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May  2004

The Rate Debate

Fenestration Attachments–The New Frontier
NFRC to Rate and Label Window Attachments
by Jim Benney

FRC seeks to add fair, accurate, and credible ratings for fenestration attachments such as window film, shades and screens to its product offerings.

The Energy Policy Act of 1992 mandated that the National Fenestration Rating Council (NFRC) “develop energy performance ratings and labels for windows and window systems.” The legislation specifically calls for these ratings to include:
• Specifications for testing procedures and labels that will enable window buyers to make informed purchasing decisions about the energy efficiency of windows and window systems; and 
• Information (which may be disseminated through catalogs, trade publications, labels or other mechanisms) that will allow window buyers to assess the energy consumption and potential costs savings of alternative window products.

Since its inception, NFRC has been successful in developing energy performance rating and labeling systems for residential and non-residential window, door and skylight systems; site-built curtainwall and storefront systems; and, more recently, glass blocks and tubular daylight devices. 

Attachment Ratings
Never Offered Before

Now NFRC is prepared to go where no window-related organization has gone before. It is developing an energy performance rating and labeling system for window attachments.

From window films and screens to awnings, blinds and draperies, window attachments have been an integral part of fenestration systems since our early ancestors hung bear skins across cave openings. There is no doubt that these attachments influence the energy performance of the window system they are attached to–but how? And how do we determine and communicate that impact in a fair and uniform manner?

As a first step, NFRC recently approved a revision to its NFRC 200 document, “Procedure for Determining Fenestration Solar Heat Gain Coefficient (SHGC) and Visible Transmittance at Normal Incidence.” The new version incorporates a methodology for calculating the effect of combining after-market applied window films with referenced fenestration products. The procedure results in ratings for films attached to reference residential and non-residential products.

Procedure Developed 
After Thorough Debate
This new rating has generated no small amount of controversy. The process used for obtaining SHGC ratings for attachments differs from the process that is used by window manufacturers to obtain SHGC ratings. 
But there is no ignoring the attachment industry’s need to have some type of nationally recognized rating methodology. It certainly serves as an excellent tool for comparing the energy performance ratings of various attachment types (especially films and screens)–a public service that NFRC is pledged– and happy–to provide. 
With the technical procedure for rating window films in place, the next step will be to develop third-party certification criteria and labeling requirements. This step provides a fair, uniform and credible means for communicating the energy ratings of fenestration attachments on an NFRC label and in other ways. NFRC will embark on a research program this spring to better understand the needs of the people who will use the new 
fenestration attachments ratings, including consumers, code officials and utility energy efficiency 

The results of this research will be presented at our next set of task group meetings, scheduled for June 22-23, 2004. We’re a consensus organization that relies on the input and expertise of our members and other stakeholders. We urge you to get involved and make your voice heard on this very important issue. 

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