Is it now cheaper to heat a tank with electricity?

[bruncher]

Our Megaflow tank can be heated by gas or electricity. I always used the gas option - until now. Has anyone seen any calculations regarding this? Maybe with the big increase in gas prices, electricity is now cheaper.

If the gas boiler is being used for the central heating, is that a factor in the above question?

[DrFfybes]

It depends...

To heat the tank, the boiler needs to heat up and then heat up the pipes leading to and from the tank. The length of those runs has an impact. It depends if the heating is already on, as much of the run will already be warm.

It depends how cold the tank is, as a colder tank will need more enrgy to heat up than a warmer one, so the initial pipe warming is less of a factor with a cold tank, but if gas is cheaper, you save more.

It depends how efficient your boiler is.

But mostly, it depends on how much you pay per kWh for your gas and leccy. If you're on a fixed rate, it won't matter yet. But a lot of leccy is generated by gas, so both will go up in price.

Do you have a smart meter? You can turn off the CH, turn on the HW, and see how much it costs until the tank is hot and the boiler stops. Then the next day use the immersion.

Paul

[gryffron]

Electricity is still 4x the price of gas (Used to be 5x). But I still doubt your gas boiler could be that inefficient.

Gryff

[88V8]

Our Megaflow tank..

When 'sizing' the boiler, one used to allow 15,000bthu for the hot water.
For a normal house with a normal tank.

So relative to the size of your boiler, that may give you a clue how much it's costing.
But not much of a clue.

V8

[scotview]

Rough costs based on my current tariffs, I think this a reasonably sensible estimate but maybe wrong.
Say 2kW immersion heater takes 30 minutes to heat the tank, so 1kWh used.
1kWh gas at 3.55p/kWh will cost 3.55p to heat the tank.
1kWh electricity at 17.25p/kWh will cost 17.25p to heat the tank.

Even with new tariffs still think gas will be cheaper.

[scotview]

I've redone the cost estimate above based on average capped tariffs post 1st April 2022 (thanks to staffordian for the info).
Say 2kW immersion heater takes 30 minutes to heat the tank, so 1kWh used.
1kWh gas at 7.3 p/kWh will cost 7.3p to heat the tank.
1kWh electricity at 28.0p/kWh will cost 28.0p to heat the tank.
It looks like it will be significantly cheaper to heat a hot water tank with gas than with electricity.

I think I've got this correct. These costs are notwithstanding significant standing charge increases.

[monabri]

I thought an immersion heater element was 3kW and it typically takes 2 to 3 hours to get to temperature (60'C).

https://www.which.co.uk/reviews/home-he ... Jd38H0aHNq

So , 3kwh x 2.5hrs x £0.28 =£2.10

Of course, one would heat the water using Economy 7 if possible. I'm still waiting to find out the rate for Eco 7 units!

[monabri]

I thought an immersion heater element was 3kW and it typically takes 2 to 3 hours to get to temperature (60'C).

https://www.which.co.uk/reviews/home-he ... Jd38H0aHNq

So , 3kwh x 2.5hrs x £0.28 =£2.10

Of course, one would heat the water using Economy 7 if possible. I'm still waiting to find out the rate for Eco 7 units!

I decided to look on their website.... so at best it will be 3 x 2.5*£0.20 = £1.50

Day unit rate30.501p per kWh
Night unit rate20.611p per kWh
Standing charge 248.213p per day *

[Mike4]

According to the usave.co.uk website, a kWh of gas energy was approx 3.5p and a kWh of electricity energy approx 19p in 2021.

Although I don't have a current price for a kWh of gas, even if gas prices have doubled or even tripled recently it will still be WAY cheaper to use gas than leccy for heating anything at all, not just hot water.

https://usave.co.uk/energy/average-uk-g ... -per-unit/

If you are using say a 40 year old gas boiler that is only 60% fuel-efficient and comparing it with heating water with off-peak Economy Seven leccy, you might begin to approach parity.

[scotview]

According to the usave.co.uk website, a kWh of gas energy was approx 3.5p and a kWh of electricity energy approx 19p in 2021.

