IWFA Issues Clarification on How to State IR Rejection Values

January 24th, 2024 by Casey Flores

The International Window Film Association (IWFA) is doing a bit of housekeeping regarding how its members market window film. 

In a message to all of its manufacturer, dealer and distributor members, the association wants to clarify how its members should tout a film’s infrared rejection market film’s ability to block infrared values to consumers.  

“Consumers need a way to compare one product from three different manufacturers and compare which is the best infrared reflector,” says IWFA executive director Darrel Smith. “IR rejection alone is not a measurement of the total heat control of a glazing system. You have to use the Solar Heat Gain Coefficient.” 

Smith did not specify where he had seen the misleading window film information—only that he and others had noticed it and saw fit to correct the record.  

“People are trying to take a thin slice of the infrared curve,” Smith says. “They thought ‘oh you’re blocking 98% of all the heat coming through the window’ – no. Infrared is approximately half of the solar energy. Consumers were seeing that and while those saying that weren’t lying, the statements were incomplete. Infrared goes from 780 nanometers to 2,500 nanometers. If their product blocked 900-1,000 nanometers they’d report that it would block 98% in that range, they might be right.” 

Smith says all IWFA members agree to put out data on infrared rejection in the stated way when they sign up for the association—it is in their agreements.  

The official statement clarifying how members can market the information is below:  

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