Traditionally, photovoltaic (PV) and solar hot water (SHW) technologies have been designed with separate design tools, making it difficult to determine the appropriate mix of PV and SHW. A new tool developed at the National Renewable Energy Laboratory changes how the analysis is conducted through an integrated approach based on the life cycle cost effectiveness of each system. With 10 inputs, a person with only basic knowledge of the building can simulate energy production from PV and SHW, and predict the optimal size of each system. The user can also select from 5 optimization criteria: Greenhouse Gas Reduction, Net-Present Value, Renewable Energy Production, Levelized Cost of Energy, and Discounted Payback Period. SolOpt provides unique analysis capabilities not currently available in any other software programs. The optimization procedure and tool comparison study results with industry accepted tools for both SHW and PV are presented.