Wednesday, August 26, 2009

ASHRAE Handbook Tables Not to be used as Default Numbers


“It has come to our attention that some code jurisdictions are utilizing fenestration U-factor and SHGC ratings from tables found in the ASHRAE Handbook of Fundamentals. Please know that the ASHRAE Handbook subcommittee developed these tables for preliminary design guidance only and are not to be used as default numbers in the code.

ASHRAE, IECC, and most state codes already have punitive default tables for fenestration products lacking the required energy ratings. Using these as default numbers can dramatically overstate the performance of the windows and curtain walls installed on buildings. Code officials and other energy experts should look for NFRC ratings on these products to be sure that the U-factors and SHGC ratings are credible.”

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