To help meet Building America's goal to develop market-ready energy solutions that improve efficiency of new and existing homes, the National Renewable Energy Laboratory (NREL) developed the Building Energy Optimization (BEopt) software tool. This specialized computer program is designed to identify optimally efficient designs for new and existing homes at the lowest possible cost.

BEopt produces detailed simulation-based analysis and design optimization based on specific house characteristics, such as size, architecture, occupancy, vintage, location, and utility rates. BEopt can help researchers and energy analysts identify the most cost-effective combinations of efficiency strategies for whole-house energy savings. These savings are calculated relative to a reference building that is either user-defined or an automatically generated Building America Benchmark home. See the House Simulation Protocol report to learn more about the Building America Benchmark home.

Collage of images taken from various BEopt output screens. The top, left image lists building measures and design elements with a base point, current point, and available options for that measure. The top, right image shows a colorful wave spectrum and ha

BEopt input/output includes multiple modes and level of detail.

BEopt 2.4 Now Available!
With the release of BEopt Version 2.4 Beta, users can now perform modeling analysis on multifamily buildings! Other new options for input include: heat pump clothes dryers; electric/gas clothes dryers; condensing tank water heaters; door construction and area; window areas defined by façade-specific WWRs; and 2013 ASHRAE 62.2 mechanical ventilation. Read about the new features and visit the BEopt website to download. View a series of webinars that explain the new features.

A new report, Using the BEopt Automated Residential Simulation Test Suite (BARTS) to Enable Comparative Analysis Between Energy Simulation Engines, describes a study that uses BARTS to facilitate comparison of two energy simulation engines across various building components and includes building models that isolate the impacts of specific components on annual energy consumption.

Benefits of Building Optimization

Building optimization helps to identify designs that minimize total cost of ownership while maximizing energy savings. When building optimization is performed before construction or retrofit begins, the components can be designed concurrently, leading to a more integrated, whole-building approach. Efficiently designed buildings reduce energy use and costs while increasing comfort and quality for the building occupants.

BEopt's sequential search technique provides realistic construction options and design alternatives that represent currently available products and construction techniques. The search optimization technique:

Sample BEopt graph displays vertical bar graph with Mortgage and Utility costs in $/year from $0-$2,500 on the vertical axis. The horizontal axis displays energy savings in % from 0-100. There's a curved line representing cash flow with four points along

Conceptual plot of the least cost path for high-performance homes.

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

Updates on the BEopt Software

BEopt Version 2.3 is now available! Visit the BEopt website to learn more about BEopt 2.3 and to sign up to receive updates about the BEopt software. For more on home efficiency measures and to access a database of measures that can be used in analysis software, including BEopt, see Efficiency Measures and Costs.