Learn About the Air Filter Size Chart | Airzey

When it comes to improving indoor air quality in your home, air filters are essential, but how are you supposed to know what size air filter you should get? 

Air filters come in various sizes to fit different heating, ventilation, and HVAC systems. It's critical to select the correct size air filter for your system to ensure proper airflow, filter out airborne particles, and maximize the efficiency of your HVAC system. An air filter size chart can help determine the appropriate size air filter for your specific system.

These charts typically list the dimensions of various air filter sizes and the corresponding HVAC system models they fit. You should always carefully measure the dimensions of your current air filter and consult the air filter size chart to ensure that you purchase the correct size air filter for your system. 

This process is more complex than you might think, which is why Airzey is here to help. Keep reading to find out more!

Sizes of Air Filter

You'll want to keep a few factors in mind when purchasing an air filter, and size is certainly one of them. It's standard procedure for the air filter business to manufacture air filters smaller than their slot or filter frame so you can slip them into place without getting damaged.

Let's go over some of the more common air filter sizes below according to industry standards:

Nominal Size

Nominal size, when it comes to air filters, refers to the rough dimensions of the filter, which are usually expressed in inches. These dimensions are typically produced in length, width, and depth (or thickness). The nominal size of an air filter is not necessarily the exact size of the filter but rather a rough approximation of its size. The actual size of the filter may vary slightly from the nominal size due to manufacturing tolerances and differences in the filter's materials.

Actual Size

The actual size of an air filter refers to its precise dimensions, including its length, width, and depth. The actual size differs from the nominal size, as the nominal size is typically just a rough approximation of the filter's dimensions.

True To Size

True-to-size air filters are the exact size specified in their nominal size. In other words, the actual dimensions of a true-to-size air filter will match the dimensions listed on the filter packaging or in an air filter size chart. True-to-size air filters are designed to fit your HVAC system with minimal variance in size, ensuring proper airflow and maximizing overall efficiency.

Various Methods to Determine the Size of Air Filter

You can use a few different methods to determine what size air filter will fit with your HVAC system. Let's go over these methods now.

Observe the Label on the Frame of the Filter

The simplest way to determine what size air filter you need is to remove the old air filter from your HVAC system and measure the width of the opening where you will place the new filter. Most air filters contain instructions that list the exact measurements and explain how to install the filter correctly. If you're unsure, you can always check the manufacturer's website for clarity.

Your Air Filter's Size

You can check the size of your HVAC system's air filter by measuring its length or width with a ruler or similar measuring device. This can be helpful if there isn't an official label on your air filter or if you're just not sure what the exact dimensions of your air filter are. You can also compare the size of your new air filter with that of your old one, as they should be roughly the same size.

Determine Your Air Input

Air input is certainly important to consider when determining your air filter size. To select the size of your air input, you will need to measure the width and height of the opening where you will install the air filter in your HVAC system. These measurements should be taken in inches and multiplied to calculate the air input's total square inches. 

Once you have figured out your air input, you can use an air filter size chart to find the appropriate air filter size for your HVAC system.

How to Measure

Step 1: Turn Your AC Off

This step is optional, but many people prefer to turn off their AC before attempting to install a new air filter.

Step 2: Measure Your Filter

Using a ruler or other measuring device, measure your air filter's exact length, width, and depth. For example, the length of your new air filter might be 15.5", while the width might be close to 24.6" with a depth of 0.75".

Step 3: Round Up

In order to calculate the nominal size of your filters, round up each filter dimension to the next whole number.

What are the Most Popular HVAC Filter Sizes?

If you've wondered what the most popular HVAC air filter sizes are, you've come to the right place. There is a wide range of sizes available for HVAC systems.

Some of the most popular 1-inch air filters include:

• 14x30x1
• 16x20x1
• 16x25x1
• 20x20x1
• 20x25x1

If it's thicker filters you're looking for, some of the most popular 4-inch air filters include:

• 16x25x4
• 20x20x4
• 20x25x4

Frequently Asked Questions:

How do I know what type of furnace filter to buy?

There are several factors you should consider when determining the type of furnace filter to purchase for your HVAC system. Size, for example, is essential, as getting the wrong filter size could potentially damage your system. 

Also, consider the furnace filter's MERV rating, which is used to measure the effectiveness of a filter in removing contaminants from the air. 

A third factor to consider is price. High-quality filters will cost more upfront, but they may also last longer and provide better air filtration, resulting in long-term cost savings.

What should I look for when choosing a furnace filter?

When choosing a furnace filter, there are a few key factors to consider to ensure that you select a filter suitable for your HVAC system. Pay attention to the size of the filter, the MERV rating, the specific type of filter, and the price.

Do all furnace filters need to be replaced every year?

The short answer is that it depends. Fiberglass filters should be replaced every month or two, while pleated filters can typically last for up to three months before needing to be replaced. Washable filters can be cleaned and reused, but you'll still probably need to replace them every three to six months. 

If you have pets or live in a heavily polluted area, you will need to replace your furnace filter more often. According to the Department of Energy, replacing a clogged or dirty furnace filter can increase the efficiency of your system by 5 – 15%. For this reason, replacing your filter at least once every three months is worth it.

Are there any benefits to having a high-efficiency furnace?

There are several benefits to having a high-efficiency furnace in your home. High-efficiency furnaces are designed to use less energy to produce heat, which can result in lower energy bills and a smaller carbon footprint. High-efficiency furnaces also tend to have longer lifespans than less efficient ones.

Final Thoughts

An air filter size chart is a valuable tool in determining the appropriate size of an air filter for your HVAC system. You should always make sure you select the correct size air filter so that your HVAC system continues to run efficiently. 

There is a wide range of sizes available for air filters, and the most popular sizes can vary depending on the specific needs and dimensions of different HVAC systems. Using too small or large of a filter can disrupt the airflow in your home and may cause problems with your HVAC system. By taking the time to select the right size air filter, you can help ensure that your HVAC system is in good shape.