Best Furnace Filters of 2020 – Ultimate Guide

| Last Updated: April 19, 2021

It is no secret that the air around us is plagued with pollutants, allergens, and microbes that put us at risk of not only respiratory problems but also hypersensitive reactions and allergies. 

This is where the best filter comes in handy; it takes care of the airborne particles and improves air quality. It also makes sure that your HVAC system experiences no malfunctioning due to the particles hindering air circulation.

However, purchasing the wrong filter can be quite costly and can put your health at risk too. To help you with that, here’s a buying guide of the best furnace filters that you should definitely check out. It has all that you need to know in order to find the ideal pick for your furnace. 

Our Top Picks for Furnace Filters

  • 3-in-1 technology
  • Captures large particles
  • Unique design
View Latest Price →
  • Long-lasting
  • Made in US
  • Better air quality
View Latest Price →
  • Best for the Money
  • Superior filtration
  • Increased convenience
View Latest Price →

Comparison of the Best Furnace Filters

IMAGEPRODUCT
  • Features 3-in-1 technology for deep filtering
  • Able to capture large particles, including mold spores
  • Unique design eases quality control of indoor air
View Latest Price →
  • Lasts for 3 months for easy maintenance
  • Domestically built ensuring top quality materials
  • Captures up to 90% airborne small and large particles
View Latest Price →
  • Best for the Money
  • Crafted with electrostatically charged materials to capture allergens
  • Easy to install and extremely cost-effective
View Latest Price →
  • Best Air Filter For Home Furnace
  • Twenty times more effective than fiberglass filters
  • Instantly captures bacteria, mold, dust, pollen, and others
View Latest Price →
  • Best Washable Furnace Filter
  • Made with anti-microbial materials to stop bacteria growth
  • High capacity retention for dust and other contaminants
View Latest Price →
  • Best Furnace Filter For Dust Control
  • Significantly reduces the amount of dust in the entire house
  • Easy to insert in the bottom of the register
View Latest Price →
  • Best Furnace Filter For Allergies
  • Hypoallergenic and anti-microbial properties ideal for any needs
  • Removes pet dander, including skin cells and fur
View Latest Price →

What is a Furnace Filter? 

A furnace filter is essentially a thin film installed in your furnace that traps particles present in the air. Whether you have a commercial furnace or a residential one, a filter will be installed in it. Similarly, whether you have an electric or gas furnace, you will find that it comes fitted with a filter. 

Depending on their efficiency, furnace filters can also help to capture different allergens, such as pollen and pet dander. Higher-end units that are more technologically advanced can also prevent the circulation of germs. 

What Purpose Does a Furnace Filter Serve? 

Despite being small and not blatantly apparent, a furnace filter is quite essential and is responsible for two main things. These include:

Protecting Your Furnace

The furnace filter's primary purpose is to protect the furnace and its parts, particularly the blower fan, from pollutants that the return duct takes in, such as dust, hair, airborne allergens, and debris. 

Keeping the parts clean ensures that they last longer and that your furnace continues to function optimally. 

Dealing With Contaminated Air

These days, a common problem is air contaminated with dust particles, pet dander, allergens, and other small particles. While a furnace filter is not mainly designed to clean the air, it can help to improve the air quality of your home to keep your breathing health in check. 

FilterBuy Merv 8

Characteristics of Our Favorite Furnace Filters

Our carefully formulated list features some of the best products available on the market. All of them have some common features, which makes them stand out to us. These include:

High MERV Rating

MERV refers to the Minimum Efficiency Reporting Value and is a measure of the filter's effectiveness at trapping harmful particles. As the MERV rating increases, the filter becomes more efficient. In fact, the best filters are those whose MERV rating lies between 8 and 13. The furnace filters mentioned on our list come with a good MERV rating. 

Good MPR Rating 

Microparticle Performance Rating or MPR is another measure of the filter’s effectiveness and efficiency at removing particles smaller than one micron. Generally, filters have an MPR rating between 300 and 2800; the higher the value, the superior the performance. 

