Residential Demand Module - NEMS Documentation
July 2025
Introduction
Purpose of this report
This report documents the objectives, analytical approach, and structure of the National Energy Modeling System (NEMS) Residential Demand Module (RDM). The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, and Fortran source code.
This document serves three purposes. First, this report meets the legal requirement for the U.S. Energy Information Administration (EIA) to provide adequate documentation in support of its reports, according to Public Law 93-275, Section 57(b)(1). Second, it is a reference document with detailed descriptions of our modeling for energy analysts, other users, and the public. Finally, it facilitates continuity in model development by providing documentation from which energy analysts can undertake model enhancements, data updates, model performance evaluations, and parameter refinements..
Model summary
The NEMS Residential Demand Module is used to develop long-term projections and energy policy analysis during the time horizon beginning with our most recent Residential Energy Consumption Survey (RECS) (the module’s base year, or RECSyear) through 2050 (the current projection horizon). The model generates projections of energy demand—or energy consumption; the terms are used interchangeably throughout the document—for the residential sector by end-use service, fuel type, and U.S. census division.
The RDM uses inputs from NEMS, such as energy prices and macroeconomic indicators, to generate energy consumption by fuel type and census division in the residential sector. NEMS uses these projections to compute equilibrium energy prices and quantities.
The RDM is an analytic tool we use to address current and proposed legislation, private sector initiatives, and technological developments that affect the residential sector. Examples of policy analyses include assessing the potential impacts of:
- New end-use technologies
- Changes in fuel prices due to tax policies
- Changes in equipment energy-efficiency standards and building energy codes
- Financial incentives for energy efficiency and distributed generation investments
Documentation
U.S. Energy Information Administration, Residential Demand Module of the National Energy Modeling System: Model Documentation, DOE/EIA-M067 (2025) (Washington, DC, August 2025).
Model archival citation
The module, as part of the NEMS system, has been archived for the Reference case published in the Annual Energy Outlook 2025 (AEO2025), DOE/EIA-0383 (2025).
The latest open-source NEMS code and input files are available at https://github.com/EIAgov/NEMS.
Model contact
Buildings Energy Consumption and Efficiency Modeling
EIAInfoConsumption&EfficiencyOutlooks@eia.gov
Report organization
Chapter 1 of this report discusses the purpose of the RDM and gives specific details on the objectives, primary inputs and outputs, and relationship of the module to other modules in NEMS.
Chapter 2 describes the rationale behind the design, fundamental assumptions regarding consumer behavior, and alternative modeling approaches.
Chapter 3 describes the NEMS RDM structure, including flowcharts and major subroutines.
Appendixes to this report document representative variables and equations contained in the Fortran source code. Appendix A catalogues the input data used to generate projections in list and cross-tabular formats. Appendix B provides mathematical equations that support the program source code in the module. Appendix C is a bibliography of reference materials used in the development process. Appendix D discusses the data quality of the primary data source that informs the module.