As I wrote in a previous post about looking for wasted energy around the home “Fuel Included isn’t just about electric cars, but about the transition to a low carbon lifestyle”. Having insulated our hot water tank the next logical step seemed to be to power it from our renewable electricity supply so as to save the carbon footprint of heating it with gas.

Of course, electricity is more expensive than gas per unit so I looked for a way to power it cheaply. This can be done during the day from solar, and also at night on an Economy 7 tariff. Therefore I needed a timer controller that would switch on the electric immersion heater only during the Economy 7 hours and, later in the year when there’s significant sunshine, during peak solar hours.

To make a fairly short story even shorter, I wired in a small timer and it was a relatively easy job (though I wouldn’t recommend it if you have no electrical experience or knowledge). We had had some problems with the immersion heater (audible bubbling, etc.) that indicated that the thermostat needed replacing so I simply bought a new thermostat and picked up the timer at the same time. They were from a local Screwfix outlet, but obviously there are lots of other suppliers available.

The one I got was an LAP Digital Weekly Immersion Timer and it seems to get the job done at a reasonable price. I switched off the electrics, cut the cable from the immersion switch to the immersion element and fitted the timer; the instructions that came with it were basic but sufficient.

I installed the new thermostat at the same time and adjusted its set temperature to be higher than the gas one (which is on the front of the tank) so that it can act as a ‘pre-heater’ and do the bulk of the water heating overall. Combined with installing the new insulated jacket previously described I’m expecting to see a significant reduction in our gas bill from now on.