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.
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