Using Electricity(Intelligent Octopus) in off peak instead of gas ( Octopus Tracker) ?

abeezar

Hi

I have an Electricity(Intelligent Octopus) and Gas ( Octopus Tracker) Tariff.

Electricity (fixed): 11.30 pm - 5.30 am - @ 7.5p/kWh
Gas Tracker ( Assumption 5p/kWh)

I have a heating system(Megaflow) that can operate on gas ( default) and electricity.
I have installed a smart switch to control on/off.

My daily usage of gas is ~ 1/3 in those (IO) hours. Example [ in Jan, daily 100kwh , so 33kwh in off speak ]

I wanted to know from experts if I use electricity in these off-peak hours , is that something going to save me by reducing my bill.

Thanks in advance.
Regards
AB

matt_drummer

Let's assume that your gas system is 90% efficient, your electricity is 100% efficient.

Your real gas price is 5.56p per kWh of heat produced (5.00/0.90)

Your electricity is 7.50p per kWh of heat produced.

It is cheaper to use gas.

33kWh of gas costs £1.65 and produces 29.70kWh of heat

29.70kWh of electricity costs £2.23

JohnPo

Am I thinking you are only talking about hot water only and not full central heating? Judging by your January usage of only 100KWhr then - perhaps hot water only sort of makes sense.

A system boiler being used just for hot water I don't believe is 90% efficient, you have all the pipework that gets heated, the boiler itself  plus the electricity cost of running the pump (parasitic loss).  I am not sure with your particular cylinder whether with electric it heats the whole thing - depends where the immersion heater is situated.  But gas is probably at least 75% to 80% efficient compared to electric overall.

I am on Intelligent Octopus and use the cheap rate, with a 300L tank and a 27 inch top fitted immersion.  I use the gas boiler on some days with flow temperature set at 55 degrees in late spring, summer & early autumn (guarantees condensing mode).  The gas boiler I use for most of the 'heavy lifting' when gas prices are lower than electric, the immersion heater is on a web based controlled timer to give a short 'early morning top up' and run a legionnaires cycle.  The gas boiler heats the whole tanks whereas the immersion only heats about the top 100L so depending on expected usage I have to make a decision on whether to pay slightly more per KWhr to heat less water or pay a lower price but get a tank full that we might not use.

In winter with central heating running the flow temperature on the gas boiler I run at 50, as the gas prices rise going into winter then I will time period the electric immersion runs for to try optimise getting enough hot water etc.

So actually depending on your setup and usage, might actually be are more nuanced decision. Of course when the central heating is on in Winter, the hot water usage is relatively minor part of your bill.