Top-Rated Furnace Filters for Allergies, Dust, Pet Owners and More

A furnace filter is all that stands between the furnace burner and the dusty surroundings, and it also protects people from breathing contaminated air recirculated by the blower. It’s a rectangular piece of fibrous filtering material, typically mounted in a frame. There’s usually one installed in a channel behind the air intake cover on the furnace itself, and there may be others installed in return vents. The most common sizes are 16-in. x 20-in., 20-in. x 25-in. and 16-in. x 25-in., but there are other sizes available.

What to Consider When Choosing a Furnace Filter

It’s important to choose your filter wisely because a furnace with the wrong filter won’t work efficiently. A filter that removes the smallest particulate matter provides the cleanest air, but it might not provide enough airflow for the furnace.

On the other hand, furnace performance can be adjusted when clean air is the number one priority. That’s why a consultation with an HVAC technician is a must before shopping for a more efficient filter than the one you have now.

Types of Furnace Filters

Filters can be disposable or washable, pleated or non-pleated. Some are electrostatically charged to better attract pollutants. The fibers may be natural, such as cotton or cellulose; a light metal like aluminum; or a synthetic material like polyester or fiberglass.

“There is a lot of debate when it comes to furnace filters,” says Lou Manfredini, Ace Hardware’s home expert. “This is my opinion that I have been giving for 30 years: pleated filters offer better air filtration for your home in a forced air system than spun fiberglass filters. That said, I would only choose pleated filters for your forced air furnace and A/C.”

Over the years, filter efficiency has improved to provide cleaner indoor air. The Minimum Efficiency Reporting Value (MERV) rating, ranging from 1 to 20, identifies a filter’s ability to remove particulate matter. The higher the MERV, the better the filter.

Typical MERV ratings for residential furnace filters are between six and 12. If you’re concerned about indoor air quality, the Environmental Working Group recommends a MERV 10 or higher.

Furnace Filter Features

When shopping for a furnace filter, check MERV rating first. Other important factors include:

• Disposable/Washable: Homeowners tend to prefer throwaway filters, which means keeping extras on hand. A washable filter, on the other hand, can last for years, but washing can be time-consuming. If you use disposable filters, “they should be changed every one to two months,” says Manfredini. “If you use one-inch filters in your home, then change them every month when running your system. The thicker media filters can be changed every two to three months.”
• Pleated/Non-Pleated: Non-pleated filters with fiberglass or polyester fibers are inexpensive and provide good airflow for the furnace. But to keep the air in your house clean, you’ll need the extra filtration area of a pleated filter.
• Thickness: Most filters are one inch thick, but some can be two to five inches. Thicker filters provide better filtration, but they don’t fit every system.
• Electrostatic: Most small particles in the air carry an electric charge. Electrostatic filter media attract and remove these more easily than uncharged media.
• MPR: This is the Microparticle Performance Rating established by 3M. It ranges from 600 to 2,800 — the higher the number, the better the filtration. Most residential filters range from 1,200 to 1,900.