Domestic solar heater in <a href="https://en.wikipedia.org/wiki/Johannesburg" class="extiw" title="en:Johannesburg">Johannesburg</a>, South Africa (about 1500 m above sea level).  This heater supplies hot water for the servant's quarters, typically a single-occupancy flat.
<a href="//commons.wikimedia.org/wiki/User:Martinvl" title="User:Martinvl">Martinvl</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>