Don't Waste Your Money is supported by our readers. When you purchase an item through links on our site, we may earn an affiliate commission.

The Best 20x25x4-Inch Furnace Filter - 2021

Last updated on September 14, 2021
Best 20x25x4-Inch Furnace Filter

Why Trust The DWYM Score?

DWYM is focused on helping you make the best purchasing decision. Our team of experts spends hundreds of hours analyzing, testing, and researching products so you don't have to.Learn more.

Look for the DWYM seal for products that are the best in a category.

Our Picks For The Top 20x25x4-Inch Furnace Filters

Show Contents
Our Take
  Our Top Pick

Filtrete MERV 12 NDP03-4IN-2P-2 20x25x4-Inch Furnace Filter, 2-Pack

Don't Waste Your Money Seal of Approval

Filtrete

MERV 12 NDP03-4IN-2P-2 20x25x4-Inch Furnace Filter, 2-Pack

Overall Take

Traps Unwanted ParticlesThis furnace filter minimizes unwanted air particles while letting clean air flow through.

  Runner Up

Filtrete MERV 11 NADP03-2PK-2 20x25x4-Inch, 2-Pack

Filtrete

MERV 11 NADP03-2PK-2 20x25x4-Inch, 2-Pack

Overall Take

Outperforms FiberglassThis furnace filter is highly effective at capturing microparticles.

  We Also Like

FilterBuy 20x25x4-Inch MERV 8 Furnace Filter, 2-Pack

FilterBuy

20x25x4-Inch MERV 8 Furnace Filter, 2-Pack

Overall Take

Traps 90% of Particles This air filter for your furnace protects your home from dust, pollen and more.

  Strong Contender

Nordic Pure MERV 12 20x25x4-Inch Furnace Filter, 2-Pack

Nordic Pure

MERV 12 20x25x4-Inch Furnace Filter, 2-Pack

Overall Take

Hypoallergenic and PleatedThis pleated furnace filter is ideal for those who suffer from allergies.

Avatar
Guide written by Anam Ahmed
Last updated on September 14, 2021

Indoor air quality is a hot topic of conversation, and it’s important to do what you can to ensure the air you and your family are breathing is safe and clean. A high-quality HVAC or furnace filter is a good way to ensure you’re removing harmful pollutants and germs out of the air. Furnace filters are designed to remove dust, dirt and debris from the air stream, which also helps to extend the longevity of your furnace’s motor.

There are many varieties of furnace filters, each with advantages and drawbacks. Electrostatic filters are long-lasting and washable. They have an electronic charge and work like a magnet to attract dust particles.  Pleated filters increase the furnace area and can capture more particles in the air. They are deeper than other kinds of filters, so it’s best to see whether your furnace can accommodate them.

HEPA filters are popular for air purifiers and vacuums, but they are not as effective for furnaces because they can create a high amount of air flow resistance. They can often reduce air flow in the house, which affects the heating and cooling process. Activated carbon furnace filters absorb chemicals, fumes and odors from the air. They also remove allergens, harmful chemicals and other air pollutants.

The Best 20x25x4-Inch Furnace Filters

1
  Our Top Pick

Filtrete MERV 12 NDP03-4IN-2P-2 20x25x4-Inch Furnace Filter, 2-Pack

This furnace filter uses three-in-one technology to trap unwanted particles. It can capture smoke, cough and sneeze debris, bacteria, viruses and more. The filter has a rating of MERV 12.

Features


Specifications

Brand
Filtrete
Model
2
  Runner Up

Filtrete MERV 11 NADP03-2PK-2 20x25x4-Inch, 2-Pack

This washable and non-electrostatic furnace filter traps pollen, pet dander, smoke, bacteria and viruses. It has a MERV rating of 11 and a 1000 Microparticle Performance Rating. The filter should be changed every 90 days.

Features


Specifications

Brand
Filtrete
Model
3
  We Also Like

FilterBuy 20x25x4-Inch MERV 8 Furnace Filter, 2-Pack

Trap 90% of air particles from dust, pollen and other pollutants. This pleated furnace filter is industrial-grade with dual wire backings. It outperforms standard cardboard designs.

Features


Specifications

Brand
FilterBuy
Model
4
  Strong Contender

Nordic Pure MERV 12 20x25x4-Inch Furnace Filter, 2-Pack

If you suffer from allergies, this hypoallergenic and pleated furnace filter is a good option. It keeps out allergens, dust, pollen and other airborne contaminants. It should be changed every three to six months.

Features


Specifications

Brand
Nordic Pure
Model
5
  Also Great

Aerostar MERV 8 20x25x4-Inch Furnace Filter, 6-pack

This furnace filter is easy to install. This six-pack of filters makes it easy to change your furnace filter often. The filter is 100% synthetic electrostatic media for high efficiency.

Features


Specifications

Brand
Aerostar
Model

Our 20x25x4-Inch Furnace Filter Buying Guide

Indoor air quality is a hot topic of conversation, and it’s important to do what you can to ensure the air you and your family are breathing is safe and clean. A high-quality HVAC or furnace filter is a good way to ensure you’re removing harmful pollutants and germs out of the air. Furnace filters are designed to remove dust, dirt and debris from the air stream, which also helps to extend the longevity of your furnace’s motor.

There are many varieties of furnace filters, each with advantages and drawbacks. Electrostatic filters are long-lasting and washable. They have an electronic charge and work like a magnet to attract dust particles.  Pleated filters increase the furnace area and can capture more particles in the air. They are deeper than other kinds of filters, so it’s best to see whether your furnace can accommodate them.

HEPA filters are popular for air purifiers and vacuums, but they are not as effective for furnaces because they can create a high amount of air flow resistance. They can often reduce air flow in the house, which affects the heating and cooling process. Activated carbon furnace filters absorb chemicals, fumes and odors from the air. They also remove allergens, harmful chemicals and other air pollutants.

DWYM Fun Fact

The MERV, which stands for Minimum Efficiency Reporting Value, is the standard that is used to indicate a furnace filter’s efficiency. The MERV scale identifies the size of particles that the filter can eliminate from the air. For example, a filter with MERV 6 can filter out dust, lint and pollen while a filter with MERV 6-11 can filter out other things like smog and large respiratory droplets. If you want to filter out viruses and bacteria, you will need a filter rated MERV 6-13. For specialized setting such as hospitals and clean rooms, you need to use filters with MERV 16 or higher.

The 20x25x4-Inch Furnace Filter Tips and Advice

  • Furnace filters come in different sizes, such as 20 by 25 by 4 inches. Be sure to check the size that is required by the make and model of your furnace. You will not be able to substitute different sizes of filters, so it’s vital to get the exact size that is required for your furnace.
  • Changing or washing your furnace filters on a regular basis is key. Otherwise, you furnace filter cannot do its intended job. Each type of filter typically has a recommendation for when it should be changed or cleaned. As a rule of thumb, plan to replace or wash your furnace filter once every three months.
  • In some cases, such as in really hot climates where the HVAC system runs constantly in the summer, you may need to replace or wash your furnace filter more frequently. This also applies to homes which have pets, as their dander and fur can cause furnace filters to need faster replacement.

About The Author

Avatar
Anam Ahmed 

Anam Ahmed is a copywriter and essayist based in Toronto. She has been writing on technology, travel, parenting, and business for over 10 years, and works with a number of high-profile organizations. She values finding the best products to make people's lives easier. Anam earned an M.A. from the University of Toronto and a B.A.H. from Queen's University. Learn more at www.anamahmed.ca.