Everybody and their dog had a solar heater on their house in Cyprus, from 30 years ago. It was cheap deployable tech accessible to literally peasant farmers.

I visited Sardinia recently for the first time, and saw the exact same type of houses built there, with the same climate, but not a single solar heater on their roofs. I wondered aloud why, but got no answer.

My guess is that an energy company took an interest early on in Sardinia, and Cyprus was thankfully missed for a few decades.