ResStock Analysis Tool

The ResStock™ analysis tool is helping states, municipalities, utilities, and manufacturers identify which home improvements save the most energy and money.

Photo of a four researchers in front of a wall of screens, showing different maps and charts.


Across the country, there's a vast diversity in the age, size, construction practices, installed equipment, appliances, and resident behavior of the housing stock, not to mention the range of climates. These variations have hindered the accuracy of predicting savings for existing homes.

With support from the U.S. Department of Energy (DOE), NREL developed ResStock. It's a versatile tool that takes a new approach to large-scale residential energy analysis by combining:

  • Large public and private data sources
  • Statistical sampling
  • Detailed subhourly building simulations
  • High-performance computing.

This combination achieves unprecedented granularity and, most importantly, accuracy in modeling the diversity of the housing stock and the distributional impacts of building technologies in different communities.

ResStock leverages DOE's open-source building energy modeling ecosystem of OpenStudio® and EnergyPlus™. With NREL supercomputing, the ResStock team has run more than 20 million simulations using a statistical model of housing stock characteristics. This data has helped researchers uncover $49 billion in potential annual utility bill savings through cost-effective energy efficiency improvements.

Detailed information on the technical and economic potential of residential energy efficiency improvements and packages is available for 48 states domestically. Policymakers, program designers, and manufacturers can use these results to identify improvements with the highest potential for cost-effective savings in a particular state or region as well as identify customer segments for targeted marketing and deployment.

Publicly available ResStock analysis results—including the U.S. Building Stock Characterization Study and the End-Use Load Profiles dataset—are used by a broad set of analysts representing hundreds of cities, states, utilities, manufacturers, and other organizations to make decisions related to building decarbonization.


ResStock analysis can be used to answer questions for a variety of applications.

Cities and States

  • How much energy can be saved through home improvements that are cost-effective?
  • How can buildings contribute to city/state energy or emissions targets?


  • How does market size for my technology vary regionally?
  • How should my company prioritize R&D investments?

Utility Companies and Programs

  • How can energy efficiency  improvements be targeted for specific customer segments to improve cost-effectiveness?
  • Which energy efficiency measures and distributed energy resources are best for relieving grid congestion?
  • What segments of the housing stock can provide the most load flexibility? 

ResStock has also been used to develop an application programming interface that generates a conservative Energy Cost Estimate based on high-level inputs available from data sources similar to Fannie Mae Form 1004 (See Appendix D in RMI's Build Back Better Homes).

Real Estate Industry 

  • What are the estimated energy costs of a home for sale
  • What is the value of making efficiency improvements?

Learn more about ResStock capabilities.


U.S. Building Stock Characterization Study: A National Typology for Decarbonizing U.S. Buildings. Part 1: Residential BuildingsNREL Technical Report (2021)

End-Use Load Profiles for the U.S. Building Stock: Methodology and Results of Model Calibration, Validation, and Uncertainty Quantification, NREL Technical Report (2022)

A full list of ResStock publications can be found on the ResStock website. 


Contact to learn how ResStock can benefit your organization.