Software screen captures and equations


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.

Modelica Buildings Library

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

Version Download Supported? Website
Yes Modelica Buildings Library


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. 

Version Download Supported? Website
Yes Optics


A simplified PC-based tool, based on extensive DOE-2 simulations. Readily useable by builders, architects, or lenders to provide reliable estimates of building energy consumption. PEAR is also useful as a tool for producing home energy ratings.

Version Download Supported? Website


ProForm is a software tool designed to support a basic assessment of the environmental and financial impacts of renewable energy and energy efficiency projects. Given the necessary data, ProForm calculates basic financial indicators and avoided emissions of CO2 and local air pollutants expected from a project.

Version Download Supported? Website
No ProForm


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.

Version Download Supported? Website


A simulation-based tool developed to allow the DOE Institutional Conservation Program (ICP) staff and participants to reliably determine the energy savings directly attributable to ICP-supported retrofit measures implemented in a building. RESEM (Retrofit Energy Savings Estimation Model) calculates long-term energy savings directly from actual utility data, with corrections for weather and use variations between the pre-retrofit and post-retrofit utility data collection periods.

Version Download Supported? Website


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.

Version Download Supported? Website

Simulation Problem Analysis and Research Kernel (SPARK)

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

Version Download Supported? Website


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.

Version Download Supported? Website
6.3 Yes THERM


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.

Version Download Supported? Website
6.3 Yes Window