When it comes to air filters, the nominal size is the rounded value used to label it. This size includes the height, width, and depth of the filter. In some cases, the measurements of an air filter are not indicated as exact physical dimensions. Instead, a model number may be used to identify the size.
If you have the model number, you can easily find out the dimensions. If your air conditioning system uses a whole-house filter, which is usually located near the central furnace or air conditioning unit, then the model number will likely be present instead of the dimensions. MERV ratings range from 1 to 16 and indicate how effective an air filter is at trapping particles. According to Owen, this range “ranges from filters that can catch a golf ball, I'm exaggerating a bit, to filters that catch just about everything.” Interestingly, 70% of what Filterbuy sells does not fall into the 10 most common air filter sizes. When buying an air filter online, it is important to note that they come in two sizes: nominal size and actual size. Nominal size is often used to label the filter and is a rounded value above the actual size.
These filters are installed on wall-mounted return air vents or on the air handler. It is important to make sure that the filter fits snugly into the air filter compartment with a little space around the edges. If it is too small, it will be loose and some of the air (and dirt) will not pass through. Most people won't be able to find their desired size air filter at their local home improvement store. If you live in an old house with a non-standard sized air return frame, you might want to use waterproof foam tape to slightly increase the dimensions of your favorite filter or order a custom-sized air filter. Improperly sized air filters can overload your air conditioning system, damage it, and increase your energy bills.
Therefore, it is important to measure your filter for yourself if the dimensions are too faded to read or there's no air filter in sight. In conclusion, when choosing an air filter for your home or business, it is essential to know both its nominal and actual sizes. This will ensure that you get a filter that fits properly and provides optimal protection against dust and other airborne particles.
