A Closer Look at Our New National Energy Standard: Comparison of the 1999 and 2004 Versions of ASHRAE 90.1

In this post, I noted that ASHRAE Standard 90.1-2004 has been established by the Department of Energy as the commercial building reference standard for state building energy codes starting in 2010. Meanwhile, the stimulus package appears to be encouraging adoption of the latest version, which is 90.1-2007, as noted in this post.

I promised a more in-depth comparison of the 1999 (current national energy standard) and the 2004 (new national energy standard starting December 30, 2010) versions of 90.1 in the earliest post, and you can find it here in a new whitepaper I have written for the Lighting Controls Association, published free on their website. LCA also offers a course on energy codes that includes all post-1989 versions of 90.1 in its Education Express program, available free here.

In a nutshell, the major differences are:

• Change to recognized methods for automatic lighting shutoff and new exceptions.

• Addition of occupancy sensor requirements for classrooms, meeting and lunch rooms.

• New exit sign wattage requirement.

• Complete replacement of interior lighting power density allowances.

• Revised exterior lighting power density allowances.

Craig DiLouie

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