Discover the Main Types of Furnace Filter Sizes for Your Home

Are you tired of constantly changing your furnace filters without knowing which size is the right one? Look no further! In this article, we will be discussing the main types of furnace filter sizes to help you find the perfect fit for your home.

Choosing the right size filter not only helps improve the air quality in your home, but it can also improve the efficiency of your furnace. With so many different sizes out there, it can be overwhelming to know where to start. Luckily, we've got you covered!

From common sizes to oddball dimensions, we'll break down the differences between each filter so you can find the perfect fit for your furnace. Say goodbye to guessing games and hello to fresh air in your home with our guide to furnace filter sizes!

1. Standard Filter Sizes

When it comes to furnace filters, standard sizes are the most common. These sizes are readily available at most hardware stores and are an excellent starting point for homeowners who may not know what size filter their furnace requires. The most common standard filter sizes are 16x25 inches, 20x25 inches, and 16x20 inches. However, other popular sizes include 14x20 inches, 14x25 inches, and 20x20 inches. It is essential to note that not all furnaces require standard filter sizes, so it is always essential to check the HVAC system's specifications before making a purchase. One pro tip is to measure existing filters before shopping for replacements. This way, you will have a precise measurement of the filters that you need, which will help avoid any guesswork. Replacement filters can come in various levels of MERV ratings, and this will also need to be considered when making a purchase. Overall, standard filter sizes are an excellent starting point for homeowners looking for furnace filters. They are easy to find and usually are more affordable than custom filter sizes. However, it is always best to check the HVAC system's specifications to ensure that you are purchasing the correct size filter for your furnace.

2. Non-Standard Filter Sizes

Not all homes have standard-sized furnace filters. Some homes may require non-standard filter sizes due to the size, shape, or layout of the HVAC system. If you have a non-standard size for your furnace filter, don't worry. There are many options available to accommodate your needs. For instance, you can have custom-made filters made to fit your exact specifications. You can also purchase filters that can be trimmed to fit your specific measurements. Trim-to-fit filters usually come in larger sizes that you can easily adjust to fit your furnace ducts, making them a cost-effective solution. Alternatively, you can use filter adapters. These are frames that allow you to use standard-sized filters in non-standard ductwork. Filter adapters come in various sizes to suit different HVAC systems. Whatever your non-standard filter size is, remember that it's essential to change your furnace filters regularly to maintain air quality and reduce allergens in your home. Consult with a certified HVAC technician to ensure you get the best filter size and type for your system. In conclusion, whether you have a standard or non-standard filter size, there are many options available in the market. Choose the best fit for your HVAC system to maintain clean air quality and ensure the efficient functioning of your furnace.

Understanding MERV Ratings for Your Furnace Filter

When it comes to choosing a furnace filter, one important factor to consider is the Minimum Efficiency Reporting Value (MERV) rating. MERV ratings range from 1 to 20 and indicate the filter's effectiveness at capturing airborne particles like dust, pollen, and pet dander.

A higher MERV rating means the filter will trap more particles, but it can also reduce airflow and strain your HVAC system. It's essential to balance your desired level of filtration with your system's capabilities.

For most households, a filter with a MERV rating between 8 and 11 is sufficient. These filters capture a wide range of particles without overtaxing your HVAC system. However, if you or a family member has allergies or asthma, a higher MERV rating, such as 13 or above, may be necessary to reduce allergens and improve air quality.

Keep in mind that a filter's MERV rating is not the only factor in determining its effectiveness. The type of filter material and thickness can also affect its performance. It's essential to choose a filter that is compatible with your HVAC system and fits properly to maximize its efficiency.

Regularly replacing your furnace filter is crucial regardless of its MERV rating. A dirty filter can reduce airflow and strain your system, leading to higher utility bills, and the potential for expensive repairs. Experts recommend replacing your filter every three months or more often if you have pets or allergies.

With a basic understanding of MERV ratings, you can make an informed decision when choosing a furnace filter that is right for your home and improve the air quality for you and your family.

Pleated Filters: A Popular Option for Improved Air Quality

If you're looking to improve your home's indoor air quality, consider switching to a pleated furnace filter. These filters have become increasingly popular in recent years due to their highly effective filtration system and ease of use.

Pleated filters are made up of several layers of folded material, which creates a larger surface area for capturing airborne particles such as dust, pollen, and pet dander. This increased surface area results in improved air quality as more particles are trapped before they can circulate around your home.

One of the benefits of pleated filters is their longevity. They typically last longer than other types of filters, meaning you won't need to replace them as often. Additionally, pleated filters tend to have a higher MERV rating (minimum efficiency reporting value), which measures their effectiveness in trapping particles. The higher the MERV rating, the more efficient the filter.

When it's time to replace your pleated filter, it's important to choose the correct size. Like other types of filters, pleated filters come in various sizes depending on the dimensions of your furnace. Make sure to check your furnace manual or consult with a professional to determine the right size filter for your system.

Overall, pleated filters are a great investment for homeowners looking to improve their indoor air quality. They are efficient, long-lasting, and readily available in a variety of sizes to fit your specific furnace system.

5. Electrostatic Filters

If you're looking for a high-efficiency filter option, an electrostatic filter might be the perfect choice for you. An electrostatic filter uses a science called electrostatic attraction to capture tiny particles that other filters may miss.

These filters are typically made of synthetic polyester material and come in a few different variations. Some electrostatic filters are washable and reusable, which can save money in the long run. Others are disposable, and some even come with a carbon layer to help remove odors from the air.

