As you may already know, furnace filters are not a one-size-fits-all solution. The size of your filter will depend on your furnace’s model and capacity. Luckily, there are some standard sizes that fit most furnace models. However, it’s always recommended to double-check your furnace’s manual or consult with an expert to ensure you’re getting the right size.

So, what are the most common furnace filter sizes? We’ll cover that along with some useful tips to help you choose the best filter for your home. By the end of this article, you’ll be prepared to make an informed decision that will keep your furnace running smoothly and efficiently for years to come.

Measure Your Furnace Filter: How to Determine the Correct Size

Determining the appropriate size for your furnace filter is crucial to ensure efficient and effective filtration of air circulating in your home. Here is a step-by-step guide on how to measure your furnace filter:

Step 1: Locate your furnace filter. It is usually located near the blower motor, air handler or air intake.
Step 2: Turn off your furnace to prevent any dirt or debris from being stirred up.
Step 3: Remove the existing filter from its housing by lifting and pulling it out.
Step 4: Using a measuring tape, measure the width, height, and thickness of the filter. You can also reference the filter packaging, which should have the dimensions clearly printed.
Step 5: Round up the measurements to the nearest inch. For example, if the filter dimensions are 19.5" x 24.5" x 2", then the filter size is 20" x 25" x 2".

It is important to note that not all furnace filters have the same dimensions. Furnaces are designed to work with a specific size of filter, and using the wrong size can cause problems like reduced air flow or system failure. So, make sure you measure your filter correctly and purchase the right size for your furnace.

The Most Common Furnace Filter Sizes: What Fits Your Home?

When it comes to choosing a furnace filter for your home, it’s important to get the right size. Having the correct size filter will ensure that your furnace operates efficiently and effectively, while also keeping your indoor air quality at its best.

Here are the most common furnace filter sizes:

  • 16x20x1
  • 20x25x1
  • 16x25x1
  • 20x20x1
  • 24x24x1
  • 16x20x4
  • 20x20x4
  • 16x25x4
  • 20x25x4
  • 24x24x4

To determine which filter size fits your furnace, check your owner’s manual or the current filter already in place. Measure the length, width, and depth of the filter to ensure accuracy.

It’s important to note that not all furnace filter brands offer every size option, so be sure to check the availability of filters in your preferred size before purchasing a new furnace filter.

Choosing the right size furnace filter is essential for maintaining a healthy living environment and running an efficient HVAC system. So, take the time to measure and select the correct filter size for your home for a comfortable and healthy living space.

MERV Ratings: What You Need to Know When Choosing a Filter

When searching for a furnace filter, one important factor to consider is the MERV rating. The Minimum Efficiency Reporting Value, or MERV, is a rating system that measures a filter's ability to capture airborne particles of various sizes. The higher the MERV rating, the more efficient the filter is at trapping particles.

Choosing the right MERV rating for your home depends on your individual needs. MERV ratings range from 1 to 20, with 1 being the lowest and 20 being the highest. A MERV rating of 1 to 4 provides minimal filtration and is typically used in residential settings, where the furnace system is not heavily used or the air quality is not a significant concern.

A MERV rating of 5 to 8 is suitable for residential properties, where the furnace is used regularly, and the air quality needs improvement. Filters in this range can capture large particles like pollen, dust mites, and pet dander.

Filters with MERV ratings of 9 to 12 are ideal for commercial properties, where the air quality needs improvement in high-traffic areas like hospitals and shopping centers. The filters in this range can capture smaller particles like mold, bacteria, and fine dust particles.

For superior air quality, filters with MERV ratings of 13 or higher are recommended. These filters are often used in medical facilities, laboratories, and other sensitive environments, as they can capture microscopic particles like smoke, viruses, and bacteria. However, it's important to note that filters in this range may restrict airflow in residential HVAC systems.

Overall, selecting the appropriate MERV rating for your furnace filter will help improve the air quality in your home or business. It's essential to consider the air quality of your environment, the level of air filtration required, and the compatibility of the filter with your furnace system.

Disposable vs. Permanent: Which Furnace Filter is Right for You?

When it comes to choosing a furnace filter, many homeowners are faced with the question of whether to go for disposable or permanent filters. Both options have their advantages and disadvantages that you should consider before making a decision.

Disposable Filters: These filters are made of paper or fiberglass and are designed to be thrown away and replaced every few months depending on the usage level. They are generally cheaper and easier to replace than permanent filters. However, they may not be as effective in filtering out small particles such as pollen and pet dander. Disposable filters also contribute to environmental wastage since they need to be replaced frequently.

Permanent Filters: These filters are made of washable materials such as foam or mesh and can be reused multiple times. They can be more expensive upfront but can save you money in the long run since you won't have to keep replacing them. They are also better at filtering out small particles and can improve indoor air quality. However, they require periodic cleaning, which can be time-consuming.

In conclusion, choosing between disposable and permanent filters depends on your specific needs and preferences. If you have allergies or live in an area with high pollution levels, a permanent filter may be the better option for you. However, if convenience and affordability are your top priorities, then a disposable filter may be the way to go. Ultimately, whichever option you choose, make sure to read the manufacturer's recommendations and replace or clean your filter regularly to keep your furnace running efficiently.

Maintaining Your Furnace Filter: How Often to Replace It and Other Tips

Maintaining your furnace filter is an important task to ensure that your heating and air conditioning system works efficiently. Over time, the filter collects dust, debris, and other particles which can clog the filter, making it difficult for the air to flow through the system. This can lead to poor indoor air quality, higher energy bills, and potentially cause damage to your furnace. Here are some tips on how often to replace your filter and other maintenance tips to keep your furnace in tip-top shape.

How often should you replace your furnace filter?

The frequency of replacing your furnace filter depends on several factors such as the type of filter, air quality, and lifestyle habits. As a general rule of thumb, disposable filters should be replaced every 1-3 months, depending on your lifestyle habits. If you have pets, live in a dusty area, or have allergies, you may need to replace your filter more often. On the other hand, high-quality pleated filters can last up to 6 months or longer. Be sure to check the manufacturer's instructions to determine the recommended replacement frequency for your particular filter.

How to replace your furnace filter

Replacing your furnace filter is a simple task that can be done in a few easy steps. First, locate your furnace filter, which is typically located in the blower compartment or air return duct. Make sure you turn off your furnace before replacing the filter. Remove the old filter and dispose of it properly. Replace it with a new filter and make sure it's properly installed. Turn your furnace back on and you're good to go!

Other tips for maintaining your furnace filter

Aside from replacing your filter regularly, there are other things you can do to maintain your furnace and filter. One important tip is to make sure your air ducts are clean. Dirty air ducts can cause your filters to become dirty more quickly and reduce the efficiency of your furnace. Additionally, you can consider upgrading to a higher-quality filter or investing in an air purifier to improve the air quality in your home. Regular maintenance checks and professional cleanings can also help extend the life of your furnace and filter.

Keeping your furnace filter clean and well-maintained is essential to ensure the longevity and efficiency of your heating and air conditioning system. With these tips, you can easily maintain your furnace filter and keep your home comfortable and healthy all year long.


In conclusion, choosing the right sized furnace filter is crucial for keeping your home comfortable and healthy. The most common furnace filter sizes are 16x25x1, 20x25x1, and 16x20x1, but be sure to check your specific furnace model for the correct size. Upgrading your furnace filter can also improve your indoor air quality, and ultimately, your quality of life. By taking the time to find the right filter for your home, you can ensure your heating system runs efficiently and keeps you and your family comfortable all year long.