HOMER Legacy is a free computer model that simplifies the task of evaluating design options for both off-grid and grid-connected power systems for remote, stand-alone, and distributed generation (DG) applications.
As of April 14, 2015, HOMER Legacy is available only for the following uses:
1 - Academics and students working on teaching and research, or on energy access projects.
2 - Non-profit organizations working on energy access.
Absolutely no free support is available for HOMER Legacy users, including issues with installation.

HOMER's optimization and sensitivity analysis algorithms allow the user to evaluate the economic and technical feasibility of a large number of technology options and to account for uncertainty in technology costs, energy resource availability, and other variables.

The Center for Energy Efficiency and Renewable Energy (CEERE) provides technological and economic solutions to environmental problems resulting from energy production, industrial, manufacturing, and commercial activities, and land use practices.

Legacy free version is still available free for educational and academic activities after registration on the HomerEnergy website and the completion of a specific form.
"If Licensee has downloaded the free HOMER Legacy software (HOMER 2.68), use is restricted to either non-commercial educational purposes or non-commercial applications supporting energy access by a non-profit organization (delivery of energy for essential services in developing countries). Identification of these uses is in Licensor’s sole discretion. In addition, Licensee agrees to provide information on how such Software will be used prior to downloading, installing, or using the Software, and upon License renewal to provide information on how the Software was used."

Homer solar software
This program is also available in a pro version to purchase "HOMER 2" with new features and updates : More information about HOMER 2