When it comes to air filters, it is important to understand the difference between nominal and actual sizes. Nominal size is typically used to label the filter and is usually a rounded value of the actual filter size. For example, a 20x30x1 filter may be labeled as such, but when measured, it will be smaller than the nominal size. If the filter frame is not properly sized or installed, it can lead to air leaks and reduce the filter's efficiency. Using a smaller filter can allow contaminants to pass through and enter your home's air and air conditioning system. When you need to replace your boiler filter, it is essential to know what size air filter you need.
If you are unable to determine the proper dimensions of the air filter, you may be able to find them in your HVAC manual. If an air filter is too small, gaps will form and contaminants will be able to bypass the filter material. Air conditioning filters come in many different sizes, so it can be difficult to know which one you need. These filters are designed for use in air conditioners, ovens, electronic cabinets, computer systems, and small equipment where it is necessary to capture smaller particles of dust and dirt from the air. Additionally, if there is any resistance to airflow caused by an incorrectly sized filter, it can put unnecessary stress on the air conditioning unit and increase energy bills. When installing an air filter, it should fit snugly into the compartment with some space around the edges.
If you cannot read the dimensions or there is no existing filter to measure, you will need to measure it yourself.