The average new variable tariffs post 1st April '22 will be, gas 7.3p/kWh, electric 28.0p/kWh. So gas will be even more cost effective than it is now.

This is kind of counterintuitive to the Gov. drive for changeover to electricity.

What energy policy ???

[88V8]

According to the usave.co.uk website, a kWh of gas energy was approx 3.5p and a kWh of electricity energy approx 19p in 2021.

The average new variable tariffs post 1st April '22 will be, gas 7.3p/kWh, electric 28.0p/kWh. So gas will be even more cost effective than it is now.

This is kind of counterintuitive to the Gov. drive for changeover to electricity.
What energy policy ???

They were talking about switching the 'green taxes' over from electric to gas.
Sounds too logical to happen.

V8

[scotview]

They were talking about switching the 'green taxes' over from electric to gas.
Sounds too logical to happen.
V8

Aye, but maybe they are a bit wary of big shift to electricity in case the grid collapses. Energy strategy is maybe being really well managed or they just don't know what they are doing.

[NotSure]

According to the usave.co.uk website, a kWh of gas energy was approx 3.5p and a kWh of electricity energy approx 19p in 2021.

The average new variable tariffs post 1st April '22 will be, gas 7.3p/kWh, electric 28.0p/kWh. So gas will be even more cost effective than it is now.

This is kind of counterintuitive to the Gov. drive for changeover to electricity.

What energy policy ???

As pointed out on another thread, wholesale gas prices are currently around 500p/therm, or 17p/kWh. Electricity generated from gas will be higher still, but if current prices become the new normal, then it seems likely that the difference between the costs of heating with gas and electric may get much closer without intervention. Currently, gas users are effectively being heavily subsidised.

[Mike4]

According to the usave.co.uk website, a kWh of gas energy was approx 3.5p and a kWh of electricity energy approx 19p in 2021.

The average new variable tariffs post 1st April '22 will be, gas 7.3p/kWh, electric 28.0p/kWh. So gas will be even more cost effective than it is now.

This is kind of counterintuitive to the Gov. drive for changeover to electricity.

What energy policy ???

As pointed out on another thread, wholesale gas prices are currently around 500p/therm, or 17p/kWh. Electricity generated from gas will be higher still, but if current prices become the new normal, then it seems likely that the difference between the costs of heating with gas and electric may get much closer without intervention. Currently, gas users are effectively being heavily subsidised.

If gas prices rise accordingly, i.e. to 17p/kWh plus a profit margin for the billing companies, then there will be a headlong rush to change to oil-fired heating I predict.

And if leccy generated from gas is priced accordingly too, once transmission costs are loaded in I guess 60p-100p per kWh would be likely. In which case it will become viable to run one's own generator in the shed for household base load at least, and just use the grid for cooking the Sunday lunch.

As it is I reckon each loaf of bread I make costs me more in leccy than it would cost to buy a similar loaf in Tesco!

[BullDog]

According to the usave.co.uk website, a kWh of gas energy was approx 3.5p and a kWh of electricity energy approx 19p in 2021.

The average new variable tariffs post 1st April '22 will be, gas 7.3p/kWh, electric 28.0p/kWh. So gas will be even more cost effective than it is now.

This is kind of counterintuitive to the Gov. drive for changeover to electricity.

What energy policy ???

As pointed out on another thread, wholesale gas prices are currently around 500p/therm, or 17p/kWh. Electricity generated from gas will be higher still, but if current prices become the new normal, then it seems likely that the difference between the costs of heating with gas and electric may get much closer without intervention. Currently, gas users are effectively being heavily subsidised.

If gas prices rise accordingly, i.e. to 17p/kWh plus a profit margin for the billing companies, then there will be a headlong rush to change to oil-fired heating I predict.

And if leccy generated from gas is priced accordingly too, once transmission costs are loaded in I guess 60p-100p per kWh would be likely. In which case it will become viable to run one's own generator in the shed for household base load at least, and just use the grid for cooking the Sunday lunch.

As it is I reckon each loaf of bread I make costs me more in leccy than it would cost to buy a similar loaf in Tesco!

