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A furnace filter provides protection for your HVAC system, while also enhancing air quality inside your home. Made from various fibers, including fiberglass, polyester, or cotton, these air filters work by capturing particles like dust, dirt, and dander that would otherwise clog up your furnace or settle in your ductwork.
There are many types of furnace filters to choose from, depending on your objectives for air quality and how often you want to replace the filter—if ever. Most furnace filters are disposable but permanent furnace filters are an option as well, if you’re willing to periodically clean the air filter. The filter material plays a role in the lifespan of the filter and determines how efficient the filter is at capturing particles. To find the right filter for your needs, the industry-standard rating system is MERV. It ranges from 1 to 20, with average residential furnace filters receiving MERV scores between 5 and 10.
Best Overall: Filtrete Allergen Defense
Size: 16 x 20 x 1 inches | FPR Rating: Not available | MERV Rating: 11 | Air Filter Depth: 1 | Filter Material: Electrostatically charged filter media
MPR 1000 rating
Permanent electrostatic charge attracts dust particles
Receive app reminders when it’s time to replace
30-day replacement schedule
A high-quality furnace filter can dramatically reduce dust, allergens, and other particles floating in the air, and the popular Filtrete Allergen Defense is a great choice. This furnace filter has MERV 11 rating, which means it filters out more than 90 percent of particles between 1 and 3 microns in size. It’s best suited for filtering dust, pollen, and pet dander and will also filter smoke and smog. According to ASHRAE standards, a MERV 11 filter would fall into the ‘Superior Residential’ category.
The filter is constructed of electrostatically charged filter media, which means the fibers inside the filter cartridge have been charged to attract and hold onto dust and other particles. Like many 1-inch furnace filters, it’ll need replacing every 30 days or so. To help you keep track, use Filtrete’s Smart app. You can scan the barcode on the package, set a replacement interval, and then receive a reminder when the filter life expectancy has run out.
Best Pleated: Honeywell Elite Allergen Pleated FPR 10 Replacement Air Filter
Size: 16 x 25 x 1 inches | FPR Rating: 10 | MERV Rating: 13 | Air Filter Depth: 1 | Filter Material: Proprietary
Lasts up to 90 days
Filters particles as 0.3 microns
More expensive than other pleated filter options
Pleated furnace filters provide more surface area for filtering out contaminants and are a popular alternative to conventional fiberglass furnace filters. This Honeywell Home Elite Allergen Pleated Air Filter has an FPR 10 and MERV 13 rating, indicating that it’s useful for filtering out large and small particles. It’s capable of catching virus carriers, bacteria, smoke, dust, dander and other common contaminants. Compared to a typical 30-day lifespan for fiberglass or synthetic flat filters, this pleated filter lasts up to 90 days before needing replacement.
Best Disposable: Filtrete Basic Dust and Lint Air Filter
Size: 20 x 20 x 1 inches | FPR Rating: Not Available | MERV Rating: 5 | Air Filter Depth: 1 | Filter Material: Electrostatically charged filter media
MERV 5 rating
May require replacement sooner than 90 days
Limited MPR 300 rating
Furnace filters catch dirt and debris that might otherwise find its way into your HVAC system, leading to part failure, dirty ducts, and worsened air quality. You should always have a furnace filter installed in your home, even if it’s an affordable, disposable furnace filter like the Filtrete Basic Dust and Lint Air Filter.
Designed to be quickly installed and easily disposed of after the filter’s 90-day lifecycle, this furnace filter captures particles between 3 and 10 microns in size. As the name suggests, the Filtrete Basic Dust and Lint Air Filter is best suited for reducing household dust, lint, and dust mite debris. It has a rather low MPR 300 rating, which means it won’t capture as many microparticles as more advanced furnace filters. However, the MERV 5 rating qualifies this filter as a step-up from the most basic furnace filters available.
Best for Allergies: Filtrete Healthy Living Ultimate Allergen Air Filter
Size: 16 x 25 x 1 inches | FPR Rating: Not available | MERV Rating: 13 | Air Filter Depth: 1 | Filter Material: Synthetic
MERV 13 rating
Certified for allergen reduction
Higher cost per filter
A high-quality furnace filter designed to filter small particles can remove many allergens from the air and provide a measure of relief to allergy-sufferers. The Filtrete Healthy Living Ultimate Allergen filter has a MERV rating of 13, placing it in a class of filters designed to capture particles as small as 0.30 to 1.0 microns in size.
