Saturday, July 26, 2014

DOE’s Decision Regarding Window Attachments and Rating, Certification and Labeling Programs

Posted by Webmaster on 18. September 2012 21:49

The Department recently reviewed Section 121 of the Energy Policy Act of 1992 (EPAct), which mandates that a “voluntary window rating program” to develop “energy rating and labels for windows and window systems” be developed by the National Fenestration Rating Council (NFRC).  Pub. L. 102-486 § 121(a) (1992), codified at 42 U.S.C. § 6292 note.

DOE reviewed this section to determine if window attachments fell under the “voluntary rating program” developed by NFRC or whether another entity could develop ratings, certification and labeling systems for window attachments. The Department reviewed the statue, legislative history, technical data, and letters from the NFRC and the Window Covering Manufacturers Association.

Section 121 applies only to windows and window systems.  However, window attachments are neither windows nor window systems. Therefore, the Department determined that EPAct Section 121 is inapplicable to window attachments.

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  • wd said,

    My comments:
    1)As regards Section 121 ("Window attachments are neither windows nor window systems for purposes of energy rating labels")
    It seems there are more fundamental issues here.  Rating labels could be an outcome once the options for energy saving are quantified and evaluated in a fully operational context.  The first order of business ought to be to identify the most effective energy savings options of window attachments available.  Here 'available' means technically known, not merely limited to already marketed products.  Options known to produce lesser savings should be examined in later rounds.  The top tier savings projects should be subjected to an evaluation process that includes a range of incident sunlight angles and ambient temperatures.  Once that is quantified, the evaluation should consider other factors such as asthetics, interior lighting effects, dependence on operator behavior, operating adjustments required, cost, life in use, and robustness in the face of the enviornment.  All of this would be needed input to the rating, certification, and labeling issues.  It might take a while to complete the ratings process but the quantification of savings alone could help guide customers in the meantime.

    2) The most effective attachments for reducing air conditioning load will be those mounted outside the window.  The effectiveness of the device may depend on the angle of incidence of sunlight.  The quantification of savings would need to be over a range of incident angles rather than a single angle.  This way, a consumer would know which set of savings numbers would apply to his or her situation.

    3)Savings reported should be NET savings.  Some projects save energy in one season but hurt savings in another season.  An example might be a window film that reduces air conditioning load in summer but also reduces free heating in the winter.  The net savings should be reported.  Also, if a device requires external energy, this should be considered in the net savings.  If a device requires control equipment, this should be considered in the purchase price along with any external energy consumed.

    4)Maintenance costs.  Some projects require very little maintenance while others are susceptible to damage and needed repairs.  Some regard for the expected life of a product should be specified along with the range of expected maintenance over the life of the product.  This may be a challenge for more sophisticated designs as the product may still be under development but some mention of maintenance costs is needed in order to evaluate the expected net savings in actual usage.

    5)Supplemental savings potential.  Some products have desirable secondary savings opportunities.  As an example, an externally mounted device that preferentially passes visible light while blocking infrared light in summer would reduce a/c load.  In addition, because the room is bright from the admittance of visible light, more savings can occur through the reduction of artificial lighting while the sun is shining.

    6)Obsolescence.  Some projects may become obsolete with time.  This might mean a savings project becomes stuck in the dreaded category of 'no longer supported'.  A project without such obsolescence would have an advantage.  Similarly, some projects are designed to be easily removable and require no touchup.  In a world of change, this can be a virtue in case a new owner prefers something else.