SFP Filters Merv 8

The MPR in our favorite models isn’t so high that it starts lowering efficiency. Rather, our favorite furnace filters come with a good MPR rating that ensures effective filtering and great HVAC performance. 

Maintains Air Quality

Our favorite furnace filters ensure a safe and clean breathing environment for people inside the home by maintaining good indoor air quality. According to the EPA, the air within the home can be polluted more than the air outside. Our favorite furnace filters not only keep the air inside the house clean but also help to protect the respiratory health of people living within. 

Quick Take: Best Furnace Filters

These are our recommendations for the best furnace filters:

  1. Filtrete MPR 300
  2. FilterBuy Merv 8
  3. Aerostar Home Max Merv 13

Review of the Best Furnace Filters 

With the plethora of furnace filters available in the market, you might find yourself confused as to which one to go for. To make sure you buy one that keeps your furnace working effectively, here is a list of the best furnace filters that you should definitely check out. 

Best Overall:
Filtrete MPR 300

Filtrete 16x20x1, AC Furnace Air Filter, MPR 300, Clean Living Basic Dust, 6-Pack (exact dimensions 15.69 x 19.69 x 0.81)

PROS

  • Has a Microparticle rating of MERV 5
  • Suitable for your air conditioner, furnace, or HVAC system
  • Unique three-in-one technology from 3M ensures cleaner airflow
  • Non-electrostatic and washable filter that outperforms fiberglass 
  • Able to capture particles, including household dust, lint, mold spores, and dust mite debris

CONS

  • No cross bracing to prevent the filter from bowing

What Recent Buyers Report

Recent buyers have found the Filtrete MPR 300 to be a good-quality filter that has greatly improved their homes' air quality. These filters not only managed to catch dust and allergens but pet hair as well. Buyers also consider the price of this unit fair as compared to other products. 

Why it Stands Out to Us

The unique electrostatically-charged design of the Filtrete filters attracts and traps all unwanted particles from your air, providing you with clean air to breathe. These filters can be used in heating and cooling systems. They help maintain clean airflow and prevent stress on the system. 

Another thing that we like about these filters is that they help reduce the amount of energy required to achieve the desired indoor temperatures, which, in turn, helps users to save money on energy costs.    

Bottom Line 

It is vital to breathe in clean air, and with the Filtrete filters, you can create a healthier, fresher, and cleaner home environment. This filter proactively captures allergens, viruses, dust, and bacteria from your household air to ensure cleaner air for you to breathe. 

FilterBuy 16x25x1 Air Filter MERV 8, Pleated HVAC AC Furnace Filters (4-Pack, Silver)

PROS

  • Can last up to three months
  • Ideal for commercial and residential use
  • Able to withstand exposure to dampness
  • 12 pleats per foot provide a greater surface area
  • Filter frames are designed with a strong beverage board

CONS

  • Size may be a bit smaller than advertised

What Recent Buyers Report

Most buyers are immensely satisfied with this product. They had no trouble fixing it in the air filter slot. Many also reported that since they have started using this filter, they have enjoyed a deep sleep and awoke clear-headed. Moreover, its MERV 8 rating protects their furnace from overworking.  

Why it Stands Out to Us

We find the design of this unit truly extraordinary. It is long-lasting and of high quality and provides you with clean air so that you can breathe better. Its frames are constructed with a beverage board that stays strong through temperatures and humidity of up to 200°F while the pleats ensure a larger surface area to trap a large number of particles from the air. 

This efficient filter is much better than fiberglass and is able to last longer. Moreover, by replacing it often, you can keep the energy costs low. 

Bottom Line 

With this MERV 8 filter from FilterBuy, you can greatly improve the indoor air quality. It is ideal for residential and commercial use as it can capture 90% of airborne particles, such as lint, debris, pollen, dust, and pet dander. 

Best for the Money:
Aerostar Home Max Merv 13

Aerostar Home Max 16x25x1 MERV 13 Pleated Air Filter, Made in the USA, Captures Virus Particles, 6-Pack

PROS

  • Simple installation within minutes
  • Cost-effective solution for a healthier home environment
  • 100% of synthetic electrostatic media delivers high efficiency
  • Removes particles that could trigger asthma and allergy symptoms
  • Superior filtration efficiency removes unwanted particles such as mold spores, lint, dust mites, etc.

