The Surprising Truth About Furnace Filter Sizes: The Most Cost-Effective Way To Buy Them

Are you tired of spending extra money on furnace filters that don't fit your system properly? Do you want to save money without sacrificing air quality? If so, keep reading!

It turns out that furnace filter size is not a one-size-fits-all solution. In fact, using the wrong filter size can have significant consequences on the efficiency and lifespan of your furnace.

But don't worry, we've got you covered. In this article, we'll share the most cost-effective way to buy furnace filters that are both the right size for your system and high-quality enough to keep your air clean and healthy.

1. How the Right Furnace Filter Size Can Save You Money

Choosing the right furnace filter size can have a significant impact on your home's heating and cooling efficiency. A filter that's too small or too large can cause airflow problems and reduce the lifespan of your furnace. However, selecting the right size can also save you money on energy bills and filter replacements.

When a filter is too small, it can allow dirt, dust, and other contaminants to pass through and clog up the system's heating components. This can force your furnace to work harder and reduce its lifespan. Similarly, when a filter is too large, it can reduce airflow and put a strain on your furnace, leading to increased energy consumption.

By selecting the correct size filter, you can ensure optimal airflow and reduce strain on your furnace, leading to lower energy bills and fewer filter replacements. Additionally, choosing a more efficient filter can further improve your home's energy efficiency and reduce costs over time.

When shopping for filters, be sure to consult the manufacturer's specifications to determine the correct size for your furnace. Additionally, consider investing in higher-quality filters with a higher MERV rating. While these may be more expensive upfront, they can provide better filtration and last longer, ultimately saving you money in the long-run.

Don't underestimate the importance of choosing the right furnace filter size for your home. By selecting the correct size and investing in a more efficient filter, you can improve your heating and cooling efficiency and save money on energy bills and filter replacements.

Understanding Furnace Filter Sizes

When it comes to replacing your furnace filter, understanding the size is crucial. Filters don't come in a one-size-fits-all option, and choosing the wrong size can lead to problems.

The size of your furnace filter depends on the make and model of your HVAC system. Before purchasing a filter, you need to know the correct size to avoid wasting time and money on filters that don't fit correctly.

You can find the size of your existing furnace filter by checking the dimensions printed on the side of the filter. The size usually appears in a format like 16x20x1. The first two digits are the length, the second two are the width, and the third digit represents the thickness of the filter.

If you can't find the size of your filter or are unsure about what size you need, consult your manufacturer's manual or contact your HVAC technician for assistance. It's better to take the time to figure out the correct size before making a purchase, as using the wrong size filter can cause air leaks and reduce the efficiency of your system.

Understanding furnace filter sizes can save you time, money, and keep your HVAC system working effectively. Always make sure to replace your filter regularly and use the correct size for optimal efficiency.

The Importance of Using the Right Size Filter

When it comes to changing furnace filters, many homeowners just grab whatever size they think will fit their system, without realizing the importance of using the right size filter. But using the wrong filter size can have serious consequences for both your wallet and your health.

First and foremost, using the wrong size filter can lead to decreased efficiency and increased energy costs. Your furnace is designed to work with a specific filter size, and using a filter that is too small or too large can cause airflow problems, reduce performance, and ultimately increase your energy bills.

But even more concerning is the impact that using the wrong size filter can have on your indoor air quality. If the filter doesn't fit properly, it can allow for unfiltered air to pass through, potentially causing health issues for you and your family. In addition, a filter that is too small may become clogged more quickly, trapping harmful particles like pollen, dander, and dust inside your home.

So, what's the solution? The most cost-effective way to buy furnace filters is to purchase them in bulk, but only if you're sure you're buying the correct size for your system. Don't hesitate to consult your furnace manual or contact a licensed HVAC professional if you're unsure about which filter size you need. It's better to be safe than sorry when it comes to the health of your home's air quality, and using the right size filter is an easy way to ensure that you're doing everything you can to maintain a safe and comfortable environment.

How to Determine the Correct Filter Size for Your Furnace

Getting the right size for your furnace filter is crucial for efficient filtering and saving on energy costs. Follow these steps to determine the correct filter size for your furnace:

1. Check the Current Filter Size: The size of the existing filter is typically printed on the side of the frame or on the filter itself. Make a note of the dimensions before going to purchase a new one.

2. Measure the Filter Slot: If your current filter is missing or you're not sure the size, you can measure the slot where the filter is placed. Measure the length, width, and depth in inches to determine the size of the filter needed.

