Changing your furnace’s air filter every three months can keep it from malfunctioning while contributing to better indoor air quality and reducing energy costs. You should replace your filter in conjunction with the change in seasons as regular maintenance ensures the filter won’t become clogged with dust, pet hair, and other airborne particles, which can reduce the furnace’s efficiency.
Keep reading to learn everything you need to know about choosing the best furnace filter for your system and to find out why we’ve chosen the following replacement filters as some of the top choices for most homeowners.
- BEST OVERALL: Filtrete AC Furnace Air Filter, MPR 1500
- RUNNER UP: Nordic Pure MERV 12 Pleated AC Furnace Filters
- BEST BUDGET: FilterBuy MERV 8 Pleated AC Furnace Air Filter
- BEST SMART: Filtrete Smart AC Furnace Air Filter
- BEST FOR ALLERGIES: AIRx ALLERGY MERV 11 Pleated Air Filter
- BEST FOR PETS: Aerostar Allergen & Pet Dander MERV 11 Air Filter
- BEST FOR MOLD: Filter King MERV 8 Filter With Mold Protection
- BEST FOR CIGARETTE SMOKE: NaturalAire Odor Eliminator with Baking Soda
- ALSO CONSIDER: Honeywell Home MicroDefense AC Air Filter
Types of Furnace Filters
As far as home improvement gear goes, furnace filters may rank among some of the least exciting products. There’s none of the danger and raw efficacy of power tools, none of the visual impact of perfectly mitered crown molding, and certainly none of the reassurance that accompanies significant investments like new windows or new roofing.
But there can be a big impact even in little things, and finding the right furnace filter can save money and improve air quality. Originally, filters were designed to protect the moving parts of the furnace itself. Still thanks to technological advancements, filters now prevent harmful particles from cycling back into the air that you breathe at home.
Furnace filters are rated by their minimum efficiency reporting value, or “MERV.” The higher the rating, the more efficient the filter is at trapping airborne particles. The numerical range is from 1 (lowest efficiency) to 20 (highest efficiency). Read more about MERV ratings below.
Disposable Fiberglass
A disposable fiberglass filter is the option that comes to mind when you think “furnace filter.” Created from 1-inch thick spun fiberglass, it does little more than prevent larger particles like dust, lint, and debris from gunking up your system. They have MERV ratings of 2-3 and cost just $1 to $2. Though they are very inexpensive and good for renters and those without allergies or asthma, they have little to no effect on cleaning the air.
Disposable Pleated
Disposable pleated air filters, a popular option made from polyester or cotton paper, can remove some small particles like spores and mites for better air quality, but need to be changed frequently to avoid clogging and taxing your HVAC system.
These options have a MERV rating of 6 and cost $4 to $5. While relatively inexpensive, they are also made from green materials and block some small particles. But, they can add more resistance to airflow, making your system more expensive to operate.
High-Efficiency Pleated
The granddaddy of furnace filters, high-efficiency pleated options are made from deep 4- to 5-inch thick pleated synthetic cotton attached to a very rigid metal grid to prevent leaks or fluttering. These filters are a little pricey at $100, but they have an excellent MERV rating of 14-16 making them suitable for use in hospitals.
Using one at home may be difficult since they are typically used in special housing due their thickness. But, they can screen out the smallest of particles and are beneficial for those with respiratory problems or autoimmune disorders.
Disposable Electrostatic
A disposable electrostatic filter contains self-charging electrostatic cotton or paper fibers that attract and trap small particles. With a MERV rating of 10, these options are affordable in standard sizes and are a good solution for homes with children, pets, or smokers. If needed, custom sizes are expensive, leading to higher costs if replaced regularly over several years.
Reusable Electrostatic
Similar to their disposable counterpart, a reusable electrostatic filter contains self-charging cotton fibers that attract particles. Permanent options have a removable, machine-washable furnace filter you can reuse for six to eight years. With a MERV rating of 8, these produce little waste, are more effective than pleated air filters, and a good option if you use a standard size. But, they are less effective than electrostatic models, and custom sizes are expensive.
Polyester
This reusable filter is denser than fiberglass, so it blocks more airborne particulates, and it comes in either a flat or pleated version in thicknesses up to four inches. Traps up to 91 percent of common airborne particles, including pollen and dust particles with a MERV rating of 8. As for the downside, these options do not eliminate the need to clean HVAC filters or coils at least every few years because some of the particles will still slip through.
