Old hot water cylinder - would it have been Economy 7 and can you return to it?

[robinbanks]

I see electricity suppliers offer other two-tier tariffs by time of use - presumably there's no need for two circuits these days?

It's handy to have two if you want the meter to do the switching I.e. to not rely on synchronised clocks to activate your high power devices when the electricity has gone cheap.
Back in the day storage heaters etc were on their own circuit because they didn't have timers that could eg activate them only after 1am when the electricity went cheap, so they relied on the meter activating a dedicated circuit for them when it switched to night rate

The immersion, on the other hand, probably would have its own timer and may need to be activated any time, night rate or not, so that would be on the "always on" circuit and you use the timer to choose when it consumes

 

[ericmark]

Note , you might find they require evidence that you actually have an EV

I have an EV tariff from British Gas, but Octopus want details of vehicle and charge point before on offer, and the peak rate did go up, worthwhile for me with batteries so use around 6–7 kWh per day off-peak, but my immersion heater in summer shows around 2.5 kWh per week, so if only used for that would lose more than gained.

I looked at the tariffs and the off-peak has a number of options, I have 5 hours, there is also a 7 hour, and a 6 + 1 hour, and 10 hour tariff plus variable tariffs, and they also vary supplier to supplier, I had intended to swap supplier, but locked in until April and found other suppliers do have a cheaper tariff but not available to me, so one needs to be very careful, it varies area to area as well as supplier to supplier.