A Size Guide for Selecting the Right Air Filter. The air filter is an essential component of the furnace. You might never give the furnace filter a thought until it cools your room well in the summer and keeps your spaces warm in the winter. One of the common confusion about air filters is related to their size.
You might want to ask, how do I know what size air filter I need? Here is a size guide that will help you select the right air filter.
Standard Air Filter Dimensions
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Common terms like “Standard stock size” air filters often confuse people when buying air filters. There are several standard sizes in air filters like 16x20x1, 20x20x1, 16x25x1, and 20x20x1. Every HVAC system needs a filter of a specific size essential for the HVAC system to perform efficiently.
Most furnace systems use standard size filters, but that is not a universal rule. You need to know the exact dimensions of the air filter inside the HVAC system to select the right filter.
Standard Size Filter Facts- air filter actual size
- There are around ten or more standard sizes available in the market, and most vendors stock these sizes. If your HVAC system requires a different sized filter, you need to contact the manufacturer and specify your requirement or check the air filter size chart for guide.
- There are two different sizes in air filters – Nominal size and Exact size. The Nominal size is an approximate size, such as 16x36x1 air filters – Merv 8, where MERV rating refers to its efficiency. A 16x36x1 air filter is designed to fit the standard 16x36x1 air filter slot.
- The Exact size is always smaller than the Nominal size. It refers to the exact dimensions of the air filter. For example, the exact size may be 16x36x1 air filters – Merv 8 15.5 x 35.5 x 1. Since the Nominal Size and Exact size confuses many. It is always good to measure the exact dimensions of the air filter before purchasing a replacement filter.
- There can be slight variances in the sizes of air filters from different manufacturers. However, that is not a big problem. The air filter should not be a tight fit. You should be able to slide in the air filter easily in the slot without any struggle.
- Thousands of exact filter sizes can be used in the HVAC unit. Hence, it is not always easy to find the correct filter size online, like standard filter sizes. In that case, you can order a custom size air filter for your HVAC unit. However, you need to have a perfect measurement of the air filter before ordering a custom one. You can always refer to the goodman air filter size guide for details.
How to measure air filter
Are you looking for how to measure dimensions of your air filter? If yes, you are in the right place. The air filter has two sets of dimensions – actual and nominal. The exact dimensions of the filters refer to the measurements of the height, width, and length of the filter.
Sellers round off the nominal dimensions to the nearest 1″ measurement. These are the dimensions used for selling air filters. If the filter’s actual dimensions are 15.5 x 35.5 x 1, you need to look for a 16x36x1 air filter – Merv 8.
Finding the right-sized filter is vital as improper filter sizes lead to energy waste. The furnace filter size finder and size guide presented above would help clear doubts related to air filter sizes and help you buy the right-size air filters with confidence.