Save 10%
Fast-Free Shipping * contiguous US - All Sizes
Manufacturer Direct
Nordic Pure will be closed Monday, 9/07. We look forward to serving you again on Tuesday, 09/08!
Nordic Pure will be closed Monday, 9/07. We look forward to serving you again on Tuesday, 09/08!

What is Nominal Size vs Actual Size?

Understanding the difference between nominal size and actual size is crucial when selecting the right air filter for your home. The nominal size is a simplified, rounded figure that describes the filter’s dimensions for easy reference. In contrast, the actual size is the precise measurement of the filter, which is usually slightly smaller. For instance, when you see a filter size labeled as 16x25x1, that is its nominal size.

When it comes to air filters, the nominal size can often be misleading if you don’t also consider the actual size. For example, an air filter labeled 16x25x1 might have actual dimensions closer to 15.5×24.5×0.75. This slight difference exists because the nominal size is meant to make it easier for consumers to identify and purchase filters, while the actual size reflects the true measurements, which are crucial for ensuring a proper fit.

Nordic Pure Air Filter Dimensions example photo

It’s essential to measure both the existing filter and the filter housing in your HVAC system to ensure compatibility. If you rely solely on the nominal size, you might end up with a filter that doesn’t fit snugly, potentially allowing dust and debris to bypass the filter. This can reduce the efficiency of your HVAC system and decrease the air quality in your home.

When measuring for a new filter, start by removing the old one and measuring its dimensions. Note the length, width, and depth, and compare these measurements to the actual size listed on the new filters. Ensuring that your new filter’s actual size matches your measurements will help maintain the efficiency and performance of your HVAC system.

In summary, always consider both the nominal size and actual size when purchasing an air filter. For example, if your filter housing requires a 16x25x1 filter, check the actual dimensions to confirm a proper fit. Understanding these differences will help you keep your home’s air clean and your HVAC system running smoothly.

Share:

More Posts

Worst Air Quality Cities in Oklahoma

Oklahoma’s air quality can vary widely from one community to another. Large metro areas, oil and gas activity, agriculture, highways, dry weather, ozone, dust, and

© 2026 Nordic Pure /Designed by:LaunchUX