What's a good way to forecast demand for residential solar panels?

Start with a combo of bottom-up demand drivers — electricity rates, incentives like the ITC, and local permitting data — then layer in demographic filters like homeownership rates and median income. Tools like Wood Mackenzie or NREL's market reports are solid baselines if you don't want to build from scratch. Also check Google's Project Sunroof data for regional solar potential, it's surprisingly useful for calibrating adoption curves.