CONS

  • Some buyers have reported size issues

What Recent Buyers Report

It can be quite difficult to find a good-quality residential filter that provides good value for the money. However, recent buyers find this filter simply wonderful and everything that they were hoping for. Moreover, a buyer reported these filters did not come individually wrapped in plastic, which makes them environmentally-friendly.   

Why it Stands Out to Us

Excellent performance, coupled with a highly accessible price, makes this unit one of our favorites. It is able to remove microscopic particles from the air quite efficiently. With this unit, you are better able to take care of your family as it can capture unwanted allergens such as bacteria, pollen, and harmful virus carriers, thus protecting you from allergies. 

Moreover, it provides clean, healthy indoor air without putting much of a burden on users.  

Bottom Line 

In order to protect your HVAC system from overheating, it is best to use high-quality filters. With the Aerostar Home Max Mer 13, you can ensure improved indoor air quality for your loved ones. These filters keep your unit running smoothly while reducing the strain on the motor. As a result, your unit runs efficiently, requires very little maintenance, consumes less energy, and will be able to last a long time. 

Best Air Filter For Home Furnace:
SFP Filters Merv 8

SFP Filters - Merv 8 Air Filters 12 Pack (20' x 25' x 1') | Affordable Pleated Particulate Air Filters for Furnace, Air Conditioner & HVAC | Bulk Set for Home, Office, Industrial & Medical | USA Made

PROS

  • Helps reduce your energy bill 
  • Protects from allergies and viruses
  • Value saving packs help to save money per unit
  • Backed by 100% customer satisfaction guarantee
  • Highly effective in removing impurities from the air around you

CONS

  • None

What Recent Buyers Report

The SFP filters are very effective in providing clean air, and, for this reason, recent buyers are very satisfied with this product. They report that the air around them has become much cleaner and they love breathing in this fresh air. Buyers are so happy with this product that they plan on buying it again. 

Why it Stands Out to Us

These SFP filters help improve your home furnace's efficiency and save money on your energy bill. The best thing about these filters is that they provide fresher, cleaner air to your home while prolonging the life of your air filtration system. 

They are more effective than fiberglass filters and filter out the various bacteria, allergens, and airborne pathogens, thus ensuring long-term respiratory benefits for you and your family.

Another thing that we like about the SFP filters MERV 8 is that they are available in value saving packs, which makes it highly affordable to replace your home furnace filters and stock up for the months to come. 

Bottom Line 

If you are searching for an affordable way to clean the air of your home, warehouse, office, or commercial place, then SFP filters are the right option for you. With a MERV rating of 8, these filters are 20 times more effective than traditional fiberglass filters and are able to trap airborne particles like dust, pet dander, lint, allergens, and more. 

Best Washable Furnace Filter:
Carter Goods Merv 8

20X25X1 CARTER | MERV 8 | Lifetime HVAC & Furnace Air Filter | Washable Electrostatic | High Dust Holding Capacity

PROS

  • Backed by a lifetime warranty
  • Cleaning these filters is very simple and easy
  • High-quality construction with 94% dust-resistance
  • Strong and sturdy frame is ideal for all applications
  • Designed with antimicrobial material that inhibits bacteria and mold growth

CONS

  • Require regular cleaning to work efficiently

What Recent Buyers Report

Users are very happy with this filter as it is durable, washable, and provides the best value for money. They also find the customer service very helpful as the warranty request was dealt with promptly and efficiently. After using this product, buyers claim that they will never buy disposable filters anymore.

Why it Stands Out to Us

When it comes to quality filters, it is hard to find a product that can beat the price and quality of the Carter Goods MERV 8. It slides in the filter slot very easily and is also very easy to clean. Moreover, it does not hinder the airflow in any way. 