HEPA
A high-efficiency particulate air (HEPA) filter blocks up to 99.7 percent of airborne particles that are 0.3 microns and larger, but it isn’t readily available in sizes to meet standard furnaces.
Because HEPA filters are so dense, they can reduce airflow into the furnace, so like high-efficiency pleated air filters, they’re typically used only in commercial furnaces or hospital settings. Though these picks block the highest level of airborne particulates and provide better air quality with a MERV rating of 16-20, they are not suitable for most residential furnaces.
What to Consider When Buying a Furnace Filter
Choosing the best furnace filter requires matching the filter to the furnace manufacturer’s specifications. Just because one filter blocks more particles than another doesn’t mean it’s the right choice for your furnace.
Filter Size
Furnace filters come in dozens of sizes, with 16-by-20-inch, 20-by-25-inch, and 16-by-25-inch being the three most common sizes. Filter thickness varies from one to five inches, and in general, the thicker the filter, the more particle-blocking ability it will have. Before choosing a filter, you’ll need to check the owner’s or operating manual, because not all furnaces will accept a thicker product. As the filter gets thicker, the furnace must work harder to pull air through it, reducing its efficiency and useful life.
Washable vs. Disposable
Changing your furnace’s filter regularly (every three months is ideal) will help keep dust and other particles from damaging the furnace’s working parts, such as its heating coils and fan. Disposable filters are lightweight, relatively inexpensive, and can be tossed out after using. Washable filters feature a heavier aluminum frame with electrostatic fibers that serve as the filter. A washable filter, depending on the brand, may last a few years. Still, it requires a specific washing procedure, which may include separating the filter into layers and washing them separately. You must also make sure a washable filter is completely dry before reinstalling it to prevent mold and mildew growth. For many, using disposable filters is the quickest and most straightforward solution.
MERV Rating
Furnace filters are assigned a minimum efficiency reporting value (MERV) based on their density. While denser filters trap more airborne particles, they should also be changed more frequently because they tend to clog more quickly. The MERV scale runs from 1 to 20, and filters in the 6 to 12 range are designed for residential use. Your furnace’s operating manual will recommend the MERV rating that’s best suited to your unit. Higher efficiency filters are mainly used in commercial settings and health facilities where the HVAC system is powerful enough to draw air through a dense filter easily.
Climate
Where you live can factor into the type of furnace filter that’s best for your home. In humid rainy areas, mold growth is a common concern, so if you live in a damp region, you’ll want to choose a furnace filter with a MERV rating of at least 6 in order to block mold spores from being drawn into the furnace and then recirculating inside your home.
Our Top Picks
The best furnace filter should protect the working parts of your furnace and trap dust, pet dander, and pollen to keep these airborne pollutants from recirculating in your home. Consult your furnace’s operating manual to determine the recommended thickness and MERV rating and then check out the following replacement filters at the top of their class. One is sure to be a good fit for your furnace.
Photo: amazon.com
Available in more than a dozen sizes, the Filtrete AC Furnace Air Filter comes in as our best overall furnace replacement filter. Its high-efficiency MERV-12 rating makes it an excellent choice for homeowners who want to trap as much airborne debris as possible.
Filtrete uses exclusive 3-in-1 technology to trap lint, dust, pet dander, soot, pollen, and mold spores while encouraging fresh air to flow through the filter. The 1-inch thick AC furnace filter is narrow enough to fit in most wall registers and in many slide-in filter holders located directly on the furnace itself. Measure your filter before ordering to get an exact fit.
Product Specs
- Type: Disposable electrostatic
- Size: 20 inches by 25 inches by 1 inch
- MERV Rating: 12
Pros
- Comes in many sizes
- 3-in-1 technology; traps lint, dust, pet dander, soot, pollen, and mold
- Compatible with multiple wall registers
Cons
- Does not filter exhaust particles
Photo: amazon.com
Changing furnace filters is a snap with Nordic Pure MERV 12 Pleated AC Furnace Filters that block a high level of dust and other airborne pollutants that could otherwise end up in the furnace or recirculating throughout your home. These disposable pleated filters are hypoallergenic and feature electrostatic fibers that attract pollutants, and they resist mold and mildew growth.
These AC furnace filters are one-inch thick and come in a variety of sizes. Because these filters offer a high MERV rating of 12, they may clog more quickly than filters with lower scores. Depending on how often your furnace runs, you may need to replace them more often than every three months.
