I’ve got:

5kW heat pump, but only 2.5kW heat loss, so max consumption of 2.5/3=0.75kW from the heat pump. 
9.5kWh battery. 

Solar doesn’t produce anything meaningful during high heating season, so I can mostly ignore it. 

As the battery would most days not be able to cover the whole days usage, cozy ends up marginally cheaper than go. I don’t think flux can compete in the winter. And agile is by definition difficult or impossible to predict.

@downfield Yes, I used to use Octopus Compare sp that I could check / compare; however, the comparison is as far as I know rather ‘retrospective inasmuch that the comparison is based on the times at which energy was used, rather than at what might have been different times if the other tariff had been employed. (IYSWIM). Using the ‘other’ tariff might well have meant utilising different times to obtain the best prices that day.

Anyway, for what is is worth, just for comparison, here is the chart for the last few days with OC. Regards, Toodles.

@tim441 As has been said before ‘changing tariffs very frequently’ is not a game I wish to join and just hope that sticking with one tariff should serve well. However, I think my main reason is for simplicity - should I be incapacitated or KTB, my wife would struggle with any system that required any manual input on a daily basis. There is a lot to be said for the KISS principle. With Cosy, I have the Yesla kit set up without a need to make daily changes - that isn’t to say I won’t look at Octopus’s EV tariff that doesn’t require me to have an EV once the main winter load has reduced…😉 Regards, Toodles.

Having mentioned that an EV tariff might be usable once the main winter load days have passed, (perhaps late January?) I then have the choice of going for that OE EV tariff that doesn’t require an EV or possibly Agile and use NetZero app to do the ‘faff work’ for me. Any reader have experience of using these two tariffs please? I haven’t looked into the use of NetZero with Agile as yet as I also have a Sunamp DHW heat battery in need of daily charging which would not be controlled from that app. At present, I have the Sunamp controlled from the Myenergi Eddi and it is easy to set the Cosy cheapest times so that they coincide with my charging times rather than drain from the battery. The 210 litre equivalent charge of the Sunamp more than copes with our daily needs so the EV tariff hours would allow sufficient charging time. on the face of it, the OE EV tariff looks promising…. Regards, Toodles.

Posted by: @toodles

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however, the comparison is as far as I know rather ‘retrospective inasmuch that the comparison is based on the times at which energy was used, rather than at what might have been different times if the other tariff had been employed. (IYSWIM). Using the ‘other’ tariff might well have meant utilising different times to obtain the best prices that day. 

Yes I take your point.  However, with an ASHP and batteries controlled on Agile by MyEO, I don't think it would be worth tinkering with my usage and therefore the OctoCompare between Agile and Flexible is - for me at least - is a very good indication of savings.

Although of course if I was on Cosy or an EV tariff then I suppose MyEO would charge the battery on a different schedule and that would make a difference.  But as I only have 19kWh it would still be overnight with a top-up in the early p.m. to get me through the peak.

We've been on Agile for a few years now. It's always expensive this time of year but as an overall average it works out OK for us. We don't have batteries yet but we do have 2 Ev's which we can charge fairly flexibly. On average over the year it works out around 15p/kWh for us.  I think we could do better if we had batteries we could charge overnight on a cheap rate but other than that I think we use too much during the day to balance out a 7.5p overnight cheap rate on Go or similar.

I agree that doing a direct comparison is nearly impossible with Agile as so much of it involves shifting use to cheap periods. With Ev's and batteries taking quite large amounts of energy in a short period it swings any numbers very quickly, as I found a couple of times in December when one of the cars charged during an expensive afternoon as I had forgotten to unplug it.

@toodles did you know that Myenergi will switch the eddi at the best times to suit Agile, or at least they used to.  I haven't looked at the app for a couple of years but it was getting very good at controlling the eddi and zappi easily when I last used it.

@johnnyb Hello johnnyb, yes, if I do resort to Agile again, I’ll investigate the Myenergi app - ISTR it was rather flakey nearly two years back but I suspect a lot has improved since then! Regards, Toodles.

@tim441 I have been checking the Agile rates over the last few months and, sadly, most days the cheapest seem to be hovering around 15 per kWh and often 20 p. or more. Perhaps this winter is a bit of a strain and Agile just isn’t going to reduce much again due to the ‘bonkers’ charging scheme.

I wondered if anyone on the Agile tariff has the data to determine whether the present situation reflects the last winter or two please? I don’t intend to swap back to Agile just yet but wondered whether any user is able to determine if the high rates are just seasonal and if in the past, they then dropped again in the spring perhaps? Regards, Toodles (Still on Cosy for now).

@toodles Yes I was on Agile last Jan and still am.

Jan 2024 I used c2000kWh and Agile cost was around 50% of Flexible.

Jan 2025 I used almost exactly the same kWh and the Agile cost has been 84% of Flexible.

I have 19kWh of batteries and am using MyEO to optimise charging, but my Agile usage has averaged around 21.6p compared to 14p last January.

@downfield Let’s hope that Agile is going to drop soon (But perhaps thats just a fanciful wish on my part!) Toodles.

I surrendered yesterday! Switched to IOG.

Bit messy as it failed to sync initially. Due to 2 zappi on the myenergi app (in different properties). Removed one... synced... then added back the other zappi. Bit messy but OK.

Pleased to see IOG gave me extra slots during the day - 2 hrs @ 7p plus the standard fixed 6 hrs overnight. With some good solar today I've almost avoided any standard rate imports. 

About 80kwh imported at 7p (half to ev) and 15kwh solar (best to assume 15p kwh nominal). I think 5kwh or less at 26.4p/kWh.

I don't know if I'll get offered cheap IOG slots in the day if ev is full? 

Today worked particularly well with solar but without solar and without solar gain through glazing I guess I might have averaged around 14 or 15p for house use alone?

As it's turned out I should have abandoned Agile sooner. But no disaster thanks to batteries and WonderWatt. Will continue WW with IOG for now.

@tim441 Thanks for the information Tim, seems as though Agile needs the user to be very agile these days! 😉 Toodles.