We are particularly impressed with the unique design of these filters. They are constructed with two layers of antimicrobial, self-charging electrostatic fibers that deliver a high capacity of dust retention. Its premium-quality gold anodized aluminum frame comes with an attractive and durable finish. Moreover, these filters come with a lifetime warranty that shows the manufacturer’s trust in this product.

Bottom Line 

The durable design and excellent performance of the Carter filters ensure users of a clean environment around their home. These filters are a definition of class and prestige, and with a MERV rating of 8, you can be assured of a clean air filtration system that is sure to last a lifetime.

Best Furnace Filter For Dust Control:
Winston Brands Vent Filters

Furnace AC Register Dust Control Vent Filters - Pack of 24 | Helps Trap Dirt, Dust, Smoke, Poolen Size Particles | Provides Fresh, Filtered Air | For Bathrooms, Bedrooms, Kitchen, Family Rooms

PROS

  • Can be cut to fit vents if needed
  • Reduces the need for yearly air duct cleaning
  • Can be inserted easily for a simple installation
  • Ideal for homes that get a lot of duct or smoke
  • Removes dust particles from your whole home

CONS

  • Some people find them very thin

What Recent Buyers Report

These vent filters have reduced the amount of dust in buyer’s homes by 50%, which is why they claim that they will buy these filters again. They are easy to install in most standard-sized vents. Buyers are happy with these filters as they trap dust well without reducing airflow.

Why it Stands Out to Us

The Winston Brands vent filters make it easier to maintain a clean home by serving as an extra line of defense against allergens and dust. Dust and other particles can bypass the main furnace filter by entering the ducts through cracks. They can also accumulate in the vents and further pollute the air you breathe. 

However, the Winston filters effectively trap smoke, dirt, dust, pet hair, and pollen-sized particles, thus providing you with fresh air. They also reduce the amount of cleaning and dusting that you have to do around the house, which we find highly convenient. In addition, these filters prevent dust from falling into ducts, thus eliminating the need to get your ducts cleaned every year and saving you money.     

Bottom Line

Dust is one of the main causes of allergies, and these filters provide effective protection against it. They clean up the air that you breathe, reduce the amount of dusting required around your home, and protect your family's health.    

Best Furnace Filter For Allergies:
Nordic Pure Merv 12

Nordic Pure 16x25x1 MERV 12 Pleated AC Furnace Air Filters 6 Pack

PROS

  • Attracts pollen, allergens, and other airborne contaminants
  • Ideal for people who live near industrial sites or in big cities
  • High-quality antimicrobial and hypoallergenic pleated filter material
  • Provides exceptional air filtration in both commercial and residential environments
  • Designed with electrostatically-charged material that attracts all unwanted particles

CONS

  • Quality could be improved

What Recent Buyers Report

These filters have worked quite well for recent buyers. They have not had any issues with their installation or performance. They help remove unwanted particles as well as pet dander, thus saving you and your family from allergies and asthma attacks.

Why it Stands Out to Us

The Nordic Pure MERV 12 are constructed with electrostatically-charged synthetic materials that trap most airborne particulars in your office or home. This pleated furnace filter removes pollen, mold spores, pet dander, smog, dust mites, household dust, lint, and germs from sneezing and coughing. Moreover, the synthetic filter media stops mold or bacteria from growing, thus providing you with a healthy living space. 

Another thing that we like about these units is that they are environment-friendly as they are framed with recycled beverage board paper. These filters not only improve the air quality but they also increase the efficiency of your HVAC unit.  

Bottom Line

These high-performing filters are more efficient than other filters, including poly disposable filters, non-electrostatic fiberglass filters, and washable filters. In addition, they keep your furnace working optimally, thus helping you save money on costly maintenance and utilities. 

Types of Furnace Filters

Furnace filters are of different kinds. While their main purpose is the same, there are significant differences between them. Some different types of furnace filters include:

Disposable Fiberglass

The most common filters used for residential applications are those made out of disposable fiberglass. They feature a glass fiber that gets woven tighter as the layers increase. The tighter the woven fingers, the better the MPR and MERV ratings. 