3. Check the Furnace Manual: If you don't have access to the current filter or the filter slot measurements, consult the furnace manual to find the appropriate filter size recommendation.

4. Seek Professional Help: In some cases, determining the correct filter size can be complicated or require specialized knowledge. You might want to seek advice from an HVAC technician who can help you get the correct measurements and recommendations for the best filter size for your furnace.

By following these steps, you can ensure that the filter you buy is the correct size for your furnace, and you can optimize your furnace’s energy efficiency while reducing your home's heating and cooling costs.

Factors to Consider When Choosing Furnace Filters

Choosing the right furnace filter for your HVAC system can be overwhelming due to the variety of options available in the market. Here are some factors to keep in mind when selecting the best furnace filter for your needs:

1. Filter Size

The size of the filter you choose matters a lot. Ensure that you buy the exact size recommended by the manufacturer of your HVAC system. Using the wrong size of filter can affect the performance of your furnace and increase your energy bills.

2. MERV Ratings

MERV stands for Minimum Efficiency Reporting Value and is a measure of a filter's efficiency in trapping airborne particles. Filters with higher MERV ratings can trap more pollutants, but they can also restrict airflow, impacting the performance of your HVAC system. Choose a filter with a MERV rating that suits your needs and does not compromise the efficiency of your furnace.

3. Frequency of Replacement

You'll need to change your furnace filter periodically. Knowing how often your filter needs to be replaced can help you plan and budget accordingly. Standard filters can last up to three months, while high-efficiency filters can last up to a year. However, if you have pets or allergies, you may need to change your filters more frequently.

4. Type of Filter

There are several types of filters available, including fiberglass, pleated, washable, and electrostatic filters. Each type has its specific advantages and disadvantages. Consider your specific needs and the condition of your home before choosing the best filter type for you.

5. Cost

Furnace filters come in different prices, depending on the brand, type, size, and efficiency level. While expensive filters may be more efficient in trapping airborne particles, they may not necessarily be the best fit for your budget. Choose the filter that offers you the best balance between cost and efficiency.

Considering these factors when choosing furnace filters can help you make an informed decision that will not only improve your indoor air quality but also help you save on energy bills.

Cost-Effective Ways to Buy the Right Size Furnace Filters

If you're like most homeowners, you're probably looking for ways to save money on your heating and cooling bills. One way to do that is to make sure you're using the right size furnace filter. Using the wrong size filter can cause your furnace to work harder than it needs to, which can lead to higher energy bills and more frequent repairs. So, how do you find the right size filter without breaking the bank? Here are a few cost-effective tips:

1. Know Your Furnace's Filter Size

The first step in buying the right size filter is to know your furnace's filter size. This information can usually be found in your furnace's manual or on the existing filter itself. Make note of the filter's dimensions, including its width, height, and depth, and keep them handy when shopping for a replacement.

2. Buy in Bulk

Buying furnace filters in bulk can save you money in the long run. Many retailers offer discounts for buying multiple filters at once, and you'll save on shipping costs if you buy in bulk as well. Plus, you won't have to worry about running out of filters and having to pay full price for a single filter at the last minute.

3. Look for Sales and Discounts

Another way to save money on furnace filters is to look for sales and discounts. Many retailers offer promotions at certain times of the year, such as before the start of winter, so keep an eye out for these deals. You can also check online marketplaces for deals on bulk purchases of filters.

4. Consider Switching to a Reusable Filter

If you want to save even more money on furnace filters, consider switching to a reusable filter. These filters can be washed and reused multiple times, saving you money in the long run. Just make sure you clean and maintain the filter properly to ensure it continues to work effectively.

By following these cost-effective tips, you can make sure you're using the right size furnace filter without breaking the bank. So, take the time to find the right filter size and start enjoying lower energy bills and a more efficient furnace.

Conclusion: Your Furnace and Your Wallet Will Thank You For Choosing the Right Filter Size

In conclusion, choosing the right size furnace filter is crucial for your furnace's efficiency, your home's air quality, and your wallet. By selecting the proper size filter, you can ensure that your system is working at peak performance, reducing energy costs, and improving indoor air quality. Furthermore, buying your furnace filters online or in bulk can save you even more money, especially if you stick to standard filter sizes.

Remember, a little effort in choosing the right filter size and taking the time to replace them regularly can lead to significant benefits for you and your family. So, don't skimp on this critical aspect of furnace maintenance, and reap the rewards of a comfortable, healthy, and cost-efficient home.

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.