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Furnace Filter Size Chart for 2024

Standard 1 Inch Furnace Filters

1 Inch Air Filters also known as Furnace Filters, HVAC Filters, Air Conditioner Filter and AC Filters. Atomic brand filters are made from Quality materials in The USA. Made in the USA Filters are made of synthetic material and pleated for optimal air flow. Air filters with a Nominal Size of 1 inch thick air filters have an actual size of .75 inches. MERV 8 air filters use Mechanical filtering to filter out particulate from the air flow. MERV 11 and MERV 13 air filters use Triboelectric(or electrostatic properties in addition to mechanical means to filter the air flow.

Air Filter Size Chart

Find Your Filter Sizes Easy in 1" Deep Filters , 2" Deep Filters, 4" Deep Filters See the complete list of furnace filters by Size Brand and MERV.

Furnace Filter Size (Nominal) Actual Size
10x10x1 9.5 x 9.5 x .75
10x20x1 9.5 x 19.5 x .75
10x24x1 9.5 x 23.5 x .75
10x30x1 9.5 x 29.5 x .75
12x12x1 11.75 x 11.75 x .75
12x16x1 11.5 x 15.5 x .75
12x18x1 11.5 x 17.5 x .75
12x20x1 11.5 x 19.5 x .75
12x24x1 11.375 x 23.375 x .75
12x25x1 11.5 x 24.5 x .75
12x30x1 11.625 x 29.5 x .75
12x36x1 11.5 x 35.5 x .75
14x14x1 13.5 x 13.5 x .75
14x15.5x.75 14 x 15.5 x .75
14x18x1 13.5 x 17.5 x .75
14x20x1 13.5 x 19.5 x .75
14x24x1 13.375 x 23.375 x .75
14x25x1 13.5 x 24.5 x .75
14x30x1 13.5 x 29.5 x .75
15x20x1 14.5 x 19.5 x .75
15x25x1 14.5 x 24.5 x .75
16x16x1 15.75 x 15.75 x .75
16x18x1 15.5 x 17.5 x .75
16x20x1 15.5 x 19.5 x .75
16x24x1 15.375 x 23.375 x .75
16x25x1 15.5 x 24.5 x .75
16x30x1 15.5 x 29.5 x .75
16x32x1 15.5 x 31.5 x .75
17x22x1 16.5 x 19.5 x .75
18x18x1 17.5 x 17.5 x .75
18x20x1 17.5 x 19.5 x .75
18x22x1 17.5 x 21.5 x .75
18x24x1 17.375 x 23.375 x .75
18x25x1 17.5 x 24.5 x .75
18x30x1 17.5 x 29.5 x .75
20x20x1 19.5 x 19.5 x .75
20x21.5x.75 20 x 21.5 x .75
20x21x1 19.5 x 20.5 x .75
20x22x1 19.5 x 21.5 x .75
20x24x1 19.375 x 23.375 x .75
20x25x1 19.5 x 24.5 x .75
20x30x1 19.5 x 29.5 x .75
21.5x23.25x.75 21.5 x 23.25 x .75
22x22x1 21.5 x 21.5 x .75
24x24x1 23.375  x  23.375  x  .75
24x30x1 23.5 x 29.5 x .75
25x25x1 24.5 x 24.5 x .75
30x30x1 29.5 x 29.5 x .75
30x36x1 29.5 x 35.5 x .75


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Find Your Furnace Filter by Brand

Click the link for the brand to see the entire collection. Use the search to find your item by Model, Title or Size.

