In 1984 the house had a simple electric immersion heater tank in the workshop but I replaced it with a Quantum heat pump with evaporator panels on the roof around 1998 and it gave good service with a reduced consumption of electricity. The roof panels were barely visible from anywhere and functioned from ambient air temperature rather than solar gain.
It also gave up around 2013 after 29 years of service (15 years were normal life for similar tanks) and I replaced it with another Quantum which required no external roof panels. It was a more compact model, having an exhaust of cool air into the workshop interior which is an advantage in summer whenever I work in there. In winter it is usually too cold anyway and I am more often busy on the computer anyway.
I have placed a time clock on the input power to regulate its consumption of electricity to the daytime when the sun is providing the necessary power. This has reduced its consumption still further and we are still getting adequate hot water.
A timer on the power outlet restricts the heating to sunlight hours to maximise our use of solar power. The insulating foam covers the hot water outlet from the tank to reduce heat loss. It was intended to put a diverting duct from the exhaust through the wall to the exterior to reduce the cooling of the workshop in winter. It will help to cool the workshop in summer so that I can work on my sculptures more comfortably. Will be done shortly. (hopefully – if I ever get this Portfolio finished)