PV Solar - Water Heating

Legacy_user

http://www.yougen.co.uk/blog-entry/2517/Should+I+divert+excess+solar+energy+into+my+hot+water+cylinder'3F/?utm_medium=email&utm_campaign=Consumer+Newsletter+January+2015&utm_content=Consumer+Newsletter+January+2015+Version+B+CID_c4f95b2d8f58cdca7e001116d250ed18&utm_source=Envirosend&utm_term=this%20new%20blog

Discuss. I am using some of my 'spare' PV to top up my EV.

1961Nick

Chris: I have to add a very important caveat here: you’ll only be saving 10p from avoided imports if you currently heat your water with an electric immersion heater. If you currently use gas, you’ll be buying gas at about 5p/kWh giving you no financial savings at all! So I’d say it’s only worthwhile for places that already have electric immersion heaters, and maybe oil boilers. But if you’re on gas, you absolutely shouldn’t get an electric immersion heater put in – it won’t make sense in cost terms, even if you produce the electricity yourself.

This would be true if exports were metered but in almost all cases it's deemed. There has to be a cost saving using surplus electricity that you're not getting paid for anyway!

The cost of gas at 5p/kWh may be higher by the time that energy makes it through several meters of copper pipe (usually unlagged) to the cylinder. Not so bad in winter when the heating is running because diverter valves are often near the cylinder & any energy lost contributes to heating. In summer, which is when these systems mainly work, pipework losses are unwanted & add to the cost of DHW.

Just a thought.