Air filters are typically sized by their physical dimensions, which are measured in inches. These measurements specify the filter's length, width, and sometimes its thickness.
The sizing convention helps homeowners and HVAC technicians select the correct replacement filter for their heating, ventilation, and air conditioning (HVAC) systems. The size needed is usually printed directly on the frame of the old filter.
Standard Air Filter Dimensions
While filter sizes vary greatly depending on the HVAC system, there are several common sizes widely used. These dimensions are provided in inches and generally follow a Length x Width format, with thickness also being a crucial factor.
According to standard sizing conventions, some of the common dimensions include:
- 10 x 20 inches
- 14 x 20 inches
- 16 x 24 inches
- 18 x 30 inches
- 20 x 30 inches
- 24 x 24 inches
These figures represent the primary face dimensions (length and width) and are critical for ensuring the filter fits correctly into the designated slot in the air handler or return vent. The thickness, often 1 inch, 2 inches, 4 inches, or even 5-6 inches, is also a key part of the sizing.
Finding the correct size is essential for proper system performance and preventing unfiltered air from bypassing the filter.
