I’m a single person household. So I found out years ago I could save $20 per month, by only having the hot water cylinder on for 1 hour per day. This is not enough to heat the entire cylinder to the thermostat temperature, but say only half. Of course hot water rises from the bottom to the top where the outlet is, and the temperature is hot enough to shower with, wash hands etc (adjust the shower rose as they premix cold). The dishwasher and washing machine only use cold which they heat to the required temp, and the cylinder is thus not diminished. And if I use some hot water from the tap, the cylinder fills cold to the bottom where it stays as a cold layer, and without the heater on it doesn’t mix with the existing water. This would only work with one to two persons households , who can discipline themselves to turn the cylinder on and off every evening (sometimes you need longer if ripple control is used in winter). Ideally a timer, would be best to turn at say at 3 to 4am for a hour so its hottest for morning. But I don’t think domestic timers can handle the 3kW heaters, and need an electrician to install the timer.
13
Jul