Certified by the Asthma and Allergy Foundation, this furnace filter captures common irritants like dust, pollen, and dander, along with smaller particles such as smoke, bacteria, and cough or sneeze particles. If you’re shopping for a furnace filter for allergies, you should also consider the MPR rating. The higher the number, the greater the amount of particle the filter can capture. The Filtrete Healthy Living Ultimate Allergen filter has an MPR rating of 1900.
Best Permanent: K&N HVAC Air Filter
Size: 20 x 25 x 1 inches | FPR Rating: Not Available | MERV Rating: 11 | Air Filter Depth: 1 | Filter Material: Synthetic polymer
Lasts for years
Loose fit in some HVAC systems
Recommended to use K&N filter cleaning solution
A permanent furnace filter solves one of the greatest struggles with HVAC maintenance—remembering to buy new filters. K&N has made a name for itself in automotive air filters and brings this expertise to home HVAC systems with this permanent furnace filter. It’s made with synthetic polymer filtration media that won’t break down or degrade, even after many months of use.
With a MERV 11 rating, this filter is a good choice for most residential homes. It filters particles between 1.0 and 3.0 microns in size. The filter can (and should) be regularly cleaned for best performance and a long life of service. K&N recommends using their air filter cleaner solution and then rinsing with a low-pressure hose.
Best for Odors: Arm & Hammer Enhanced Allergen and Odor Control Air Filter
Size: 16 x 25 x 1 inches | FPR Rating: 6 | MERV Rating: 8 | Air Filter Depth: 1 | Filter Material: Synthetic
Electrostatically charged filter
Unscented odor-fighting design
Doesn’t provide filtration for smoke
A furnace filter benefits your HVAC system, but your nose will thank you if you opt for an odor-reducing filter, like this option from Arm & Hammer. The Enhanced Allergen and Odor Control furnace filter has a MERV 8 rating and FPR rating of 6, meaning it filters out contaminants like dust, pollen, mold spores, and dander.
It’s especially recommended for pet owners looking to reduce odors, but this filter is a good choice for any household since it captures odor-causing particles from cooking, smog, and more. Instead of cloaking odors with scents, this unscented furnace filter traps particles in pleated filtration media to improve air quality. Each disposable filter lasts for up to 90 days.
Best Long Life: Honeywell Home Pleated Air Filter, 4-inch
Size: 20 x 25 x 4 inches | FPR Rating: 8 | MERV Rating: 8 | Air Filter Depth: 4 | Filter Material: Polypropylene
Electrostatically charged filter
Lasts up to 12 months
May not offer enough filtration for allergy-sufferers
Also known as annual furnace filters, long life furnace filters have more surface area to stretch the time between filter replacements. While many 1-inch filters need replacement every 90 days or so, a 4-inch furnace filter, like the Honeywell Home Pleated Air Filter, lasts for up to a year.
This pleated furnace filter is made with polypropylene filtration media. It has a MERV 8 rating and is electrostatically charged to attract and capture large particles such as dust and pollen, as well as smaller particles like mold, smoke, and other odor-causing particles.
Best Budget: Rheem Basic Household Pleated FPR 4 Air Filter
Size: 20 x 20 x 1 inches | FPR Rating: 4 | MERV Rating: 8 | Air Filter Depth: 1 | Filter Material: Not available
Filters dust, pollen, dander, and more
Affordable, easy filter changes
Won’t capture small or microscopic particles
Cardboard frame can be flimsy
Regularly changing your filter furnace is important for maintaining air quality in your home and efficient operation of your HVAC system. A budget furnace filter, like this option from Rheem, provides an affordable way to keep up with this important home maintenance task.
The Rheem Basic Household Pleated Air Filter is made of proprietary filter media, backed by wire. It carries a MERV 8 rating and is capable of capturing contaminants like dust mites, pet dander, dust, and pollen from the air. This filter isn’t the best choice for allergy-sufferers or if you’re shopping for ultrafine filtration, since it’s only equipped to capture larger particles. However, these budget furnace filters cost only a few dollars each and require replacement every 90 days. Your best bet is to buy a pack of multiples and keep a replacement filter ready.
Best Washable: True Blue Budget Washable Filter
Size: 23.75 x 35.75 x 0.75 inches | FPR Rating: 2 | MERV Rating: 4 | Air Filter Depth: 1 | Filter Material: Synthetic
Lasts up to 1 year
Can be cut to fit your furnace
Low FPR and MERV rating
Unlike disposable options that may require monthly replacement, a washable furnace filter like this option from True Blue can be rinsed and reused for up to a year. Made of non-pleated synthetic fibers, this frameless furnace filter can be cut to fit your system. It has a MERV 4 rating, which is basic but sufficient for collecting dust, dirt, pollen, and other large particle items.