Pleated Allergen Filters

Such filters feature a paper fiber filter material that is pleated to increase the surface area. As the pleats in the filter increase, so does the surface area. As a result, there’s more surface area for air to flow through and capture particles. 

Moreover, the pleats allow for more filter material along with tighter filtering. Therefore, they can capture airborne particles that are as small as up to three microns. Pleated allergen filters are available in different residential sizes ranging from 12 to 60 inches.

Activated Carbon Filters  

Also known as charcoal filters, activated carbon filters are anti-allergen. They feature paper fibers or pleats coated with carbon that captures odors and pollutants to minimize unpleasant smells in the home. 

Aerostar Home Max Merv 13

With carbon or charcoal on the filter material, the airflow is not restricted. Plus, apart from in-home allergens, such filters can capture cigarette smoke along with particles that can irritate the nasal passageway and cause sneezing and coughing. 

HEPA Filters 

HEPA filters are basically filters made of mesh material, paper, or fiberglass and are rated to capture particles that measure as small as three microns, such as pollen, mold, pet dander, and mildew. You can easily find a suitable size for most commercial and residential units; however, the larger sizes can be relatively more expensive.  

Comparison Overview 

Buying a furnace filter is not as simple as it seems. There are a plethora of variants to choose from, with each serving a different purpose, which makes choosing one difficult. To help make things clearer, here is a comparison between the different kinds. Go through the following comparisons to determine which filter would be the ideal pick for you. 

Washable Furnace Filters vs. Disposable

A disposable filter is one of the most common air filters. After a few months of use, you will have to throw it away and put a new one in your furnace. On the contrary, washable or electrostatic filters are more commonly known as permanent filters.

Washable filters feature an aluminum frame with woven static-prone electrostatic filters that attract airborne particles. Once the filter accumulates dirt and dust after a few months, it is taken out and washed to clear away the debris.

Moreover, disposable filters are effective at trapping smaller particles, while washable ones can only filter out large particles like dust. The latter does not filter out particles like smoke, viruses, bacteria, and dander.

 4 Inch vs. 1 Inch Furnace Filters

Generally, four-inch filters have a higher MERV rating as compared to one-inch filters. You will usually find one-inch filters with MERV rating ranging from one to 13 and four-inch filters with a MERV rating between eight and 16. Buying a four-inch filter means that you would get a filter with a minimum MERV rating of 8, which would be able to get rid of contaminants as small as three microns. 

In addition, you will find yourself replacing one-inch filters more frequently than you would a four-inch one. This is because the latter has larger pleats, which means it has a larger surface area for capturing particles. As a result, it lasts up to five times longer than one-inch filters.

HVAC technicians suggest changing one-inch filters every month while you won’t need to change four-inch filters for three to six months. In fact, some can even last as long as one year. 

1 Inch vs. 2 Inch Furnace Filter

A two-inch filter can be used in a vent if it is deep enough, and when compared to a one-inch filter, it will last longer because it has more media. 

In addition, a two-inch filter is better at maintaining the system. It has a static pressure of just 0.158” WC and can keep the system from struggling. 

Conversely, a one-inch filter can be damaging for the system, especially if it is not changed monthly. 

Furnace Filter Ratings MERV vs. MPR

Both MERV and MPR are metrics for measuring a filter’s efficiency. However, the latter measures microparticles that are between 0.3 and one microns in size. Meanwhile, the former measures microparticles too, but only in filters with a MERV rating of 11 or higher. 

MERV is an industry standard for filter ratings and ranges from 1-16; the higher the rating, the better the filtration. On the other hand, MPR is only used for Filtrete HVAC filters by 3M and ranges from as low as 100 (equal to MERV rating one) to as high as 2800 (equal to MERV rating 14). 

Furnace Filter vs. Air Filter

Many people often talk about furnace and air filters as they are different; however, that’s not true. Whether your house has a central air conditioning and heating system or a separate furnace and AC unit, both share the air-handler, which is where the filter resides. Therefore, both use the same filter; there’s no difference between the two. 

