Software developed by ETA researchers for energy-efficient buildings, and electricity grid. Download free or for a nominal licensing fee.


ETA scientists develop software to help design more energy-efficient buildings, audit energy use in buildings, examine the economics of sustainable projects, and model components of building systems. Most ETA software and documentation is available for download and public use.

Version Supported? Website

Building Controls Virtual Test Bed

The Building Controls Virtual Test Bed (BCVTB) is a software environment that allows expert users to couple different simulation programs for co-simulation, and to couple simulation programs with actual hardware.

1.1.0 Yes

City Building Energy Saver (CityBES)

CityBES is a web-based data and computing platform, focusing on energy modeling, benchmarking and performance visualization of a city's building stock to support district or city-scale energy efficiency programs. CityBES uses and international open data standard, CityGML, to represent and exchange 3D city models. CityBES employs CBES to simulate building energy use and calculate savings from energy retrofits. CityBES targets urban planners and developers, city energy managers, building owners, utilities, energy consultants and researchers.

1.0 Yes

Commercial Building Energy Saver (CBES)

CBES is a web-based energy retrofit analysis tool for small-to-medium-sized commercial buildings in California. CBES provides energy benchmarking and three levels of retrofit analysis considering the project goal, data availability, and user experience. CBES offers 80 energy conservation measures (ECMs) for lighting, envelope, plug-in equipment, HVAC, and service hot water retrofit upgrades. CBES uses OpenStudio and EnergyPlus to create and run energy models.

1.0 Yes

Demand Response Quick Assessment Tool (DRQAT)

The opportunities for demand reduction and cost saving with building demand responsive control vary tremendously with building type and location. This assessment tool will predict the energy and demand saving, the economic saving, and the thermal comfort impact for various demand responsive strategies. It is based on the most popular feature and capabilities of EnergyPlus. Users of the tool will be asked to enter the basic building information such as types, square footage, building envelope, orientation, utility schedule, etc.

4.0.0 Yes


The Distributed Energy Resources Customer Adoption Model (DER-CAM) is a techno-economic model of customer DER adoption. Users input market information (fuel prices), system load information (hourly enduse loads), and DER technology information (costs, performance data, etc) and DER-CAM outputs the optimal selection of technologies, e.g. PV, solar thermal or CHP that should be adopted and details how they should be operated based on the specified inputs. Other outputs also include CO2 emissions. 



Best features of the DOE-2 and BLAST programs combined into a new, powerful, and more accurate program.



A multi-parameter optimization program designed for minimization of an objective function, such as annual energy use, that is calculated by an external simulation program such as EnergyPlus or DOE-2. 


Home Energy Saver for Consumers

The Home Energy Saver™ (HES) empowers homeowners and renters to save money, live better, and help the earth by reducing energy use in their homes. HES recommends energy-saving upgrades that are appropriate to the home and make sense for the home's climate and local energy prices. The money invested in these upgrades commonly earns "interest" in the form of energy bill savings, at an annual rate of 20% or more.

2.0 Yes

Home Energy Saver for Professionals

The Home Energy Saver™ (HES) pro offers similar residential energy-saving upgrade recommendations for energy auditors, inspectors, and contractors.

2.0 Yes

Modelica Buildings Library

The Modelica Buildings library is a free open-source library with dynamic simulation models for building energy and control systems.


Occupancy Simulator

The Occupancy Simulator is a web application using stochastic models to simulate occupant presence and movement in buildings, and generate detailed occupant schedules at the individual occupant, room, and building levels. The generated schedules capture diversity and stochastic nature of occupant activities. These schedules can be downloaded and used for building simulation.



A computer program to calculate the optical properties of glazing systems and laminates. The program can be used to construct new laminates from existing components and manipulate glazing layers by adding coatings, films, changing the substrate or changing the thickness. Optics includes the International Glazing Database with measured spectral data of more than 1000 different glazings. 

6.0 Yes


A photometrically accurate computer-generated graphic simulation of lighting in indoor environments. The ultra-realistic images produced by the program facilitate the designer's visualization of lighting design options.



Program for calculating the annual heating and cooling energy use and costs due to fenestration systems in residential buildings. RESFEN (RESidential FENestration) also calculates their contribution to peak heating and cooling loads.

6.0 Yes

Simulation Problem Analysis and Research Kernel (SPARK)

An object oriented environment for graphically assembling custom models of complex building energy systems.



A state-of-the-art, Microsoft WindowsTM based computer program for modeling two-dimensional heat-transfer effects in building components such as windows, walls, foundations, roofs, doors and other products where thermal bridges are of concern. THERM's two-dimensional conduction heat-transfer analysis is based on the finite-element method, which can model complicated geometries.

7.6.01 Yes


A window thermal analysis computer program that is the de facto standard used by U.S. manufacturers to characterize product performance. The program has been selected by the newly formed National Fenestration Rating Council as the basis for development of energy rating labels for windows.

7.6.04 Yes