Oh my, I hope not. My daughter's apartment would costing more to heat than the mortgage and council tax combined. Fully electric apartments would be unsaleable. (Many are already zero value and unsaleable due to cladding issues, my daughter's included).

[Mike4]

As it is I reckon each loaf of bread I make costs me more in leccy than it would cost to buy a similar loaf in Tesco!

Oh my, I hope not. My daughter's apartment would costing more to heat than the mortgage and council tax combined. Fully electric apartments would be unsaleable. (Many are already zero value and unsaleable due to cladding issues, my daughter's included).[/quote]

Point of Order M'Lud...

I think despite cladding issues, such flats are sellable at a suitably knocked-down price to cash buyers willing to take on the risk of the unknown future expense. Possibly a LtdCo buying so it can go bust if the eventual remedial cost demanded is stupidly high.

Unmortgageable though for a normal buyer, I agree.

[BullDog]

Around a 60% discount to a cash buyer. Yes. I would imagine, but I don't know, it's only the truly desperate who would take such an offer. Anyway, no more on that from me, apologies for raising off topic posts.

[DrFfybes]

Having lagged our tank a month or so ago, I've been measuring flow temps, heating times, costs etc.

I have found that having the hot water from the boiler for 20 min from 7am is not quite enough to keep us going.

However I have found it uses about 5kWh/day of gas, which currently costs 7p/kWh, up from our previous 2.8p (both plus VAT), so about 35p.

Running the 3kW immersion heater for 30 min whilst I do brekky (so 1.5 kWh, worked out as about 3 times as long as we spend in the shower which would typically be 9kW 'heat on demand') has a similar effect, OK for a couple of showers but that's about it. Electricity is now 26.5p up from 16.7p/kWh, so costs us 40p.

So, given a 250% increase in gas compared to a mere 150% increase on our electric, it is now pretty marginal which is cheaper for us, gas probably still has a slight edge.

However using the gas is a lot simpler, as that has a timer and I don't have to remember to set the cooker timer to remind me to go upstairs to turn the immersion heater off.

Paul

[BullDog]

Having lagged our tank a month or so ago, I've been measuring flow temps, heating times, costs etc.

I have found that having the hot water from the boiler for 20 min from 7am is not quite enough to keep us going.

However I have found it uses about 5kWh/day of gas, which currently costs 7p/kWh, up from our previous 2.8p (both plus VAT), so about 35p.

Running the 3kW immersion heater for 30 min whilst I do brekky (so 1.5 kWh, worked out as about 3 times as long as we spend in the shower which would typically be 9kW 'heat on demand') has a similar effect, OK for a couple of showers but that's about it. Electricity is now 26.5p up from 16.7p/kWh, so costs us 40p.

So, given a 250% increase in gas compared to a mere 150% increase on our electric, it is now pretty marginal which is cheaper for us, gas probably still has a slight edge.

However using the gas is a lot simpler, as that has a timer and I don't have to remember to set the cooker timer to remind me to go upstairs to turn the immersion heater off.

Paul

We have 7p per unit electricity 00.30 to 04.30am. Rest of the day it's around 40p. Gas is now 11.5p which is around 3x what it was a few weeks ago until the contract ended. I expect another increase in gas price in October and again in January. The electric price is fixed for a year. Will have to think about whether electric or gas is the best way to heat a tank of hot water in summer when the heating isn't running.

On the other hand, in winter when the gas heating is already running, it's probably more effective then to use the gas heating for water heating too.

[tjh290633]

We had our kitchen remodelled late last year. One thing that concerned me was the amount of water which had to be drawn off before it ran hot. It is a long way from the tank to the kitchen tap.

Consequently I had an undersink water heater installed. Very well insulated and close to the tap. It now needs just a small volume to be drawn off before hot water is provided. The installation required a pressure relief valve and an expansion chamber. Water temperature can be adjusted to taste.

The outcome seems to have been a reduction in both gas and electricity consumption. They are now at historically low levels.

Note that this is not a Quooker set up. It cost about a quarter of what they quote.

TJH