I'm curious if these systems form a net positive. The cost of a thing provides a pretty reasonable proxy as a summation of the energy put into it's creation. The implication being that a balcony solar system is probably roughly net-negative, environmentally speaking, until it reaches its ROI.

I wonder if enough of these systems reach return to cover all the ones that don't for some reason or another. Looks like ROI might be 3-7 years, at the high end seems probable people would maybe move and not be able to use them and never really get their money's worth out of it.