The Best Furnace Filter 20-x-25-x-4

Your guide to this review today is by Cleaning expert Adam Barker
Published on
February 27th, 2019

Expert BioExpert Bio

Adam has a passion for cleaning from his youth growing up in England, and he has carried it with him to the US. Adam’s formal training and certifications in cleaning include the Advanced System Cleaning specialist (For HVAC cleaning / ductwork), through NADCA (this is the highest certification that NADCA has), as well as several other certifications from the IICRC. Adam has either advised, consulted, or done research with dozens of cleaning and cleaning related business entities. Adam holds an undergraduate degree from Oxford, a Master’s degree from Oxford, and a Master’s degree from Harvard Business School.

The Cleaning Institute

Furnace filters are designed to trap harmful pollutants and particles in the air to prevent them from circulating in different rooms of buildings to create a clean and habitable setting in the home or apartment space. Without a filter, furnaces can’t operate well and can contribute to poor air quality in residential and commercial buildings. We tested furnace filters with a size of 20-x-25-x-4 to narrow down the best options for consumers to purchase for their home or office. Our top pick is the Aerostar 20x25x4 MERV 11 Pleated Air Filter because it has a high capacity and is similar to 3M Filtrate Mpr 1000 to 1200 Micro Allergen Defense, along with Honeywell Allergen Plus FPR 7. It’s useful for trapping dust mites, lint, smoke, pet dander, dust, and mold spores that circulate in the air to maintain a cleaner setting, where residents can breathe easily and improve their health. The Filtrete 20x25x4, AC Furnace Air Filter, MPR 1550 DP, Healthy Living Ultra Allergen Deep Pleat is our honorable mention because it is able to outperform fiberglass and is washable with its non-electrostatic 3-month pleated 1-inch home air filters. The product is designed to be used in residential properties and can trap microscopic particles.

Testing Categories

For our years, we’ve used multiple testing categories during our process to rate each product that we review and determine where it stacks up compared to similar products on the market. For our furnace filter tests, we used categories that included efficiency, durability, and application.

Efficiency: The efficiency of each furnace filter is a top category because it determines if the item is worth purchasing and investing in for the home or office. We evaluated how many particles and pollutants the filters collected. We also researched the claims made by each manufacturer to determine what they claimed each filter would trap and whether it was true or not.

Durability: The durability of each product was influenced by the quality of its construction and the materials that were used. We took a close look at each filter’s structure and design to determine if it could hold up and continue to be effective for several months. Our tests also included determining its lifespan and how often it would need to be replaced.

Application: Installing the filter in the furnace is one of the most important parts of the quality of the product that is used because it determines how easy it is to replace. We made the application of the product one of the main categories to evaluate during our tests, which included how easily they fit into the furnace and if gaps were present around the frame.

Top Pick

Aerostar 20x25x4
MERV 11 Pleated
Air Filter

The Aerostar MERV 11 Pleated Air Filter includes six different filters, which can last up to two years, depending on the environment & the type of furnace that it’s installed in throughout the year.

Price Check

Most notable upside: The Aerostar filter is designed to have a high capacity and can be compared to the 3M Filtrate MPR 1000 to 1200 Micro Allergen Defense and the Honeywell Allergen Plus FPR 7. It’s effective in combating lint, pet dander, smoke, dust mites, mold spores, and dust, which makes it more advanced and useful when compared to similar products in the industry. Quality filtration is delivered with the product with quality materials used. Each item is constructed in state-of-the-art facilities throughout the U.S. to serve different types of customers. The filters can be used for both air conditioners and furnaces in each season. 90 percent of large airborne allergens are trapped once the product is installed, which limits excess strain on the motor and allows the appliance to work more effectively, which can increase the lifespan of the parts. The filters can also reduce the energy usage in the building for added savings each month. Less maintenance is also needed on the furnace with the use of the filters because the parts run more efficiently without encountering as many problems. By removing the main allergens, it can alleviate respiratory issues, asthma, and allergies. The product contains fiberglass and a polytheistic blend. They offer a higher level of construction and overall quality because they’re built with more pleats and are heavier. They feel more substantial and sturdy when compared to similar filters.

Biggest downsides: The filters may be too small for some units and will need to be taped in to remain secure in the furnace. The MERV rating is not clearly listed on the packaging. Some of the filters may arrive damaged. They are also not the same size as the OEM filters that they may be replacing in some buildings. Return grills may also begin to whistle once the filters are installed due to their small sizing. The air can also seep in around the edges. They are also not individually wrapped, which can cause the filters to become exposed to dirt and dust as they’re stored.

Honorable Mention

The Filtrete 20x25x4,
AC Furnace Air Filter, MPR 1550 DP,
Healthy Living Ultra Allergen Deep Pleat

The Filtrete AC Furnace Air Filter Healthy Living Ultra Allergen Deep Pleat proves it can outperform fiberglass. It improves airflow and traps pollutants with its Filtrete Brand 3-in-1 technology.

Price Check

Most notable upside: The Filtrete air filters allow clean air to flow through by trapping unwanted air particles that circulate to improve the air quality in the building. The filters are designed to attract and trap microscopic particles that include germs from coughing, smoke, bacteria, viruses, fireplace smoke, candle smoke, and sneeze debris. Large particles are also trapped, along with ultrafine particles. The product is even available in 4-inch, 4-inch slim fit, and 5-inch air filter varieties. The manufacturer recommends changing the air filter every 90 days for one-inch filters and every 12 months for four- or five-inch filters. They’re easier to use compared to accordion style filters, which have to be installed with plastic combs.

Biggest downsides: The product can only be used in residential buildings, which limits its versatility. The dimensions are also not as accurate and are not specific for certain types of filters. The slim fits are also smaller in every dimension, which can make it difficult to have a proper seal. They may also be too wide for older models of furnaces. The cardboard reinforcing is low-quality and is prone to tearing. The packaging also doesn’t clearly list a MERV rating.