When selecting an electrostatic filter, it's important to pay attention to the MERV rating, as these filters can range from 1 to 16 in efficiency. A higher MERV rating means finer filtration, but it can also mean more strain on your HVAC system. Check with your manufacturer or HVAC technician to ensure that your system is compatible with the MERV rating you choose.

Overall, electrostatic filters are an effective option for removing a variety of pollutants from your indoor air, and they come in a range of sizes to fit any furnace.

Conclusion: Choose the Right Furnace Filter Size for Better Indoor Air Quality

As you can see, there is no one-size-fits-all solution when it comes to furnace filter sizes. You need to choose the right size based on your HVAC system specifications and your indoor air quality needs.

When you opt for the right furnace filter size for your home, you can ensure better air quality, improved energy efficiency, and longer equipment lifespan. So, don't overlook the importance of choosing the right filter size, and consult with a professional HVAC technician for expert guidance.

With this information, you can now make an informed decision and select the best furnace filter size for your home. If you have any questions related to furnace filters or your HVAC system, feel free to contact us, and we'll be happy to assist you.

Frequently Asked Question

It's important to know the size and type of furnace filter you need before replacing it. This is because different furnaces require different sizes of filters. Your brand of furnace may need an electrostatic or media filter of a particular size - so make sure to check your old filter for these details.


Replacing your filter regularly can save you money in the long run. It helps your HVAC system become more efficient, and also keeps the air quality high. So, what are the most common furnace filter sizes?


The most popular furnace filters come in the following dimensions: 10x20, 14x20, 16x24, 18x30, 12x12, 14x24, 16x25, 20x20, 12x20, 14x25, 18x18, 20x24, 12x24, 14x30, 18x20, 20x25, 12x30, 15x20, 18x24, 20x30, 12x36, 16x20, 18x25, 24x24 and 25x25. You can use your existing filter as a reference guide to find the perfect size for your furnace. The filter dimensions should be printed on its frame as length x width x height.


In conclusion, it's important to know your furnace filter size before you replace it. Doing so will improve your HVAC system's efficiency and save you money in the long run. Plus, a clean filter is key to keeping your air quality high.

When it comes to furnace filters, exact size matters. If you get a filter that is too small or too big, air will flow around it instead of through it, meaning not all of the air will be filtered. That's why it's essential to use the right size filter for your HVAC unit.


Here's what you need to know: the size of the air filter is typically listed in the big, bold font on the packaging, which is known as the nominal size. This is a rounded-up whole-number version of the actual size, which is written in the fine print on the filter's frame. That's usually 0.25'-0.5' smaller than the nominal size, and the actual measurements of the filter may vary slightly depending on the brand.


In some cases, less common sizes come true to size, meaning the nominal size is the same as the actual size. When that's the case, it's usually noted with “actual size” in parentheses on the filter's frame.


So, the verdict is in: the answer to the question 'Do furnace filters have to be exact size?' is a resounding yes! Be sure to get the right size air filter for your system to ensure it runs smoothly and that you reap all the benefits your filter has to offer.

Are you looking for the best furnace filter? Look no further! Our team of experts at This Old House Reviews have researched the top five furnace filters on Amazon to help you find the perfect one for your HVAC system. Plus, these products are available at local home centers or online retailers like Amazon.


A great furnace filter can make all the difference. It will keep your HVAC system running smoothly, potentially leading to lower electricity bills and better air quality. That's why we've taken the time to compile a list of the best furnace filters for you.


At the top of our list is the Filtrete furnace air filter. It promises to last up to three months and outperform filters made with fiberglass. Plus, it can capture 64% of airborne particles like pet dander and pollen. This filter also comes with instructions for easy installation on HVAC systems that require filters 20 by 25 by 1 inches in size.


Customers love this furnace filter. They find it easy to install, sturdy, and a great value. However, some customers have faced difficulties with Filtrete’s app.


When choosing a furnace filter, make sure to take into account its size, filtration level, and material. That way, you can get the best filter for your specific needs.

Changing or replacing your furnace filter is one of the best ways to maintain a healthy, efficient HVAC system. But you need to make sure that you're using the right filter for your system. Here's a step-by-step guide to help you pick the perfect one!


First, measure the dimensions of your existing filter. This will tell you the length, width, and depth you need. The easiest way to do this is to look at the existing filter and buy the same size.


Next, you need to choose the right MERV rating. The MERV scale ranges from 1-20 and measures the filter's effectiveness at catching particles in the air. The higher the value, the more effective the filter is at trapping particles, but it also means less airflow.


Now it's time to decide on the type of filter. There are many options available, so take some time to research the best type for your system.


Once you have everything you need, it's time to install the filter in your furnace/air handler slot. Remove the old filter to make room for the new one.


Finally, make sure to replace your filter regularly. If it clogs up with dust and particulate, it can reduce airflow and become ineffective.

Furnace air filters are essential for your heating system. You should replace your filter at least once every three months. So, how do you select the best furnace filter for your needs? Let us help you out!


Generally, furnace filters are made up of a cardboard frame, fiberglass filter, and metal mesh. These materials work together to strengthen the filter and protect your HVAC components from dust and debris. Plus, they also help improve the air quality in your home. Without a filter, your HVAC system could become dirty and its performance would suffer.


As air passes through the furnace filter, it traps and catches any contaminants. If you don't replace or clean your filter regularly, it can obstruct airflow and cause damage to your HVAC system. In most cases, you should change your furnace filters every three months. However, you may want to replace them more or less often depending on the situation.