Hey Rob-G,
How quickly did Octopus move it all forward with yours?
Just found this thread today… reached out to Octopus mid-last week as I also suspect our 9kW is oversized - was a fairly early install with a surveyor on his first job both as surveyor and team lead (!); spends the majority of its running time at minimum output and it looks like they’d double counted some of our rooms in the original heat loss survey…
Surprised to have Octopus get back to me within 24h to arrange another survey (booked for tomorrow) without so much as a question. Will be interesting to see what happens but they certainly seem willing to listen to concerns, which is probably good.
Appreciate the info’s probably elsewhere but when was your 9kW installed out of interest?
Cheers!
Mine was installed in October 2022.
I first questioned the performance with them in December 2022 so it has been more of a marathon than a sprint.
I suspect you will get action much quicker as a few of us have proved there was a problem either with their surveyors or the software they were using.
I gave them my own heat loss calculations using Heatpunk and provided graphs of the power use to show the cycling there was a lot of too and froing with checking config etc.
I think it was May this year they originally agreed to replace the heat pump.
I imagine they would have changed it quicker if I had pushed them a bit.
I wasn’t in any particular hurry as long as it was done before the weather turned.
Even with the initial poor COP the running cost were about the same as a boiler due to my solar, battery storage, and being on Intelligent Octopus but my running costs are probably about to half.
Thanks, that’s all good to know. Will see what comes out of tomorrow’s survey & go from there.
Ours went in during August 2022. Curious now if most of the “problematic” installs all happened before the 8kW’s became widely available perhaps?
Had a few conversations with O since install about efficiency and reducing flow temps, and we’d obviously noticed the 900w floor on power consumption. Still costs less than running our oil heating though especially throwing in solar, batteries & intelligent; so all good… just could be better without the 900w idle!
We had a 9kW Daikin installed by Octopus at the end of May 2023. We were told we were borderline between needing 8kW and 9kW and a chimney that was missed on the first survey tipped us over to needing 9kW unit.
9kW is probably too big for our house and I’m sure we’d get much better performance from an 8kW unit, as we are regularly running near minimum power. But I personally can’t face pushing for a replacement. We just have the heating go off for a while once the temperature is reached… not perfect, but we’re used to it from having a gas boiler. We’ll wait for next heat pump for 24/7 modulated running.
However, I’ll keep torturing myself by watching this thread
If you think it’s oversized contact Octopus. They will do another survey and let you know.
It was important to me to get it sorted because I advocate for renewables and low-carbon tech, I wanted to recommend heat pumps and Octopus to colleagues, friends, and family with the heat pump I had I could not.
Happy to discuss the process further if any of you need a y assistance with this.
If you go to Octopus and give them a survey by an independent party (or heatpunk) and show them the day from the heat demand page on open energy monitor it should show your heating needs.
If this is under 7.3kW then you should have the smaller unit. If it is borderline you really should try additional insulation first.
Remember you only need the full power for around 10 days a year so for the rest of the time it is oversized. Personally I would rather have a jumper day or two or use a fan heater occasionally (I have never needed to).
Let’s restate what I think is the key point: the real problem is not that that the 9-16kW Daikins are “too big”, it’s that they have a minimum useful/efficient output of around 3.6kW (900W minimum input power * COP). And almost any property will find that too much heat output for many hours of many days.
So we don’t really want a smaller peak output unit, we want a unit that modulates down to a more typically useful range.
Thanks for the offers of help, but I’m going to keep my 9kW (for a useful working lifespan).
But in this case the 9kW modulates down no lower than the 16kW unit as they both use the same compressor.
They both also have a massive circulation pump, it is so big that it uses nearly as much electricity as the truly smaller 8kW unit modulated down to its lowest output.
When you buy the 9kW Daikn you are not actually getting a smaller heat pump with the ability to modulate to a lower output than one sold with twice the output.
I’m afraid I don’t know of any publicly available firmware files for FTC5 - I’ve only ever had updates performed by heat pump engineers. Best talk to your installer.
