How to Choose the Perfect Furnace Filter Sizes for Your Home

Struggling to find the right furnace filter size for your home? Look no further because we've got you covered. Choosing the right furnace filter is crucial when it comes to maintaining the air quality in your home. Poor indoor air quality can lead to health problems, so it's important to make sure you're using the right filter size for your furnace.

Not sure where to start? In this article, we'll cover everything you need to know about choosing the perfect furnace filter size for your home. We'll break down the different types of filters available and explain how to measure your existing filter to ensure a perfect fit. By the end of this article, you'll be a pro at selecting the right furnace filter for your home.

Don't let the process of choosing a furnace filter size stress you out. With our tips and advice, you'll be able to find the perfect filter in no time. Get ready to breathe clean and healthy air in your home with our helpful guide.

Understanding Furnace Filter Ratings

Furnace filters are rated based on their ability to capture dust, air pollutants, and allergens. The higher the rating, the smaller the particles the filter can capture.

MERV (Minimum Efficiency Reporting Value) rating is the most common rating system used for furnace filters. The range for MERV ratings is from 1 to 20. The higher the MERV rating, the more efficient the filter is. However, a high MERV rating can also restrict airflow, which can cause problems for your furnace.

A MERV rating of 1 to 4 is considered low and provides minimal filtration. These types of filters are designed to protect your furnace and do not capture small particles that can affect indoor air quality.

A MERV rating of 5 to 8 is considered medium and can capture some common pollutants like pollen, pet dander, and mold spores.

A MERV rating of 9 to 12 is considered high and can capture smaller particles, including some viruses and bacteria.

A MERV rating of 13 to 16 is considered very high and can capture even smaller particles, such as smoke and some types of bacteria.

If you or someone in your household has a respiratory condition or allergies, a higher MERV rating filter may be beneficial. However, it is important to consult with an HVAC professional to ensure that the filter does not restrict airflow and cause problems for your furnace.

Overall, understanding furnace filter ratings can help you choose the right filter for your home, which can improve indoor air quality and protect your furnace. Consult with an HVAC professional if you have any concerns about choosing the right furnace filter for your specific needs.

Measuring Your Existing Furnace Filter

Before you choose a new furnace filter, it's important to measure your current one properly. This will ensure that you choose the right size and avoid any problems in installation. Here's how to measure your existing furnace filter:

Step 1: Turn off your furnace.

Step 2: Locate your existing filter. It's typically located in the air handler or the return air duct.

Step 3: Carefully remove the filter from its slot.

Step 4: Check the filter's dimensions. You'll typically find the dimensions printed on the filter's edge, but if not, use a tape measure to measure the length, width, and depth of the filter.

Step 5: Note down the dimensions, and double-check them to ensure accuracy.

Knowing the dimensions of your existing furnace filter will make it easier to choose the perfect filter for your needs. Remember to replace your filter on a regular basis for optimal air quality and furnace efficiency.

Choosing the Right Material for Your Furnace Filter

Now that you know how to determine the right size for your furnace filter, it's important to consider the material it's made of. There are several options available, each with their own strengths and weaknesses.

The most common types of furnace filter materials are fiberglass, pleated, electrostatic and HEPA. Fiberglass filters are the most affordable but only offer basic filtration, while pleated filters offer better filtration and longer lifespan. Electrostatic filters use static electricity to trap particles and can be washed and reused, and HEPA filters offer the highest level of filtration but can be costly.

Consider your family's needs and budget when choosing a furnace filter material. If someone in your household suffers from allergies or respiratory issues, investing in a high-quality filter like a HEPA could make a big difference. If you have pets, a washable electrostatic filter could save you money in the long run.

It's also important to note that higher quality filters can lead to better indoor air quality but may also put more strain on your hvac system. Be sure to check your furnace's specifications and recommended filter type before making your final decision.

Ultimately, the right furnace filter material for your home will depend on your specific needs and budget. Don't hesitate to do some research or ask a professional for advice to ensure you're making the best choice for your household.

Determining the Right MERV Rating for Your Furnace Filter

Once you have determined the right size of your furnace filter, the next thing to consider is the MERV rating. MERV stands for Minimum Efficiency Reporting Value, which measures a filter's effectiveness in removing airborne particles. A higher MERV rating means better filtration, but it also means your HVAC system has to work harder to circulate the air.

The MERV rating system ranges from 1 to 20. A MERV rating of 1-4 is the minimum and only captures large particles like pollen and dust mites. A MERV rating of 5-8 captures particles like pet dander and mold spores. A MERV rating of 9-12 captures finer particles like smoke and bacteria. Finally, a rating above 13 captures very fine particles like viruses and tobacco smoke.

While a higher MERV rating might seem better, it's important to consider your HVAC system's capability before choosing a filter. High-efficiency filters with a MERV rating of 13-16 can restrict airflow, causing strain on your HVAC system and potentially reducing its lifespan. So, it's best to stick with filters within the MERV 7-13 range.

It's also important to note that a higher MERV rating does not necessarily mean better air quality. Filters with a MERV rating above 13, for example, are designed for hospitals and other specialized medical facilities where the air quality needs to be strictly controlled.

In conclusion, when choosing a filter, it's important to consider both the size and the MERV rating. You want to choose a filter that is suitable for your HVAC system and can capture the particles that matter most to you.

Choosing the Best Furnace Filter Size for Your Home's Needs

When it comes to selecting the right furnace filter size for your home, there are a few factors that you should consider. Here are some tips to help you choose the best filter size for your home's needs.

First, check your furnace's current filter size. This should be listed on the filter itself or in your furnace's manual. It's essential to ensure that you choose the correct size filter to ensure it fits correctly and functions effectively.

The second factor to consider is the MERV rating of the filter. MERV stands for Minimum Efficiency Reporting Value and is a standard rating system for filters' effectiveness. A higher MERV rating means that the filter can capture more tiny particles, such as pollen, pet dander, and dust, from the air. However, a higher MERV rating also means that the filter can restrict airflow, leading to reduced efficiency and potentially increased energy bills.

The final factor to consider is the type of filter you choose. There are many options available, including fiberglass, pleated, and electrostatic filters. Each filter type has its pros and cons, such as how long they last, how effective they are, and their cost. It's crucial to weigh up these factors before making your selection.

In conclusion, choosing the perfect filter size for your furnace is essential to ensure it functions efficiently and provides high-quality air for your home. Remember to check your furnace's current filter size, consider the MERV rating, and choose the best filter type to meet your needs. Don't hesitate to seek advice from a professional if you're unsure about which filter to choose.


Choosing the perfect furnace filter sizes for your home is an important decision that requires careful consideration. Always consult with a professional to ensure you are selecting the right filter size for your furnace. Remember to prioritize the MERV rating and buy high-quality filters for optimal indoor air quality. By following the steps outlined in this article, you can ensure that your furnace is running efficiently and your family is breathing clean air.

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.