We have few interior rooms on our project that “borrow” daylight through relites facing exterior window. Can we include these rooms in our calculations? If yes, is there a way to pursue this using option 2 (prescriptive)?

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TODD REED

Energy Program Specialist

PA DMVA

LEEDuser Expert

626 thumbs up

Thu, 08/18/2011 - 13:10

I'm going to say no. However, previous CIRs that state borrowed light is not accepted has not been validated for 2009 projects. I would not argue that case to a reviewer. Since the prescriptive method is a formula which is only attended for one layer of glazing, then borrowed light would not work. Even if you were to do a weighted average of the two glazings, the formula does not consider the effects of reflection and refraction of light as it travels through the layers of glass.

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FAQs about IEQc8.1 :

"Borrowed Light" For Interior Rooms

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