How Furnace Filter Sizes Impact Your Energy Efficiency: What You Need to Know

Are you tired of paying high energy bills every month? Have you considered how your furnace filter sizes can affect your energy efficiency? It's time to educate yourself on the importance of properly sized furnace filters and their impact on your wallet.

A furnace filter serves as a barrier between the outside air and the furnace blower, preventing harmful particles and contaminants from entering your home. But did you know that the wrong size filter can cause your furnace to work harder, leading to increased energy consumption and higher bills?

That's why it's crucial to choose the correct furnace filter size for your system. In this article, we'll discuss how different filter sizes affect energy efficiency and provide vital tips to help you choose the right filter for your home. Stay tuned to save money and keep your home's air clean and healthy.

The Relationship Between Furnace Filter Sizes and Energy Efficiency

The size of your furnace filter plays a significant role in your home's energy efficiency. When choosing a filter for your furnace, you need to consider the filter's size and the efficiency rating.

A filter's size determines the airflow through your furnace and affects the energy efficiency of your heating and cooling system. When a filter is too small, it reduces the airflow, making your system work harder and less efficiently. A filter that's too big will cause the system to overheat, leading to increased energy bills and potential damage to the equipment.

Another factor to consider when choosing a filter size is the MERV rating. The MERV (Minimum Efficiency Reporting Value) rating is a system used to rate the effectiveness of air filters. Filters with a higher MERV rating trap smaller particles and improve indoor air quality. However, filters with high MERV ratings can also reduce airflow and efficiency if they are too small for your system.

When choosing a furnace filter, you should consult your HVAC technician to ensure the filter is the right size and meets your home's specific needs. The HVAC technician can perform a blower door test to measure your system's efficiency and recommend the appropriate filter size and MERV rating to maintain the proper airflow and improve the energy efficiency of your heating and cooling system.

In summary, the size of your furnace filter directly impacts your home's energy efficiency. Choosing the right size filter with an appropriate MERV rating is crucial to maintaining a healthy system and ensuring your home is as energy-efficient as possible.

How the Wrong Filter Size Can Negatively Impact Your Furnace's Performance

Choosing the right furnace filter size is essential for your furnace's optimal performance. Using the wrong filter size can negatively impact your furnace's efficiency and lead to greater energy consumption.

If your furnace filter is too small, it can easily damage your furnace's motor and cause it to fail. The lack of proper airflow due to a small filter can also lead to overheating, which means you'll need to pay for expensive repairs or even replace the entire furnace.

On the other hand, using a filter that is too large for your furnace can also cause problems. It may seem like a larger filter would be better as it could catch more debris, but it can actually create an obstruction in the ductwork and make your furnace work harder to circulate air throughout your home.

This additional stress on your furnace can lead to higher energy bills and decreased efficiency, and can even shorten the lifespan of your furnace.

Ultimately, using the correct filter size is crucial for your furnace's performance and efficiency. Be sure to check your furnace's manual or consult with a professional to determine the appropriate filter size for your specific furnace model.

Choosing the Correct Furnace Filter Size for Your System

Choosing the correct furnace filter size for your system is crucial in achieving optimal energy efficiency. A filter that is too small will let harmful particles through and clog up your system, while one that is too large will not fit properly and will allow air to bypass the filter entirely. Here are some tips to help you choose the correct filter size for your furnace.

1. Check your current filter size: The easiest way to find the correct size is to check the size of your current filter, which is usually printed on the filter itself.

2. Measure your filter slot: If you don't have access to your current filter, measure the filter slot where the filter sits. Make sure to measure the length, width, and depth of the slot to find the correct size.

3. Consult your furnace manual: Your furnace manual will typically provide information about the correct filter size for your system. Consult it to ensure you are using the correct size.

4. Seek professional help: If you are still unsure about the correct filter size for your system, seek the help of a professional HVAC technician.

Using a filter that is the correct size for your furnace will not only improve energy efficiency but also help extend the lifespan of your system. Don't overlook the importance of choosing the right size for your furnace filter.

Additional Factors to Consider When Choosing a Furnace Filter

Aside from the size of the furnace filter, there are other factors to consider before making a purchase. These include:

1. MERV Rating: The Minimum Efficiency Reporting Value (MERV) rating measures the effectiveness of a filter at trapping airborne particles, such as dust, pollen, and pet dander. The higher the MERV rating, the better the filter's performance. However, keep in mind that higher MERV filters may also restrict airflow, leading to reduced energy efficiency and potential damage to your HVAC system.

2. Type of Filter: There are different types of furnace filters on the market, each with its own pros and cons. Common types include disposable fiberglass filters, pleated filters, washable/reusable filters, electrostatic filters, and HEPA filters. Take some time to research and choose the type of filter that best fits your needs and budget.

3. Filter Material: The material of the filter also affects its performance and durability. For example, fiberglass filters are affordable but don't last very long, while pleated filters are more expensive but last longer and offer better filtration. Again, it's essential to weigh your options and choose the filter material that meets your needs.

4. Airflow: Choosing a furnace filter that restricts airflow too much can lead to decreased energy efficiency and increased wear and tear on your HVAC system. Make sure to choose a filter that strikes a good balance between filtration and airflow.

5. Cost: While it's important to choose a high-quality furnace filter, it's also necessary to stay within your budget. Consider the long-term costs of replacing filters and factor in any additional expenses, such as increased energy bills or repairs due to poor filter performance.

By taking these additional factors into account, you can find the perfect furnace filter for your home that maximizes energy efficiency, improves indoor air quality, and fits your budget.

Maintaining Your Furnace Filter to Maximize Energy Efficiency

Now that you know how important furnace filter sizes are for your energy efficiency, it’s also crucial to maintain your filter to keep it working effectively. Here are some tips on how to maintain your furnace filter:

1. Check your filter regularly

It’s recommended that you check your furnace filter every month, especially during peak heating and cooling seasons. This ensures that your filter is clean and not clogged, allowing efficient airflow throughout your home.

2. Replace your filter when needed

Your filter will eventually need to be replaced, and this timing depends on various factors. Generally, it’s recommended to replace your filter every 1-3 months. However, if you have pets, live in a dusty environment, or have respiratory issues, you may need to replace your filter more frequently.

3. Use the right filter

Make sure you’re using the correct filter for your furnace. Using the wrong filter can cause damage to your HVAC system, reducing its efficiency and lifespan.

4. Consider upgrading your filter

If you’re looking to improve your energy efficiency, consider upgrading your filter to a higher MERV (Minimum Efficiency Reporting Value) rating. This means the filter will capture more airborne particles, improving indoor air quality and reducing strain on your HVAC system.

By maintaining your furnace filter and ensuring it’s working efficiently, you can maximize your energy efficiency and save money on your energy bills. It’s a simple yet important task that should not be overlooked!

The Final Verdict

In conclusion, choosing the right size of furnace filters plays a crucial role in maintaining a healthy and comfortable indoor environment while also saving energy and reducing your utility bills significantly. Remember that the size of your furnace filter should correspond with the size of your furnace to ensure optimal performance. It is always recommended to consult a professional HVAC technician to help you choose the perfect size of furnace filter that meets your specific requirements. With the right size of the furnace filter, you can enjoy improved indoor air quality, energy efficiency, and lower utility costs for years to come.

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.