 Whole House Filters by Brand Model Size Actual Size
Lennox Furnace Filters See all
Lennox MERV 16 Filters Sizes
Lennox X6672  16x25x5 15 7/8" x 24 7/8" x 4 3/8"
Lennox X6666 17x26x4 16-5/8" x 26" x 4"
Lennox X6675 20x25x5 19 7/8" x 24 7/8" x 4 3/8"
Lennox X6669 21x26x4 20-3/4" x 25-3/4" x 3-3/4"
Lennox X7935 20x20x5 19-3/4" x 19-7/8" x 4-3/8"
Lennox X8788 20x26x5  20" x 25-1/2" x 4 3/8"
Lennox X8789 17x26x5 16.31" x 25.47" x 4.31"
Lennox X8790 20x21x5 20" x 20-5/8" x 4-3/8"
Honeywell Furnace Filters See all
16x20x4 FC100A1003 16x20x4 15 7/8" x 19 7/8" x 4 3/8"
16x25x4 FC100A1029 16x25x4 15 7/8 x 24 3/4 x 4 3/8
20x20x4 FC100A1011 20x20x4 19 7/8" x 19 7/8" x 4 3/8"
20x25x4 FC100A1037 20x25x4 19 7/8" x 24 7/8" x 4 3/8"
Aprilaire See all
Carrier / Bryant See all
Carrier 16x20x5 FILXXFNC0017 16x20 15 1/2" x 19 7/8" x 4 1/8"
Carrier 16x25x5 FILXXCAR0016 16x25 15 3/8” x 25 1/4” x 5 1/4”
Carrier 20x20x5 CMF2020 20x20 20 3/4” x 20 1/4” x 5 1/4”
Carrier 24x25x5 FILXXCAR0024 24x25 23 3/4 x 24 3/4 x 4 3/8
Carrier 20x25x5 FILXXCAR0020 20x25 20 1/4” x 25 3/8” x 5 1/4”
Carrier MERV 13 Germicidal
Carrier PGAPXCAR1620 16x20x3 17.3x19.9x2.6
Carrier PGAPXCAR1625 16x25x3 17.3" x 24.9" x 2.6"
Carrier PGAPXCAR2020 20x20x3 21.0" x 21.9" x 2.6
Carrier PGAPXCAR2420 24x20x3 24.5 x 21.9 x 2.6
Carrier PGAPXCAR2025 20x25x3 20.9" x 24.9" x 2.6"
Carrier MERV 15 Air Purifier
Carrier GAPCCCAR1620 MERV 15 16x20 17-1/8" x 21-1/2" x 3 5/8"
Carrier GAPCCCAR1625 MERV 15 16x25 17 1/16" x 24 3/8" x 3 5/8
Carrier GAPCCCAR2020 MERV 15 20x20 20 3/4" x 20 1/2" x 3 5/8
Carrier GAPCCCAR2025 MERV 15 20x25 20 3/4" x 24 3/8" x 3 5/8"
Carrier GAPCCCAR2420 MERV 15 24x20 24-1/4 x 21-5/8 x 3-1/2
Toptech See all
Totaline (Goodman) P102-1620 See all 16x20x5  15-3/8" x 21-7/8" x 5-1/4"
Totaline (Goodman) P102-1625 16x25x5 15-3/8 x 25-1/2 x 5-1/4
Totaline (Goodman) P102-2020 20x20x5 20-1/4"x20-3/4"x5-1/4"
Totaline (Goodman) P102-2020 20x25x5 20-1/4" x 25-3/8" x 5-1/4"
Trion Air Bear See all
Skuttle See all

Nominal Filters Size: Understanding Filter Sizing  Could Save You Time and Money

Not understanding the Nominal Filter Size is the primary culprit for incorrectly purchased filters.The Nominal Size is the usually the dimensions used to Label the filter. For instance 16x20x1. These dimensions are a rounded value on the filters actual measurements. The actual measurements on this filter may be 15.5x19.5x.75, but that could vary by brand and manufacturer. So in order to make sure you have the correct size filter, especially if you are replacing with a different brand it is important to confirm the actual size on the filter. When purchasing filters on the internet the Nominal size is usually found in the product title.

Actual Filter Size- The Key to Making the Right Replacement Filter Purchase

The actual size as you might have guessed are the actual dimensions of the filter by length, width and thickness. This size is often on the filter right below the Nominal size and is usually labeled as the actual size. When you are buying a filter online the actual size is sometime in the product bullet point or the product description. If your filter does not have actual dimensions on the outside of the filter, you can measure you filter to get the correct dimensions. Some brands have a foam gasket on the outside of the filter, in this case, you will want to make sure you have a compatible actual size and that it also has the foam to ensure a snug fit. 