Is a Furnace Filter And an Air Filter the Same Thing?

Furnace filters, air filters, whole home filters, heater filters, HVAC filters, and air handler filters all refer to the same thing. Your air conditioner, furnace, or HVAC unit all refer to the same filter, regardless of what you call it.  

How to Clean a Furnace Filter

To make sure that your furnace works as efficiently as possible, you must clean it thoroughly. Here is how you can do so:

  1. Firstly, turn off the power supply to the furnace.
     
  2. Locate the furnace filter. This might be a bit tricky since different furnaces have different locations for the filter. It might be placed behind a door, or you might even find it behind a panel. You can refer to your owner’s manual to know the location.

  3. Once you find the dirty filter, it is time to remove it. Simply slide the filter in and out of the housing.

  4. Now is the time to wash it. Make sure to hose it until you see clear water coming out from the other side. Also, note that if the filter features a cardboard frame, you shouldn’t wash it. Instead, you should replace it. 

  5. Let the filter dry.

  6. Once it is completely dry, put it back into its place and turn on the furnace.

Cleaning the filter is as simple as that. Here’s a video that shows the entire process described above. 

How To Change a Furnace Filter

Once your furnace filter is so dirty that it becomes ineffective, it is time to change it and put in a new one. To do so, here’s what you need to do:

  1. Find the filter. Each furnace has a different location for the filter, and you’ll have to look around your unit for a bit to find it.

  2. Once you find it, it is time to start the replacement process. For this, first, turn off the furnace. 

  3. Now, take out the old filter. 

  4. Next, take a new filter and write the installation date on it using a permanent marker.

  5. Slide it in and put the cover back on. Finally, turn on the furnace again. 

Furnace Filter Replacement Tips

Replacing a furnace isn’t hard; it just involves a few basic steps. However, by keeping in mind the following tips, you can make the task even easier:

  1. Remember to replace your furnace filter regularly. If you don’t do so for a long time, your unit will start posing problems. For instance, it will overheat and stop heating, or the blower motor might burn out. 

  2. The furnace filter is always located on the furnace’s return side. If you can’t differentiate between the return and supply side, then simply turn on your furnace for five to ten minutes. Then, feel the ductwork; the cold side will be the return side, and you’ll find your filter somewhere on or near it.

  3. If you have an attic unit, then the filter’s location will change. They will be in your ceiling behind the return grills instead of before the furnace. 

  4. If there is a big gap between the filter and the furnace ductwork, it is best to cover it with a piece of wood or tape to protect the filter.  

  5. If you find yourself struggling when trying to take out the filter from its place, you can just take off the furnace doors and push on the filter from the inside to dislodge it from its place. 

  6. To make replacement easier and hassle-free, you can write the size of your filter as well as the direction of the airflow on the return side. Writing the filter size will make it easy to buy one for a replacement since you won’t have to take out your old filter again and again to check the size. 

  7. Before installing a new filter, use a piece of tape and make a tab on top so that it is easy to just pull it out when you have to replace it again.

You now know everything there is to make filter replacement easy. If you still have any doubts, you can check out this video:

Conclusion 

Despite being a small part of your furnace, it is now clear that having the best furnace filter is essential. A low-quality one will not only make the unit work harder, but it will also not filter out particles completely. If you’re unsure of which filter to go for, you can have a look at our list and choose one that meets your needs. 

People Also Ask

Given the different kinds of filters available, along with variation in features such as MERV rating and filter media, you are bound to have some questions regarding furnace filters that might still be unanswered. Here are a few questions that people commonly ask that you should check out before finalizing a purchase. 

Where Is My Furnace Filter Located?

The furnace filter will be present anywhere near the fan. It can be found inside the duct opening, behind panels, or behind equipment to keep it shielded. You’ll often find it located somewhere in the duct system, near the air handler. To find the filter, it is best to start looking for it from the air handler and go back from that point until you come across it. In some cases, you might find it at the return air grille opening or behind the return air grille. 

What Size Furnace Filter Do I Need?

