@toodles Partial answer to my own question!
EV is 100% full after charging today. I see slots for tomorrow are:

Start Time: Thursday 6th February 23:00
End Time: Friday 7th February 08:00

So giving me 9 hours at 7p. Excellent!
Counterintuitively I guess I need to boost my overnight heating (not setback) to maximise ashp at 7p as well as fill batteries. No big problem.

Batteries full at 8am will not be enough to get me through a cold day - but will go long way.

Maybe Octopus will give another hour or two cheap slots during tomorrow? We shall see. Interested to hear how other IOG users get on. Guess I should trigger under an IOG thread...

Really interesting thread, thanks for the insights everyone.

We recently had an Aira heat pump installed, and straightaway I realised that we need to be on the Cosy tariff for our setup. We have an EV, but very low mileage and is not compatible with Intelligent Octopus Go. We do have a decent size PV array, but due to trees and staggered layout of houses near us, we get a bit subdued solar generation in winter (but picking up nicely come February). The battery is not large enough to last the day in winter even before heat pump was installed. We were on an EV tariff but the battery would be depleted by mid-afternoon even before the heat pump was installed.

Switched to Octopus for everything, including Outgoing Octopus, and as soon as the smart meter was connected to Octopus, I switched to the cosy tariff from their default flexible tariff they put you on during the switch. Even while I was waiting to switch to Cosy, I set the battery and EV charging as if I am on Cosy for the last couple of days on Flexible Octopus, and it was clear to me that Cosy is the right tariff. If my calculations are right, we should average around 13 pence per kWh in the winter, and near zero imports in late spring, summer and early autumn. I have set the DWH schedule during the 1 pm.to 4 pm cosy window, and have asked Aira whether they can change settings at their end for optimising the heating. They do have an Aira Zero tariff with Octopus, so sure they can manage a small bump in heating during cosy window and setback during the 4 pm to 7 pm window. Even otherwise, we should save by running the heat pump on the cosy tariff. Not doing any export optimisation at the moment and endeavour is to maximise solar consumption and export any excess.

@chandykris . If you have the facility to check on your flow data, have a look at the timing  of when the DHW schedule kicks in.  I am on Cosy with a Samsung pump and mine starts to heat the DHW about 30 mins before the scheduled time, so I have timed mine from 1.30pm to be within the Cosy cheap period.

@broadsman That's a good shout. I can't see the flow data, but can see input power and delivered heat by hour. Also, can track input electricity on the battery app. I should set it to kick in a little later than 13:00 to be sure.

Conclusive evidence after 2 weeks on IOG.

Batteries plus extra daytime slots ensuring average is under 10p kwh/day

IOG 5th to 17th in pic - vast majority at 7p/kwh

1st to 5th Feb I was still on Agile 😱. Octoprice suggests my costs for 1st to 17th Feb if I'd stayed on Agile would be £276. Allowing for some changes in patterns of charging I suspect  it would be at least £240 anyway. If IOG for entire month I expect it would've been closer to £100

6th to 18th Feb 931kwh £71 = ave 7.62p

Ex-vat

Ex-standing charge

I switched from Agile to Cosy on 12th Dec, when the stupidly high prices started. We currently have a heat pump and no battery storage (do have solar but the impact is negligible in winter), and could not afford constantly high prices throughout the day as they become unavoidable when the heat pump ideally wants to be running constantly.

Anyway, having switched to Cosy, and with a little bit of ToU shifting usage around, we have our average import rate at around 20p per kWh (19p on a good day). The Octopus Compare App tells us Cosy has been cheaper than Agile for every day except a couple (less than 5) since we switched, although I note Agile prices are currently looking better today.

The heat pump is obviously the main consumption, and we've been getting COPs above 3 in the cold weather (and above 4 on milder days like today) which has meant the heating is costing less than the price of gas/oil, so overall we are happy with that. We are adding a battery which will drop our import costs further and add to ease of use/comfort as the time of use is effectively flattened across the day (no more trying to avoid usage at 4-7pm peak rate).

I may look at Agile again in the spring once our usage drops and solar makes a significant contribution - if we can charge the battery very cheaply and then export all our solar, then that might work well, but having to manage 48 half hour slots manually every day for charging/discharging will some become tiresome.

Posted by: @old_scientist

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…if we can charge the battery very cheaply and then export all our solar, then that might work well, but having to manage 48 half hour slots manually every day for charging/discharging will some become tiresome.

That, of course, is one of the major reasons several of us on the forum have adopted some form of home automation system. Well worth a look.

@old_scientist Yes, Cosy does seem to be the better option at present; though I may re-evaluate (they can’t touch you for it!) in the Spring. The Agile ‘Faff’ may be relieved by using the NetZero app as that can work with Agile and Powerwall and do the drudgery for you I believe though I have not used it for that tariff yet. One note: please check the ‘limitations’ that PW3 may place on some control of its’ workings with NetZero; there are notes about what they are in the NZ documentation. PW2 works slightly differently I believe. Regards, Toodles.

@old_scientist The last two days of Agile pricing shows a marked drop for the cheapest HH’s - perhaps a new trend is on its’ way? Rewards for some, Toodles.

Posted by: @toodles

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@old_scientist The last two days of Agile pricing shows a marked drop for the cheapest HH’s - perhaps a new trend is on its’ way? Rewards for some, Toodles.

@toodles

Two days don't make a summer (or something like that!). But yes, I'm watching it closely. I'm not sure I'm brave enough to jump back on Agile yet, whilst I'm still using ~30kWh per day with heating, but once we have the battery installed and can leverage cheap slots, and heating usage has dropped off. Well, lets see how things progress over the next month or so.

Bill through for Feb.. changed from Agile to IOG on 5th Feb

1477.2kWh @ 7.36p/kWh = £108.69 from 5th Feb to 28th

Helped by having batteries and Octopus offering extra daytime slots at cheap rates meant just 55kwh out of 1477 were charged at peak rate - and chunk of that was on 5th Feb (changeover date).

I was concerned my battery charge/discharge rate via older inverter 2.6kwh might be a problem - but in reality was minimal issue. 

Still using WonderWatt which captures the cheap daytime slots without intervention. Working extremely well. Can't imagine I'll be going back to Agile or changing again unless IOG terms change.

@tim441 Agile is still suffering higher prices than the tariffs it used to beat. Very little below 15 p. per KWh that I have noticed in some months now. I’m staying with Cosy at present (we don’t have an EV.) Regards, Toodles.