Product Specs
- Type: Disposable pleated
- Size: 16 inches by 16 inches by 1 inch
- MERV Rating: 12
Pros
- Hypoallergenic design
- Electrostatic particles included; mold and mildew-resistant
- Comes in multiple sizes
Cons
- May clog faster than comparable options; frequent replacement may be required
- Pricey
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You don’t have to spend a lot of money to get a quality furnace filter. With a FilterBuy MERV 8 Furnace Filter, you can choose from a variety of filter sizes and thicknesses ranging from one to four inches, making FilterBuy a versatile and economical option.
This electrostatically-charged filter will trap up to 90 percent of airborne particles, including lint, pet dander, and pollen to keep your furnace running clean for up to three months before you need to replace it. For added convenience, this filter has arrows on its frame to help identify the direction of the airflow/which direction you should place the filter in your unit.
Product Specs
- Type: Disposable electrostatic
- Size: 12 inches by 20 inches by 2 inches
- MERV Rating: 8
Pros
- Comes in multiple sizes and thicknesses
- Traps 90 percent of airborne contaminants
- Lasts for up to 3 months
- Arrows included on frame; directs airflow and placement
Cons
- Does not filter smoke or bacteria
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Photo: amazon.com
Available in dozens of sizes and with Bluetooth technology to monitor your filter use, the Filtrete Smart AC Furnace Air Filter is a top choice for a furnace replacement filter. With a proprietary algorithm that detects airflow to track usage of your filter, users can worry less about changing the filter at the right time.
The high-efficiency MERV-12 rating makes this AC furnace filter an excellent choice for homeowners who want to trap as much airborne debris as possible. Filtrete uses exclusive 3-in-1 technology to trap filter media like lint, dust, pet dander, soot, pollen, and mold spores. The 1-inch thick filter is narrow enough to fit in most wall registers or many slide-in filter holders. Download the Filtrete app to monitor and receive alerts about the filter status.
Product Specs
- Type: Disposable electrostatic
- Size: 12 inches by 12 inches by 1 inch
- MERV Rating: 12
Pros
- Comes in many size options
- Bluetooth-enabled; monitoring through Filtrete app
- Traps lint, dust, pet dander, soot, pollen, and mold spores
Cons
- Does not filter ultrafine particles
- Pricey
Photo: amazon.com
Available in 1-inch thickness and a host of sizes, the disposable, pleated, AIRx ALLERGY MERV 11 Pleated Air Filter is designed with extra density to trap airborne allergens that can trigger allergy symptoms. It’s also good at blocking smoke and odors.
The MERV 11 filter is dense and helps keep allergens from recirculating through your home’s ductwork. For the best air quality, use this filter in conjunction with other allergen-reducing measures, such as a vacuum with a HEPA filter and an air purifier to keep airborne allergens at bay.
Product Specs
- Type: Disposable pleated
- Size: 16 inches by 20 inches by 1 inch
- MERV Rating: 11
Pros
- Comes in multiple sizes
- Suitable for those with allergies
- Built-in HEPA filtration and air purifier
- Comes with 6 pleated furnace filters
Cons
- Does not filter smoke or virus carriers
- Expensive price point
Photo: amazon.com
If you have pets, check out the disposable, pleated, Aerostar Allergen & Pet Dander MERV 11 Air Filter that blocks a high number of airborne particles, including pet fur and pet dander. This high-efficiency, electrostatic filter attracts particles and traps them in place.
It is available in a range of sizes and thicknesses from one to four inches, making it an excellent choice for a variety of furnaces and return-air vent compartments. The Aerostar manufacturer recommends changing this filter every two to three months in the fall and spring, and monthly during heavy furnace use, such as in winter.
Product Specs
- Type: Disposable pleated
- Size: 16 inches by 25 inches by 1 inch
- MERV Rating: 11
Pros
- Comes in multiple sizes
- Lasts for 2-3 months
- Comes with 6 pleated furnace filters
Cons
- Does not filter bacteria
- Some users report that the filters are not true to size
Photo: amazon.com
If you live in a humid region, consider the Filter King MERV 8 Filter with Mold Protection that’s designed to trap pollutants, including mold spores, yet allow free airflow through the filter to reduce the risk of mold or mildew growth.
This disposable pleated filter is available in a variety of 1- and 2-inch thick sizes to fit a wide range of furnaces. The manufacturer recommends replacing it once every three months at a minimum. Meant for residential or commercial use, these filters also trap auto emissions ,humidifier dust, and legionella. But, this option is not the best when it comes to tobacco smoke, bacteria, virus carriers, and microscopic allergens.