Green Pick

Nordic Pure 20x25x4 (3-5/8 Actual Depth) MERV 12 Pleated AC Furnace Air Filters

The Nordic Pure 20x25x4 (3-5/8 Actual Depth) MERV 12 Pleated AC Furnace Air Filters are efficient in trapping mold, dander, dust, and pollen. The pleated design increases the lifespan of the product.

Price Check

Most notable upside: The Nordic Pure air filters have a nominal size of 20-Inch by 25-Inch by 4-Inch and an actual size of 19-1/2-Inch by 24-1/2-Inch by 3-3/4-Inch. With a MERV 12 rating, it proves to be one of the most efficient filters on the market and is designed to collect pollen, pet dander, mold, and dust in the building to prevent it from recirculating or contaminating the air. The recycled frame of the filter makes it an eco-friendly option for those who are looking to reduce their carbon footprint. The product is constructed from recycled beverage paper to ensure that it’s easier on the environment. It’s proven to outperform non-electrostatic fiberglass filters, poly disposable filters, and washable filters to make it possible to breathe easier and avoid having contact with common allergens. It also includes pleats with a large surface area to ensure more particles are collected without recirculating back into the house. The pleats that are added to the filter allow the product to last longer when compared to similar products, which means it only needs to be replaced every three to six months.

Biggest downsides: The filter is not efficient enough to remove smoke, candle soot, exhaust, smog, bacteria, and viruses, which can cause illnesses to circulate throughout the building. It is also incapable of eliminating odors.

All Our Picks

Honorable Mention

The Filtrete 20x25x4,
AC Furnace Air Filter, MPR 1550 DP,
Healthy Living Ultra Allergen Deep Pleat

The Filtrete AC Furnace Air Filter Healthy Living Ultra Allergen Deep Pleat proves it can outperform fiberglass. It improves airflow and traps pollutants with its Filtrete Brand 3-in-1 technology.

Price Check

Tips for Effective Furnace Filters

The most effective furnace filters require less changing and more particles that are smaller in sizes. Avoid selecting a product that is constructed with cheap woven fiberglass, which is only capable of screening out dirt and debris that can cause damage to the appliance. More surface area is included with accordion filters, which allows the particles to be trapped for a longer period of time without placing excess pressure on the furnace. Electrostatic filters are ideal in homes where pets are present or if a resident smokes to improve the air quality. They’re most effective when vacuuming the home frequently and with the use of a small HEPA air purifier.

Check the MERV rating before you select the right filter. The higher the MERV rating, the more particles will be trapped, although some products may be too efficient and can cause excess pressure to be placed on the furnace. Hospitals and laboratories often use filters with a MERV 12 rating, but homes and offices can benefit from a product that has a MERV 11 rating, which allows smoke, bacteria, viruses, cough debris, and odors to be trapped.

A Note About Safety and Storage

Furnace filters can be stored most effectively when they’re individually wrapped in the original packaging to prevent dust from accumulating in the months that they’re not used. Store the product in a cool, dry place that isn’t overly humid. If the product is not protected with plastic packaging, consider storing it in a sealed container or wrapping it in a sheet to protect the materials to ensure that it’s clean and in excellent condition when it’s installed. Avoid storing it on the ground where dust and dirt can accumulate.

The Best Furnace Filter 20-x-25-x-4

Your guide to this review today is by Cleaning expert Adam Barker

The Cleaning Institute

Testing Categories

Aerostar 20x25x4
MERV 11 Pleated
Air Filter

The Filtrete 20x25x4,
AC Furnace Air Filter, MPR 1550 DP,
Healthy Living Ultra Allergen Deep Pleat

Nordic Pure 20x25x4 (3-5/8 Actual Depth) MERV 12 Pleated AC Furnace Air Filters

All Our Picks

Aerostar 20x25x4
MERV 11 Pleated
Air Filter

The Filtrete 20x25x4,
AC Furnace Air Filter, MPR 1550 DP,
Healthy Living Ultra Allergen Deep Pleat

Nordic Pure 20x25x4 (3-5/8 Actual Depth) MERV 12 Pleated AC Furnace Air Filters

Tips for Effective Furnace Filters

A Note About Safety and Storage

Quick Links

Sign Up for Our Newsletter

The Best Furnace Filter 20-x-25-x-4

Your guide to this review today is by Cleaning expert Adam Barker

The Cleaning Institute

Testing Categories

Aerostar 20x25x4MERV 11 Pleated Air Filter

The Filtrete 20x25x4, AC Furnace Air Filter, MPR 1550 DP, Healthy Living Ultra Allergen Deep Pleat

Nordic Pure 20x25x4 (3-5/8 Actual Depth) MERV 12 Pleated AC Furnace Air Filters

All Our Picks

Aerostar 20x25x4MERV 11 Pleated Air Filter

The Filtrete 20x25x4, AC Furnace Air Filter, MPR 1550 DP, Healthy Living Ultra Allergen Deep Pleat

Nordic Pure 20x25x4 (3-5/8 Actual Depth) MERV 12 Pleated AC Furnace Air Filters

Tips for Effective Furnace Filters

A Note About Safety and Storage

Quick Links

Sign Up for Our Newsletter

Aerostar 20x25x4
MERV 11 Pleated
Air Filter

The Filtrete 20x25x4,
AC Furnace Air Filter, MPR 1550 DP,
Healthy Living Ultra Allergen Deep Pleat

Aerostar 20x25x4
MERV 11 Pleated
Air Filter

The Filtrete 20x25x4,
AC Furnace Air Filter, MPR 1550 DP,
Healthy Living Ultra Allergen Deep Pleat