Feature Article

Measuring Energy Use in Buildings: Do Our Metrics Really Add Up?

How much energy our buildings use matters a great deal, but figuring out how to measure that use and compare it from building to building is tricky. Here's a guide to key metrics and how to use them.

Baseline energy use intensity for the Power House in St. Louis, a 1928 building adapted by Cannon Design for its regional office, was 182 kBtu/ft2, while modeled design projected 139 kBtu/ft2. Actual energy use in the building’s first year of operation exceeded expectations at 91 kBtu/ft2.

Photo: Cannon Design and James Steinkamp Photography

Test your energy personality! How much energy our buildings use matters to you, but comparing from building to building is tricky. Answer these questions and we’ll tell you which energy metric suits you best.

1) Which statement describes what you want in a metric?

A. I want to be able to check my utility meter and my solar panel output and call it a day.

B. A lot of the impact of energy use happens before the energy reaches the building. We have to factor that in, even if it takes some work.

C. What’s a kBtu, an MMBtu, or a joule?! I understand dollars.

D. Energy use is so complex. We have to throw some stuff in the blender and come up with a rating or index.

2) Fill in the blank. It’s all about __________.

A. the building.

B. the total energy supply system.

C. the economy, stupid.

D. keeping up with the Joneses.

3) I don’t like metrics that __________.

A. try to do too much.

B. are biased towards certain energy sources.

C. an engineer has to explain to me.

D. don’t level the playing field for all buildings.

If you picked mostly A’s, you probably favor a site energy metric, B’s mean you favor a source energy metric, C’s mean you want to look at energy cost, and D’s mean that you like the idea of a composite building energy rating.

Thanks for playing! While we wrote this quiz for fun, there is a serious point to make. There are many ways to measure energy use; so far we have scratched the surface of four general categories. Each has its pros and cons, so it’s difficult to pick one as being more useful across the board.

With both greenhouse gas emissions and the cost of energy escalating, there is more focus than ever on understanding just how much energy our buildings use, and then figuring out how to use less. In this article we’ll review the key ideas around measuring energy use, and then look at major programs for both homes and commercial buildings that provide deeper analysis.

Published April 29, 2011 Permalink