Using Octapus Go for Immersion heating

ImmersionvGas

I have a 180L unvented cyclinder which is currently supplied from my gas boiler. At current energy prices is it cheaper to fill this using my gas boiler, or use the immersion facility on it, using my 5p kwh overnight Octapus Go electricity?

MWT

The answer depends on how much you are currently paying for your gas...

... but it is likely that even if it is not cheaper right now, that some point soon it will become cheaper to use the electricity if you are exposed to the gas price going up after April...

QrizB

I've got Octopus Go. I'm currently paying 4p/kWh for gas but this will become 7.p/kWh in April.

I'm planning to heat my tank electrically on Go once April arrives.

My tank is smaller than yours so I'll probably need to top it up with gas in the evenings, but it will still save me a little money (10-15p/day).

[Deleted User]

I re-heat my HW cylinder overnight on Octopus Go Faster but it is not a simple ‘like-for-like’ equation. Even modern gas boilers are not that efficient when re-heating hot water cylinders as most boilers go to TMaxSet to reduce the cylinder re-heating time. There is also the issue of heat loss in the pipes between the boiler and cylinder.

My average gas usage when re-heating my cylinder was 6kWh a day. Electricity re-heating uses about 3.5kWh a day. However, as I am no longer heating my HW cylinder by gas, I have safely turned down my gas boiler CH flow temperature to 55C. This has markedly reduced my overall gas usage and boiler cycling rate. My total gas usage is now 7700kWh a year.

ImmersionvGas

Does anyone know of any web based formulas so I can input all my data to compare?
I am on Octapus Go's standard variable gas rate along with the 5p KWH electric at night.

[Deleted User]

ImmersionvGas said:

Does anyone know of any web based formulas so I can input all my data to compare?
I am on Octapus Go's standard variable gas rate along with the 5p KWH electric at night.

I am not sure what you are looking for? Using HH data it is pretty easy to get an accurate costs for gas and electricity usage for cylinder reheating in Apps such as BRIGHT. Monitor it for a few nights, and takeaway any background usage for electricity and you have your answers.