Our top recommendation for a furnace filter is the Filtrete Allergen Defense (view at Amazon). This air filter offers better-than-average particle capture, as indicated by its MERV 11 rating. It’s an electrostatically charged filter, so it attracts and retains dust and other particles. On the other hand, if you’re only concerned with capturing large particles for the sake of your HVAC system’s longevity, then the affordable Rheem Basic Household Pleated Air Filter (view at Home Depot) makes a budget-friendly choice. These filters have a MERV 8 rating and are frequently bought in a multi-pack.
What to Look for in a Furnace Filter
Air Filter Type
There are several types of both disposable and permanent furnace filters to consider. Disposable filters typically last between 30 days and 90 days, though some options can last 6 or 12 months. The most basic disposable furnace filters are made of fiberglass and only capture larger dirt and dust particles. Other options include synthetic filter media with enhanced ability to trap air contaminants.
Permanent furnace filters are intended to last for many years, with regular maintenance. This type of furnace filter must be washed and rinsed thoroughly to clear the filter of contaminants.
Both disposable and permanent furnace filters include electrostatic filter options. These filters have media (usually cotton or paper) that has been permanently charged to attract dust and other particles.
To make it easier to compare the effectiveness of one filter versus another, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers—known as ASHRAE—developed the MERV rating system.
Furnace filters range from a MERV rating of 1 to 16. MERV 1 is the most basic filter that only filters particles larger than 10 microns in size, while MERV 16 filters capture particles as small as 0.30 to 1.0 micron in size.
For basic residential needs, you may only need a filter with a MERV rating of 1 to 4. However, the better choice for most homes is a MERV 5 to 8 filter. For enhanced air quality and reduction of allergens, look for a MERV 9 or better filter.
Filter Performance Rating
A filter performance rating, also known as FPR, is a separate rating system developed by Home Depot. It factors in a filter’s ability to capture large particles, small particles, and weight gain from particle capture over the filter’s lifetime. It assigns filters a score ranging from 1 to 10 and uses tiers of good, better, best, and premium to help buyers find the furnace filter that fits their needs.
Filter Material: A number of materials are commonly used for furnace filter material, including fiberglass, cotton, polyester, and other synthetic fibers. Furnace filters with fiberglass are typically the least expensive, disposable filter option. They offer minimal air resistance, which places less strain on HVAC systems but captures only large particles. On the other hand, pleated furnace filters made from cotton paper or synthetic fibers offer greater filtration capabilities but may restrict airflow to the system. Some furnace filters made from cotton or synthetic fibers are washable.
How thick should your furnace filter be?
The most common size is a 1-inch thick furnace filter, but there are also thicker 4 and 5-inch filter options. Thicker filter furnaces usually have a longer lifespan and offer lower static pressure for the system. Whether or not a thicker furnace filter will fit in your system depends on how the cabinet is configured. You should check your HVAC cabinet for the recommended size of furnace filter.
How often should furnace filters be changed?
All disposable filters have a replacement schedule recommended by the manufacturer, but how often you should replace your furnace filter depends on use and lifestyle factors. Most filters require replacement every 30 to 90 days. However, if you increase the particle load within the air, due to having pets, leaving the windows open, frequently burning candles, or other activities, you may notice that your filter becomes dirtier and requires replacement more quickly.
Can you clean a furnace filter?
Disposable furnace filters cannot be cleaned and used effectively beyond their expected lifetime. However, washable furnace filters can be cleaned. The specific maintenance required varies by type and according to the manufacturer’s instructions, but typically low-pressure water and perhaps a mild cleanser are all that is necessary to clear contaminants from the filter.
Are furnace filters recyclable?
In most cases, a furnace filter is not recyclable, due to the fiberglass or synthetic filter media commonly used. The best way to dispose of a used furnace filter is typically in the garbage. If you’re concerned about reducing waste, consider a washable or permanent furnace filter.
Why Trust The Spruce?
Erica Puisis researches the best home improvement and lifestyle products that make life easier and better. Areas of expertise include home appliances and systems. For this roundup of the best furnace filters, Erica considered the most popular filters from leading brands like 3M Filtrete and Honeywell Home. She evaluated each filter based on available MERV, MPR, and FPR ratings. All of the filters on this list, except for one, have at least a MERV 5 rating. We’ve included both disposable, washable, and permanent furnace filter options.