Information about Window Tint Heat Rejection.
Also known as- Infrared Rejection, IRR, IR Rejection, Infrared Energy Rejection
In Short - Buyer beware - IRR numbers can easily be manipulated.
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
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
IWFA Official Statement - Misuse of Infrared Rejection Values
Often Infrared (IR) rejection values are reported in a way that may mislead consumers. In response to
such non-standard publication of solar IR rejection specifications, the IWFA has defined Infrared Energy
Rejection ("IRER") as the value to be used to clearly state IR rejection potential of a product to
consumers.
Infrared Energy Rejection ("IRER") is technically defined as a measurement of the percent of solar
infrared energy rejection over the wavelength range from 780-2500 nanometers.
Infrared Energy Rejection (IRER) is a measurement of infrared rejection over the IR range of 780-
2500 nanometers. IRER takes into account that a portion of absorbed IR energy will be reradiated into
a car, home or building. IRER is similar to Total Solar Energy Rejection (TSER), but only involves the
solar infrared range. Again, the IWFA defined IRER in response to non-standard publication of solar IR
rejection specifications in the window film industry.
Calculating IRER values in the manner articulated below (the "IRER Endorsed Testing Method") will be
deemed to comply with IWFA's Advertising Policy. Product or advertising claims based on other
methods for calculating IRER values will be deemed to violate these Policies, unless the party making
the claim can adequately substantiate both the methodology and the actual calculated values.
Given that IR rejection claims have a significant propensity to mislead consumers, the IWFA Technical
Committee developed a reasonable, credible, and non-misleading way to calculate IRER values by using
values derived from testing methods set out in other widely accepted and reputable industry testing
methods.
The IWFA Board endorses the following test method for calculating IRER values:
such non-standard publication of solar IR rejection specifications, the IWFA has defined Infrared Energy
Rejection ("IRER") as the value to be used to clearly state IR rejection potential of a product to
consumers.
Infrared Energy Rejection ("IRER") is technically defined as a measurement of the percent of solar
infrared energy rejection over the wavelength range from 780-2500 nanometers.
Infrared Energy Rejection (IRER) is a measurement of infrared rejection over the IR range of 780-
2500 nanometers. IRER takes into account that a portion of absorbed IR energy will be reradiated into
a car, home or building. IRER is similar to Total Solar Energy Rejection (TSER), but only involves the
solar infrared range. Again, the IWFA defined IRER in response to non-standard publication of solar IR
rejection specifications in the window film industry.
Calculating IRER values in the manner articulated below (the "IRER Endorsed Testing Method") will be
deemed to comply with IWFA's Advertising Policy. Product or advertising claims based on other
methods for calculating IRER values will be deemed to violate these Policies, unless the party making
the claim can adequately substantiate both the methodology and the actual calculated values.
Given that IR rejection claims have a significant propensity to mislead consumers, the IWFA Technical
Committee developed a reasonable, credible, and non-misleading way to calculate IRER values by using
values derived from testing methods set out in other widely accepted and reputable industry testing
methods.
The IWFA Board endorses the following test method for calculating IRER values:
- Infrared Energy Rejection: (I- SHGC780-2500 nm) expressed as a percent
- Calculated using NFRC 200 spectral data for 780-2500 nm only and LBNL Window program.
- Other IR rejection values used in the industry may use either an average IR rejection or may be measured in a very narrow wavelength range. While these values may be accurately calculated they are often misleading to the uneducated consumer.
- For the purposes of education, these values may be printed in association with the IRER value.