Related Furnace Filter Guides

Furnace Filters

16x25x1 Air Filter

16x20x1 Air Filter

20x25x1 Air Filters

How to Choose The Right Home Air Filter Everytime

Buy a Replacement Air Purifier

How Do I Find the Size of My AC Filter?

You can usually Find the Size of Your Air Conditioner filter right on the size of the frame of the filter. The Picture of this 12x12x1 inch air filter has the Nominal size which is the size by which air filters are generally sold. on the right of the filter it also includes the actual size of the filter which are the true measures dimensions of the filter by lenght width and depth. See air filter image:

Complete List of Furnace Air Conditioner Filters by Size

If there is no size on your current AC filter, you can measure the legnth width depth of the filter and the filter to find the Actual Size of your filter with the Corresponding Furnace Filter size in the Furnace Filter Size(Nominal Size) Chart.

What is a MERV Filter?

MERV is a not a brand or type of filter but scale for ranking air filters based on their particle removal efficiencies. MERV stands for the Minimum Efficiency Reporting Value.  The MERV scale ranges from 1 to 20.

Is MERV 8 a Good Filter?

According to the EPA, most home HVAC systems use a low MERV (1-4) fiberglass furnace filter that has a nominal size of 1” thick. Upgrading this AC filter to a medium efficiency filter (MERV 5-8) can have a significant effect on improving the air quality in your home. MERV 8 being at the top of this scale would be a good choice for improving the air quality in your home. For allergy suffers a higher MERV filter would be a better alternative.

What is a Good Allergy Filter?

When it comes to smaller particles that can irritate allergy suffers, higher efficiency filters (MERV 9-12) will work even better at improving air quality. What does MERV 11 mean. MERV 11 is a superior residendial air filter which will filter a very high percentage of particles as small as 3.0 to 1.0 μm each time the air passes through the filter. This includes particles such as Legionella, Humidifier dust, Lead dust, Milled flour, Auto emission particulates, and Nebulizer droplets.

Is A Higher MERV Rating Better?

A true high efficiency filter (MERV 13-16) can reduce indoor particles by as much as 95 percent. Filters with a High Efficiency Particulate Air (HEPA) rating, (or MERV 17-20) are the most efficient. You may need to consult with a local heating and air technician or the manufacturer of your central air system to confirm which (or if ) high efficiency filters will work with your system. If you can’t switch to a more efficient filter, running the system continuously by switching the thermostat fan from “Auto” to “On” has been shown to reduce particle concentrations by as much as 24 percent.

Furnace Filters Air Flow Direction

The Air flow arrow on the side of your filter indicates the correct air flow direction of the air entering your furnace equipment. The correct direction of the arrow is facing away from the return duct that carries the air in need of heating or cooling and toward the HVAC equipment.

Air enters the front of the filter and exists the back of the filter which faces the furnace or HVAC. Air filters were initially designed to protect your expensive HVAC equipment. Even through there are now filters also meant to protect air quality the filter is located before to equipment to protect your system.  Air filters usually have support on the back side of the filter which is the direction of the air flow from the front of the filter to the back.Many filters will have metal wire on the back of the filter.

What Happen if the Filter is Backwards?

The furnace filter was designed for the air to flow in one direction which is why many filters have metal wire on the back of the filter to prevent the filter from collapsing. A filter installed backwards will restrict air flow in your air handler causing the system to work harder to make up for the decreased airflow. 

What happens if you put an air filter in the wrong direction is your furnace is forced to blow air through the non-porous end of a filter. More energy will be required to move air through the system. The blower will be overworked increasing the energy cost  for your heating and cooling. This could also have long term effects on the life of your HVAC system.

What Filter do you need. Leave us a comment or contact us and we will help you find your filter.


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