BEopt: Building Energy Optimization Tool

The BEopt™ (Building Energy Optimization Tool) software provides capabilities to evaluate residential building designs and identify cost-optimal efficiency packages at various levels of whole-house energy savings along the path to zero net energy.

BEopt can be used to analyze both new construction and existing home retrofits, as well as single-family detached and multi-family buildings, through evaluation of single building designs, parametric sweeps, and cost-based optimizations.

BEopt provides detailed simulation-based analysis based on specific house characteristics, such as size, architecture, occupancy, vintage, location, and utility rates. Discrete envelope and equipment options, reflecting realistic construction materials and practices, are evaluated.

BEopt uses EnergyPlus, the Department of Energy's flagship simulation engine. Simulation assumptions are based on ANSI/RESNET/ICC Standards and the Building America Housing Simulation Protocols.

The sequential search optimization technique used by BEopt:

  • Finds minimum-cost building designs at different target energy-savings levels
  • Identifies multiple near-optimal designs along the path, allowing for equivalent solutions based on builder or contractor preference.


A BEopt Version 3.0.1 Beta release (Mar. 16, 2023) is now available. Download the BEopt 3.0.1 Beta setup file. It incorporates significant new capabilities including:

  • Updates to EnergyPlus v22.2
  • OpenStudio-HPXML for energy modeling
  • Runtime speed improvements
  • Simplified inputs in some categories (particularly HVAC equipment and water heaters)
  • Hourly electricity CO2e emissions factors
  • New scheduling and stochastic occupancy modeling capabilities
  • Updated rating metrics (e.g., SEER2 and HSPF2 for HVAC, UEF for water heaters, etc.)
  • The ability to model Li-ion battery storage for homes with PV
  • Additional heat pump and heat pump water heater inputs/capabilities
  • Additional output capabilities (heating/cooling component loads, HVAC design loads, subhourly time series data, etc.)
  • The switch from modeling entire multifamily buildings to individual dwelling units
  • Updated source energy factors, utility rates, and CO2e emission factors
  • A bug fix for possible crash during optimization
  • A bug fix for downloading EPW weather files
  • A bug fix for foundation heat transfer errors/abnormalities
  • A bug fix for error when creating new options in some categories
  • A deprecation of some capabilities of low value or high maintenance.

See the release notes for a detailed list of changes.

Older versions of BEopt are still available.

Download the BEopt 2.8 setup file (Jan. 4, 2018).

Download the BEopt 2.7 setup file (Nov. 7, 2016).

At this time, BEopt is available only for Windows. Mac users have successfully used BEopt through a virtual machine or by using a Windows workstation on the cloud.


Unmet Hours is an externally hosted forum that serves as a question-and-answer website for the building energy modeling community.

When posting a new question, consider adding the "beopt" tag to your post.


DView is provided with BEopt for visualizing time series (e.g., hourly or subhourly) simulation output. It is also available as a stand-alone application for visual analysis of other types of time series data. DView opens CSV files and recognizes several weather data file formats, including TMY2, TMY3, and EPW files.

The stand-alone application can be downloaded in the following versions:

DView 1.2 Windows

DView 1.0 Darwin

DView 1.0 Windows

Additional information can be found on the DView wiki.


Heating and Cooling Energy Modeling of 3D-Printed Concrete Construction of Residential Buildings (2022)

Demand Response Analysis for Different Residential Personas in a Comfort-Driven Behavioral Context, Proceedings of the ASME 2021 International Mechanical Engineering Congress and Exposition (2021)

Are Ducted Mini-Splits Worth It?, ASHRAE Journal (2018)

Energy Efficiency Potential in the U.S. Single-Family Housing Stock, NREL Technical Report (2017)

Zero Energy Ready Home Multifamily Case Study Analysis, NREL Technical Report (2016)

Public Housing: A Tailored Approach to Energy Retrofits, NREL Technical Report (2016)

Using BEopt (EnergyPlus) With Energy Audits and Surveys To Predict Actual Residential Energy UsageScience Direct (2015)

Kaupuni Village: A closer look at the first net-zero energy affordable housing community in Hawai‘i, NREL Technical Report (2012)

Design and Evaluation of a Net Zero Energy Low-Income Residential Housing Development in Lafayette, Colorado, NREL Technical Report (2012)

A Method for Determining Optimal Residential Energy Efficiency Retrofit Packages, NREL Technical Report (2011)

Ducts in the Attic? What Were They Thinking?, NREL Technical Report (2010)

Preliminary Assessment of the Energy-Saving Potential of Electrochromic Windows in Residential Buildings, NREL Technical Report (2009)

Searching for the Optimal Mix of Solar and Efficiency in Zero Net Energy Buildings, NREL Technical Report (2008)

Habitat for Humanity Zero Energy Home: A Cold-Climate Case Study for Affordable Zero Energy Homes, NREL Technical Report (2008)

Defining a Technology Pathway Leading to New Homes with Zero Peak Cooling Demand, NREL Technical Report (2006)

Analysis of Residential System Strategies Targeting Least-Cost Solutions Leading to Net Zero Energy Homes, NREL Technical Report (2006)

Optimal Building Designs on the Path to Zero Net Energy, NREL Technical Report (2004)


Scott Horowitz

Senior Research Engineer

BEopt has been developed by NREL in support of the U. S. Department of Energy Building America Program goal to develop market-ready energy solutions for new and existing homes.