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Does the ENERGY STAR score account for building age? Follow

No. The ENERGY STAR score does not factor in building age. There are no specific numeric adjustments in the ENERGY STAR score that give you a credit or a penalty based on your building age.

Age does not necessarily make a building more or less energy efficient. Some changes over time may serve to lower building energy use, while others could actually contribute to higher energy consumption. More on the relationship between age and energy.

In fact, when EPA assessed some of our models we found that an additional variable for “year built” was not statistically significant. For example, if we add this variable to our Office model the “p-level” is 0.4118. But, you need the p-value to be less than 0.1 for a variable to be statistically significant with 90% confidence. So, when we take into account other factors like climate, hours, workers, and computers, building age does not have a measurable effect on office energy consumption. 

However, regardless statistical significance, EPA would not incorporate a variable like age in our regression analysis an ENERGY STAR score. There are two main reasons why age theoretically might affect energy:

  • Changes in business practices like hours of operation or worker density – In this case we would not incorporate age, because we already include the operational items that are changing like hours and worker density.
  • Changes in technology and building materials – In this case we would not incorporate age, because we do not want to normalize for technology.  Our regression models never include technology in the normalization – rather, technology affects the score only to the extent it lowers the actual bills.  More on what we do/do not include the score.

Therefore, EPA has determined the adjustments specifically for age are not appropriate in the context of the ENERGY STAR score.  To learn more you may want to review our technical reference on the ENERGY STAR score.

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