ASHRAE standard aims for consistency in measuring building energy use

The newly revised ANSI/ASHRAE Standard 105-2014, Standard Methods of Determining, Expressing, and Comparing Building Energy Performance and Greenhouse Gas Emissions, is intended to provide consistency in reporting the energy performance of existing or proposed buildings.

The standard answers such questions as: Should the measurements of a building’s area used in the equation to derive energy use per square foot be taken from the exterior dimensions or to the centerline of the wall? And, should storage spaces be included even though they are unoccupied?

“A standard method of measurement is needed to compare one building’s energy use to another,” says Keith Emerson chair of the Standard 105 committee. “For instance, comparing one building’s summer energy use to another building's winter use would be comparing apples and oranges.”

The standard provides a common basis for reporting building energy use in delivered energy forms and expressions of energy performance, and for comparing energy performance in terms of energy resources used and greenhouse gas emissions created—both across buildings and for energy efficiency measures within buildings. It also provides guidelines for comparing design options.

“To keep the standard flexible, a number of decisions are left to those who adopt it, including what should be calculated beyond site energy and the multipliers for those additional calculations,” Emerson said.

(https://www.ashrae.org/news/2014/revised-ashrae-standard-helps-to-compare-building-energy-performance)