Thanks for the info. We have just moved into a new home. The hot water is hot during sunny periods, but is only warm at night and during cloud. The tank is on the roof, I don't think the heating element is heating sufficiently during cloudy weather or at night. I can't see any switches, only the main meter box, which has three smart meters. I don't have access to the system on the roof, as it is a two storey house. In our previous house, with gas hot water, we could adjust the heat at the tank.