Best way to segment customers for a new home solar product?

For residential solar, I'd start with a combination of geographic/demographic cuts (homeowners, 35+, HHI $75k+, sunbelt or high-utility-cost regions) layered with attitudinal segments around financial motivation vs. environmental motivation — those two groups respond very differently to messaging. A quick conjoint or even a simple cluster analysis on a 300-400 person survey can get you there fast. The 'financial saver' segment almost always converts better early on, so I'd prioritize them first.