If you're looking to replace your air filter, but don't know what size you need, there are a few steps you can take to identify the correct size. To start, if your current filter does not have a dimension indicated on the frame, use a measuring tape to record the length x width x depth to find the actual size. Then, round these measurements to the nearest inch to find the corresponding nominal size, which will be easier to locate when you search online. In most cases, the dimensions of the air filter will be printed on the side of the filter.
It's important to understand that air filters come in two sizes: nominal size and actual size. Not understanding these numbers can lead to consumers buying a filter that doesn't fit their oven or air conditioning system. To avoid this, make sure to check the product vignette or product description for the actual size before making your purchase. There are thousands of sizes of air filters available, and manufacturers of heating, ventilation and air conditioning systems often make it as complicated as possible.
As a result, it's important to double-check your measurements before buying a new filter. We recommend removing the existing filter and measuring the filter to confirm the actual dimensions. If standard sizes don't fit your needs, you can also build a custom air conditioner or oven filter. Installing several filters on top of each other can damage the air conditioning system, since they are not designed to withstand the level of air flow obstruction.
On the other hand, 4, 5, or 6-inch air filters are found in whole-house filters that are installed in an air controller. To find out what size air filter you need for your air conditioning system, use a measuring tape to measure the length, width, and depth of the inside of the air filter vent. Usually, air controllers are installed near the air conditioning system, and in some homes, they are installed in ducts.