Octopus messed up my initial survey saying we needed the 11kW Heat Pump.
Knowing better having done:
- Two different heat loss calcs that came to ~9kW +/- 10%
- Running our boiler range rated down to a max CH heat kW output of ~8.5kW @ ~45-50C flow temp and ~90% efficiency for two winters
- Signing up to Carbon Coop Powershaper.io service - Gas meter 30 minute interval on highest use day (140kWh for just space heating) over two winters showed maximum gas units used for a 30 minute interval was ~4.6kWh (so double to ~9.2kW input gas power over an hour @ ~90% efficiency to get back to the ~8.5kW heat output) - see below photos
They then proceeded to try and get me top upgrade to 3-phase (!!! WTF), as the test I was asked to do “run everything full pelt please” electrical load test came back as ~96amps - and I had already upgraded to a 100amp (max) fuse…computer said no, I had been given no context, and I was not asked to provide context of what I switched on (and what would not be switched on in reality together or when the heat pump was installed).
I convinced them through back and forth email they needed to re-survey, and sure enough it came back around 9kW unit (interestingly they have never divulged actual heat loss calcs ( 
)…has anyone else? (They have a radiator schedule that lists rads - but in my case UFH was not on there - and they also refernce the EPC(!) yearly demand, but thats it)
At the same re-survey, they also re-ran the “run everything full pelt” electrical load test (in which I didn’t run either of the 3kW immersions for example)…it came in at more like 60-70amps 
The 9kW Daikin unit was then listed on my MCS paperwork prior to signing.
They then delivered and installed the 11kW version ( 
), and didn’t tell me (I only realised when I went to register the warranty with Daikin as I wasn’t getting anywhere with it on the Octopus side, and made that outstanding discovery…
That said I did some research, called Daikin who said “don’t worry, not alot of difference” (they were right) and decided to keep it quiet as everything pointed to the minimum output (and input) being identical, and that was alway my worry to be fair.
It would appear I did the right thing I guess as CoP when I’m not driving it really hard on purpose during free or off-peak periods is pretty good. 
Given all of this, we were in a similar position to @matt-drummer in that no-one local heating engineer would go near a heat pump (the usual “they don’t work”, “house will be cold” etc.), there were no Heat Geeks for over 2 hours away from us so not practical.
I really want Octopus to succeed - we all need them to suceed. What is frustrating is they’re not appearing to learn.
