three months; deeper 4- and 5-inch filters usually last six to twelve months.

This listing is the 16x25x4 size; order by the size printed on your old filter's frame.

The Filterbuy listing names 4 filters per box.

Compared with the Filterbuy Dust & Allergy Defense MERV 8 Air Filter: MERV rating 11 here vs 8.

Who it's for, and who should skip it

Good fit if

Allergy households
Homes that change filters on schedule

Look elsewhere if

Smoke or fine-particle control

Pros and cons

Pros

MERV 11

Cons

Measure your slot: nominal and actual sizes differ

Limitations to weigh

Specifications are the maker's or seller's own figures; check fit against your equipment's model number and the actual size.

Specifications

The bracket shows where each figure comes from.

Model number	AFB16x25x4M11pk4	Retailer
MERV rating	11	Retailer
Dimensions (seller)	24.5"L x 15.5"W x 3.63"Th	Retailer
Compatible devices	Air Cleaner, Air Conditioner, Furnace, HVAC System, Heat Pump	Retailer

Alternatives worth comparing

Simply MERV 11 4-inch Furnace FilterMERV 11 from Simply.

Aerostar 20x20x2 Pleated MERV 11 Air FilterMERV 11 from Aerostar.

AIRx MERV 11 4-inch Furnace FilterMERV 11 from AIRx.

More hvac and furnace filters we cover

All hvac and furnace filters, compared in one table · Every Filterbuy product we cover

Final verdict

A well-matched choice for allergy households. Confirm the model it fits before ordering.

Where to buy

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Questions buyers ask

Is MERV 11 right for my home?

MERV 11 is the usual allergy upgrade: it catches most pollen, pet dander and mold spores, and part of the 1 to 3 micron range. If your system is old or the filter slot is a 1-inch return grille, watch for whistling or a filter that bows; those are signs to step down a grade.