A MORE PRACTICAL CONDENSATION RATING

Article Posted in WINDOW+DOOR, July 26, 2021
By: Dennis Anderson

 

 

NFRC MOVES TO A MORE PRACTICAL CONDENSATION RATING

The National Fenestration Rating Council and its membership developed the condensation resistance rating more than 20 years ago. While this rating was fair, accurate and credible, the rating only provided information to compare which products had the higher rating value.

The shortcoming of the NFRC condensation resistance rating was that the value could not be used to predict the likelihood of condensation forming on the product based on the following factors: relative humidity in the home, dew point temperature in the home or expected exterior air temperatures during the coldest days of the year.

NFRC and its membership fixed that. The newly approved Condensation Index (CI) allows the consumer, manufacturer, building owner or architect to find the fenestration product that best reduces the potential for condensation based on where that window, door or skylight will be in the U.S. or Canada.

In 2018, Jeff Baker shared a research study by Hakim Elmahdy with the NFRC condensation resistance task group. This paper, A Universal Approach to Laboratory Assessment of the Condensation Potential of Windows, held the key that ultimately resulted in the new NFRC CI rating.

The CI rating provides the point at which the window will potentially form condensation. This allows the end user to determine the minimum CI rating needed to reduce the likelihood of condensation forming, using Table 7-1 from the NFRC 501-2020: User Guide to the Procedure for Determining Fenestration Product Condensation Index Rating. The desired rating for a specific city or region in North America can be determined with two of the following three indicators: the winter design temperature, the relative humidity (RH%) or the dew point temperature.

 

Article Posted in WINDOW+DOOR, July 26, 2021

 

Learn more about Westeck’s high performance Aluminum Windows and Balcony Doors

Learn more about Westeck’s high performance Vinyl Slider Windows