Product Specs
- Type: Disposable pleated
- Size: 30 inches by 30 inches by 1 inch
- MERV Rating: 8
Pros
- Suitable for residential and commercial use
- Filters auto emissions, humidifier dust, and legionella
- Lasts for up to 3 months
- Affordable price point
Cons
- Comes in 1 size
- Does not filter tobacco smoke, bacteria, virus carriers, and microscopic allergens
Photo: amazon.com
Whether your home has a wood-burning fireplace or the chef of the family tends to scorch meals regularly, the NaturalAire Odor Eliminator with Baking Soda Filter will help neutralize that smell of smoke and other lingering odors.
The 1-inch thick, disposable pleated filter absorbs smells and eliminates unwanted odors while trapping other airborne particles, such as dust and pollen. The filter comes in a variety of sizes and should be changed a minimum of once every three months. Affordable and long-lasting, this option has a MERV rating of 8 and comes with 4 filters with V-shaped pleats for a larger surface and added air flow.
Product Specs
- Type: Disposable pleated
- Size: 20 inches by 20 inches by 1 inch
- MERV Rating: 8
Pros
- Odor-control capabilities
- Filters and traps dust and pollen
- Comes in multiple sizes
- 4 pleated furnace filters included
Cons
- Comes in 1 size
- Some users report manufacturing defects
Photo: homedepot.com
If you’re looking for a longer-lasting filter, check out the Honeywell Home MicroDefense AC Air Filter that lasts up to 12 months before needing to be replaced. This disposable, 4-inch thick filter features deep pleats and electrostatically charged fibers that capture and hold a large amount of particles in its crevices.
The filter is only available in 2 sizes, the dimensions of 16 inches by 25 inches by 4 inches and 20 inches by 20 inches by 1 inch, so measure your current filter to make sure the Honeywell extended use filter will fit. Plus, this filter can help provide odor control.
Product Specs
- Type: High-efficiency pleated
- Size: 16 inches by 25 inches by 4 inches
- MERV Rating: 8
Pros
- Long-lasting; works for 12 months
- Comes in 2 size options
- Odor-control included
Cons
Our Verdict
With so many options available, finding the right furnace filter can be difficult. One of the best options overall is the Filtrete furnace filter with its disposable electrostatic design, multiple size options, MERV rating of 12, and 3-in-1 technology to trap lint, dust, pet dander, soot, pollen, and mold.
Alternatively, if you are interested in a more budget-friendly pick, the FilterBuy furnace filter also has a disposable electrostatic design, but has a MERV rating of 8 which can trap 90 percent of contaminants and filter media.
How We Chose the Best Furnace Filters
We researched the most sought-after furnace filters in their respective categories and discovered that the best options available are compatible with many HVAC system and furnace brands, filter out as many pesky particles and contaminants as possible, have a long lifespan, and come with a high MERV rating.
The favored type of furnace filters in the above list is the disposable pleated and electrostatic for their ability to filter out lint, dust, pet dander, soot, pollen, and mold spores. While many picks are not capable of filtering smoke and bacteria, most of these options come in multiple sizes and thicknesses to be compatible with your furnace. As for MERV ratings, most of the products above range from 8-12 without impeding airflow.
Select picks listed above can last for over 2-3 months at a time, but for convenience, some will last for over 12 months or come with multiple filters. As for special features, arrows on the frame to direct placement and airflow, odor-control, HEPA filters, and even Bluetooth capability are included for convenience.
FAQs
With a variety of furnace filters on the market, all promising to do a great job of trapping airborne particles, it’s only natural to have some questions about the best furnace filter for your home.
Q: What is the best MERV rating for furnace filters?
While MERV ratings go all the way up to 20, high-rated filters are generally reserved for health and research facilities. For residential furnaces, a rating of 12 is about the best.
Q: Do higher MERV ratings decrease airflow?
Higher MERV ratings will often cause a more restricted airflow. However, the restrictions do not cause a significant impact when used in residential settings.
Q: Is a thicker furnace filter better than a thinner one?
Not always. Thicker filters are denser and block more dust and particles, but they may also cause the furnace to work harder to draw in air. Use only the type and thickness of filter recommended by the furnace’s manufacturer.
Q: What is the best type of furnace filter for viruses?
According to a CNN article, HEPA filters with MERV ratings of 17 to 20 are best for reducing the spread of viruses, but most household furnaces cannot draw air through a dense HEPA filter.
Q: How often should you change your furnace filter?
Many furnace filters need to be changed every 2-3 months, which is why many options come with 4-6 filters per purchase. However, select options can last from 9-12 months before requiring a replacement.