American Architectural Manufacturers Association

Website Quick Tip: Using the CRF Tool

July 31, 2012

Each month, the AAMA e-News will feature Website Quick Tips that show web users how to navigate portions of the AAMA website, including Members Only. This month's Quick Tip details how to use the Condensation Resistance Factor (CRF) Tool, which is intended to provide general guidance on suggesting a minimum CRF based on a project-specific set of environmental conditions.

The calculations used to determine the CRF rating are based on the procedures outlined in AAMA 1503-09, Voluntary Test Method for Thermal Transmittance and Condensation Resistance of Windows, Doors and Glazed Wall Sections.

To access the CRF tool, first navigate to Technical Services and then CRF Tool, which is the fifth link on the dropdown menu. Or, you can click on the hot button located on the left side of the web page.


On the CRF Tool web page, scroll down to the bottom of the page and read the disclaimer. Once you are finished, click the green “Submit” button.

To calculate the CRF, enter the project-specific information in each of the three boxes requiring user data: outdoor air temperature (°F), indoor air temperature (°F) and indoor relative indoor humidity (percentage entered as a whole number). 

For outdoor air temperature, select the ASHRAE 99.6% Heating Dry-Bulb (DB) Temperature from the nearest city to your project’s location using the Major U.S. Cities and State Capitals chart located on the page.

Once all three values are entered, click the green “Submit” button. The suggested minimum CRF rating, along with the dew point temperature, will be displayed at the top of the page.

For instance, for a project location in Chicago (using -5 as the outdoor air temperature), with a typical indoor temperature of 70 degrees and a relative indoor humidity of 40 percent, a CRF of 67 will prevent most condensation.

View the CRF Users Guide for more information on how CRF calculations are derived.

If you would like to suggest Website Quick Tips to be featured in the AAMA e-News, please contact Sam Sinkhorn, AAMA’s Communications Coordinator.

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