Consistency is key.
The how-to of measuring a building’s energy use can get convoluted. Are the measurements of a building’s area taken from the exterior dimensions or to the centerline of the wall? Are storage spaces included or not?
The newly revised ANSI/ASHRAE Standard 105-2014, Standard Methods of Determining, Expressing, and Comparing Building Energy Performance and Greenhouse Gas Emissions, supports commonality in reporting building energy performance to provide consistent methods of measuring, expressing, and comparing.
“A standard method of measurement is needed in order to be able to compare one building’s energy use to another,” says Keith Emerson, chair of the committee that wrote the standard. “For instance, comparing one building’s summer energy use to another building’s winter use would be comparing apples and oranges.”
The new standard now includes procedures for going beyond site energy to calculate the impact of building energy use on primary (source) energy and greenhouse gases.
It also provides a common basis for reporting energy use in terms of delivered energy forms and expressions of performance, relating design options, and comparing energy performance in terms of energy resources used and greenhouse gas emissions created.