---
title: "What Is Air leakage rating? Window and Door Glossary"
description: "The air leakage rating shows how much air passes through a closed window or door, measured in cubic feet per minute per square foot. Lower is tighter."
url: https://honeyrock.multisites.ai/glossary/air-leakage-rating
publisher: Honey Rock Window and Door
phone: +1-214-484-9982
quote: https://honeyrock.multisites.ai/contact-us
---

# Air leakage rating

The air leakage rating shows how much air passes through a closed window or door, measured in cubic feet per minute per square foot. Lower is tighter.

Even a closed window can let air through the seals and joints. The air leakage rating measures that flow under a standard test. A lower number means a tighter product, less draft and less strain on your air conditioning.

The figure sits on the [NFRC label](https://honeyrock.multisites.ai/glossary/nfrc-label) with the [U-factor](https://honeyrock.multisites.ai/glossary/u-factor) and [SHGC](https://honeyrock.multisites.ai/glossary/shgc). Do not mix it up with a leak from rain. Water is a separate test. Good weatherstripping, a rigid frame and correct flashing all help a unit stay tight after install. For product comparisons, see our guide on planning a window and door project.

[Where it mattersEnergy-efficient windows for Texas](https://honeyrock.multisites.ai/energy-efficient-windows-texas)

## Related terms

-   [NFRC label](https://honeyrock.multisites.ai/glossary/nfrc-label)
-   [U-factor](https://honeyrock.multisites.ai/glossary/u-factor)
-   [SHGC (Solar Heat Gain Coefficient)](https://honeyrock.multisites.ai/glossary/shgc)
-   [Flashing](https://honeyrock.multisites.ai/glossary/flashing)

## Sources

1.  [NFRC: National Fenestration Rating Council](https://nfrc.org/)

![A modern home with wide glass doors lit warm at dusk beside a pool](https://honeyrock.multisites.ai/_astro/dusk-modern-home-pool-01.CeePxgPr_Z2giQin.webp)

## Let’s frame your view.

Send your plans or a few photos of the openings. We will help you choose the system, the brand and the glass.

[Start your project](https://honeyrock.multisites.ai/contact-us)[or call (214) 484-9982](tel:+1-214-484-9982)