Frequently Asked Questions

Where does the data come from?

In conjunction with the Pacific Northwest National Laboratory (PNNL), we've developed these numbers using the Advanced Energy Retrofit Guide (AERG). The AERG was developed by PNNL in 2011 to provide general project planning guidance as well as financial payback metrics for common energy efficiency measures. We have updated the energy and cost estimations of the AERG to current market values.

Are these numbers based on measured data from buildings or calculated data?

The energy savings calculations are based on a model 200,000 square foot building, using Open Studio and Energy Plus programs, which are both Department of Energy supported building energy modeling tools. Cost modeling is based on the real world costs of the upgrades. Though initial cost estimates are from 2011, we performed a sensitivity analysis to see which technologies have had a significant drop in price, and adjusted the model accordingly (for instance, with LED lighting retrofits). The AERG presents case-studies of its retrofit packages that illustrate the savings potential in real buildings across the country.

Note that values presented in this tool may not sum due to rounding.

How were the size ranges selected?

The energy and financial benefits are scaled linearly from the representative AERG building to the sizes presented in the tool. We recognize that smaller buildings may not have the same opportunities for retrofit or commissioning that large buildings do, so we've curated the list of upgrades at the smaller building sizes to items that may be applicable. We selected 5,000 square feet as the minimum building size because it corresponds to the minimum square footage required for reporting EnergyStar scores and complying with the Guiding Principles for Federal and High-Performance Sustainable Buildings.

Where does the map come from?

The climate zone map is from the Building America, definition of climate zones, which is also the map used by Commercial Building Energy Consumption Survey (CBECS) 2012. Building America is a research program run by the Department of Energy that focuses on bringing cutting-edge innovations and resources to the market. Descriptions of the climate zones are available here: http://energy.gov/eere/buildings/climate-zones.

No data is available for northern Alaska since the AERG did not include the subarctic climate zone.

Does the AERG use the same definitions?

The AERG uses data from 5 representative climates and markets across the country. These five cities are in distinct Building America climate zones, and are the basis for the variation in cost-effectiveness based on location.

What about residential?

The estimates here are for office buildings, but many may still apply to residential and industrial buildings. Use these numbers as a starting point for investigating which upgrades may apply to your building.

Can I use these numbers in planning building upgrades?

Actual savings will depend on a variety of factors including actual operating conditions. The data presented here can be used as a first step toward determining what upgrades may be applicable to your building, but any decisions should first be thoroughly investigated by a building engineer or other certified professional.