Heating HW Overnight - Immersion v Heating Oil
Discussion
I'm in the process of moving my electricity supply to Octopus energy as I'll definitely save money on their agile tariff where prices are very low during the night (good for charging EV, dishwasher, washing etc)....sometimes you even get paid to use electricity when there is excess in the system!
Currently during the summer we have the oil fired boiler come on for an hour in the morning/evening to heat the hot water tank up. I'm just wondering roughly at what £/KwH is it cheaper to do it via electricity? It might work out cheaper to set the immersion to come on for an hour at 4am rather than be burning oil? ANyone know how i can work this out?
Btw if anyone is thinking about moving to Octopus let me know and i can share a referral code which gets us both £50 ;-)
Currently during the summer we have the oil fired boiler come on for an hour in the morning/evening to heat the hot water tank up. I'm just wondering roughly at what £/KwH is it cheaper to do it via electricity? It might work out cheaper to set the immersion to come on for an hour at 4am rather than be burning oil? ANyone know how i can work this out?
Btw if anyone is thinking about moving to Octopus let me know and i can share a referral code which gets us both £50 ;-)
I have an oil fired boiler (ancient) and a flow meter on the oil feed pipe - it worked out to be about half the price to just time the immersion to come on.
The heating comes on later, and so I as using oil to heat the entire boiler and water jacket, pipework etc, before it even started to warm the water.
Umless you are on an oil combi, I would think yours will be the same - particularly if you have a modern, foam covered cylinder and not an old bare one with a fibreglass sleeping bad on it.
The heating comes on later, and so I as using oil to heat the entire boiler and water jacket, pipework etc, before it even started to warm the water.
Umless you are on an oil combi, I would think yours will be the same - particularly if you have a modern, foam covered cylinder and not an old bare one with a fibreglass sleeping bad on it.
Heating oil is approximately 10kw per litre. And an boiler is 80-90% efficient, so you can work out from the oil price how much your hot water costs Vs electric.
At the moment oil is cheap as chips at 20p a litre, so electric is probably more expensive. Once oil is back to 50+p a litre you'll need to do some maths...
At the moment oil is cheap as chips at 20p a litre, so electric is probably more expensive. Once oil is back to 50+p a litre you'll need to do some maths...
The only way you'll beat oil with electric (even at 50p a litre) is if you're using solar...
Our summer oil usage for hot water is negligible - the tank level goes down by a few mm.
We have a stainless cylinder and the 'recharge' time has probably halved compared to the copper one it replaced.
The other thing to mention is that using the immersion heater will make water coming out of the top of the tank stupidly hot compared to the rest where as using a boiler to heat via the coil inside is what they are really designed for.
Our summer oil usage for hot water is negligible - the tank level goes down by a few mm.
We have a stainless cylinder and the 'recharge' time has probably halved compared to the copper one it replaced.
The other thing to mention is that using the immersion heater will make water coming out of the top of the tank stupidly hot compared to the rest where as using a boiler to heat via the coil inside is what they are really designed for.
Bill said:
Heating oil is approximately 10kw per litre. And an boiler is 80-90% efficient, so you can work out from the oil price how much your hot water costs Vs electric.
At the moment oil is cheap as chips at 20p a litre, so electric is probably more expensive. Once oil is back to 50+p a litre you'll need to do some maths...
There a lot of variables there - old non-condensing boilers with a good bit of use behind them struggle to reach 70%. 55% on a proper oldie that hasn't had the nozzle replaced for about ten yearsAnd is the system already warm or hot when the water needs heated? At the moment oil is cheap as chips at 20p a litre, so electric is probably more expensive. Once oil is back to 50+p a litre you'll need to do some maths...
An oil boiler has a lot more to heat up than even a modern oil condenser, let alone the fact that it could well be running through poorly insulated pipes. The immersion works out way cheaper for me, half an hour at 3kw is plenty for a long shower or a bath - but he might have a bigger tank, etc.
I put a flow meter on my oil line just to see when I would need the tank filled, but it's been very useful for checking out other things as well. Like turning off all the rads but one, and that can show you that you need to lift the boards and insulate the pipework better.
I think it cost me the grand sum of £30 to buy, and it beats the hole off trekking up the garden to see what level the tank is at.
One thing I would mention, but probably depends on the age of the boiler. I bet if you speak to a plumber, they get a lot of call out in October for boilers not working because they haven't been used for 6 months. Some things just don't like sitting around not being used, a bit like cars.
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