This Is The Prestige Truth!

On-Angle Performance Measurements -My Angle
Published July 27, 2008 Commercial , Consumer Information , NFRC , Residential , Technical , Window Film Industry 2 Comments Tags: energy rejection, prestige window film, total solar energy rejected on-angle, Window Film

Well I guess it's about time for me to address the whole "on-angle" Total Solar Energy Rejection measurement. As many of you are aware it is a measurement that is currently marketed by 3M to show the performance of their Prestige Window Film line. The whole premise is that the window film industry has always tested and derived the Total Solar Energy specification at 90° perpendicular to the glass. 3M reasons that the sun does not reside at 90° throughout the day, especially at the hottest part of the day, thus the need to create a film that in their mind performs better "on-angle." So the need for an "on-angle" measurement arises and subsequently the specification finds its way into their marketing literature.

Despite the fact that the window film industry has never promoted such a measurement and the NFRC does not post angular performance data on the product certification labels, the general public is left to assume that this is a common measurement that sets one product apart from all others. The assumption gets propagated further when window film dealers add inaccurate statements and insert fiction into what is fact. For instance one dealer writes a rebuttal on their website in response to the statement:

3M's total solar energy on angle spec is not supported by the National Fenestration Rating Counsel Dealer's Response: This is true but this is new technology. No other manufacturer (glass or window film) can rate their product this way. The two hundred layers in the new 3M Prestige window films with nano technology make this new on angle specification possible. All window film manufacturers measure the total solar energy rejected at a 90 degree angle to the glass. Let us separate fact from fiction here…

Fact: The NFRC does not support the Total Solar Energy Rejection On-Angle specification. All manufactures measure the total solar energy rejected at a 90 degree angle to the glass.

Fiction: The statement that this is new technology and that no other manufacturer (glass or window film) can rate their product this way. Also the statement that it is 3M's multi-layer nano-technology that make this new angular specification possible.

The reality is that any manufacture can easily report their performance ratings this way, if they wanted too. This specification is not made possible by the unique construction of Prestige Window Film's multi-layer technology nor is the on-angle measurement a new measurement. Lawrence Berkley Laboratories has had software available for many years that gives angular performance data of window coatings and window films on almost any glass type available. This software and the measurements that result from it are recognized by the Department of Energy (DOE). 3M did not invent this measurement and neither did any other window film manufacturer for that matter. So let's use this LBNL software and run our own test comparing "on-angle" performance data of a few films. This particular test was run on clear single pane glass .120 inch in thickness with some 70% vlt films that have their specifications listed.

Sun's Angle	SHGC @ 0°	SHGC @ 30°	SHGC @ 60°	SHGC @ 80°	SHGC @ 90°
Prestige 70	0.503	0.499	0.427	0.188	0.00
Vista VS 70	0.476	0.471	0.404	0.178	0.00
VKOOL70	0.440	0.435	0.373	0.164	0.00