Can someone provide some clarification on the statement
"component of part or parts of a nonsolar energy system"

For instance, if I have a Solar Thermal (Hot Water) system which provides hot water and may provide assist to the home heating AND I have a boiler which provides "backup" hot water for hot and heating, is the entire system, including the boiler eligible or is the boiler "part of a non-solar energy system"

How this description is sufficient. Pls ask me further questions if description is not sufficient.

Thanks
Steve