What Size Are the House Air Filters?

The actual size of an air filter is usually slightly smaller than its nominal size. This is known as undermining, and it applies to all filters 1 and 2, which are lowered by a quarter of an inch to provide a little headroom and ensure they fit into the air return without being too large. This includes custom sizes, so a 27-8 x 23-7 x 2 filter actually measures 27-¼ x 23-7 x 1-¾. Air filters are labeled with three-part dimensions.

The first number is its length, the second is its width, and the third is its depth or thickness. To measure the length and width (L x W), you should take the smallest measurement first. This way, you can reduce the number of unique air filter sizes on the market by half, as you don't need to have a size of 20 x 30 and one of 30 x 20 as two different products. When it comes to air filtration, many people are confused and rarely ask questions about it.

To make sure you find the perfect size for your home, you should watch the video for guidance on using the oven filter size chart and listen to expert advice to avoid common mistakes. When searching by brand, such as Lennox or Carrier, to find a Carrier oven filter size by model number, you can use a Carrier filter size search in the table above or with a Lennox size search up. If an oversized filter gets stuck where it doesn't belong, it can damage the HVAC system and not clean the air properly. These numbers refer to the standard size of your home's return ventilation grilles, responsible for controlling the movement of air to and from the HVAC unit.

Electrostatic filters create charged particles that attract other particles in the air for better filtration, but they can sometimes restrict airflow, which can cause system and air quality problems. Household air filters are those that are inserted into the wall when air is returned; although, in some homes, they can go to the ceiling or to the duct network itself. You also don't want to place a 1-inch air filter in a 2-slot slot because air takes the path of least resistance and will flow around the filter rather than through it if it's not the right size. Watching a video for step-by-step instructions on how to find out your actual dimensions and obtain your nominal size is essential for making sure you get the right filter size for your HVAC system. Understanding more about air conditioner and oven filter sizes can ensure that you find the perfect size for your home.