Below is a samle template you can use when dealing with solar installers. The letters provides some structure and guidelines around the important aspects your installer must consider. Thanks to Max VK3YBA for sharing this with QRM guru. It reflect his experience in successfully installing a noise free solar system at his QTH.
DRAFT LETTER FOR USE WHEN REQUESTING AN SYSTEMS QUOTE FROM A ROOFTOP SOLAR PANEL INSTALLATION COMPANY
It is also worth reading the QST article on this topic here