To measure the furnace filter, you need to measure three dimensions: width, length, and thickness. The dimensions are usually measured in inches. Getting the right size is important as the wrong filter won’t fit or stay in place once you install it. The size of the furnace filter you need will be mentioned in the owner's manual that comes with your unit. 

Can I Clean My Air Filter Instead of Replacing it?

This depends on the kind of air filter you have. If you have a disposable air filter, then you have no choice but to replace it. This is because trying to clean it could lead to issues like mold and inefficiency. Therefore, you must replace a disposable filter after a month or so. 

However, if you have a washable filter, then you can clean it instead of replacing it. Keep in mind, though, that washable filters only work the best for three to six months; after that, they will have to be replaced, too. 

How Good Are Washable Furnace Filters?

Washable filters aren’t really known to be effective at air purification. Their MERV rating lies between one and four, and they are only able to capture larger contaminants, such as pollen, carpet fibers, dust mites, and dust. 

How Often To Change Furnace Filter?

It is important to change furnace filters regularly. Usually, it is best to change them every one to three months. A few thicker filters, like four-inch ones, can last even up to 12 months, but this depends on where they are used and what they filter. For instance, if you live in an area with a lot of airborne contaminants and dust, then you’ll have to change the filters more frequently. 

Why Does My Furnace Filter Get Dirty So Fast?

There are many reasons why your furnace filter gets dirty so fast. One of the biggest reasons could be the greater amount of dust in your house. This is especially true if you have carpets in your house since they trap a lot of dust. A fan set on “on” instead of “auto” can also be responsible for the filter getting dirty so quickly. This means that the filter will be continuously working, thus attracting more particles to it.

In addition, your filter could get dirty quicker if it has a high MERV rating. Such filters filter a lot of particles in the air, so they are bound to get dirty quickly. Other reasons include pet hair and leaky ductwork. 

Why Is My Furnace Filter Black?

Incomplete combustion in your furnace produces carbon monoxide. While carbon monoxide itself is colorless, it can turn your furnace filters black. 

What Happens If You Don't Change Your Furnace Filter?

If you keep using the same furnace filter, eventually, it will become ineffective at trapping particles, leading to a number of problems. These include poor heating performance and higher energy costs. In fact, your furnace might break down and stop working even before its expected lifespan. You might also notice reduced heating in some parts of the house. 

Which Way To Install Furnace Filter?

The right way to install the filter depends on the furnace you have. Generally, you will see arrows clearly marked on the filter to indicate the right direction. Make sure to insert the filter such that the arrows point to the unit’s inside.  

What Happens if Furnace Filter is Backwards?

If you install a furnace filter backward, then it will restrict the airflow. The fibers in the filter can also not do their job properly, so your furnace has to work harder to maintain the same airflow. This will increase your energy costs. In addition, with the filter placed backward, dust and other particles will start building upon it irregularly, making your unit work harder to draw in air.  

Can A Furnace Have Two Filters?

Most furnaces feature a V-shaped filter system that can take two filters. However, this isn’t necessary; your model can have one filter as well. 

Are Electrostatic Furnace Filters Better?

Electrostatic furnace filters are better in some aspects. For instance, they are the most cost-effective, and they usually have a higher MERV rating of five or six. They are also better at improving air quality. However, they are unable to filter out larger dust particles and are not ideal for people with allergies. 

Are More Expensive Furnace Filters Worth It?

As a general rule of thumb, more expensive furnace filters are definitely worth it because they can capture smaller particles compared to cheaper units. In addition, they need fewer repairs. 

What Is the MERV Rating On Furnace Filters?

MERV (Minimum Efficiency Reporting Value) is a rating system designed by ASHRAE (American Society of Heating, Refrigeration, and Air Conditioning Engineers). It is basically an indication of the size of particles that the filter can capture. 

My name is Bob Wells and I am a retired HVAC tech from Washington state. I am currently retired and no longer do much with HVAC, however, I feel like I have a lot of knowledge in the subject and I wanted to create a website where I could talk about what I've learned and help upcoming HVAC techs. Find more info about me and HVAC Training 101.