Glad to hear it all went well; I wanted to use Octopus for all the reasons you have experienced, it was just that at the time of the survey, they had not progressed to the point where my installation would have been ‘within scope’ as they put it then. Very good chaps and I have always found their teams on the road and in the offices to be excellent. Regards, Toodles.

@lucia And just to add, the Daikin ASHP is very good but it is a shame their manuals and their programmers are such cr@p. Ours is controlled by Homely now but the installers fitted the MMI and a stupidly dumb Neo thermostat initially! As soon as Homely came along for the Daikin EDLA08 with a secondary pump - with jumped for it! Regards, Toodles.

@lucia Further, I would like to add that using WC on the Daikin is impressively good at maintaining a constant IAT - except at the extremes (particularly on the milder end) where I found manual tweaking was required sometimes. Mind you, we are super fussy in our requirement of 22.5 degrees C at all times and not deviating by more than 0.5 degrees! Very happy with the system - just the appalling energy prices tagged to the possible use of gas in generation plants! Kill the Spark Gap I say! Regards, Toodles.

@lucia Thanks for the update post installation. Also, thanks for posting the link to the original thread. I must have missed that completely. Going through that thread in detail made me realise that the quote I have received from Aira may not that different from Octopus after all. If Octopus insist on 50 degrees flow temperature, then I think there shouldn't be more than two radiators changes in our case. I did play around with Heat Punk and heat loss of most of our rooms are well below the radiator outputs at 50 degrees flow temperature.

Aira is happy to offer two radiator changes as part of the original discounted quote, but their prices are still slightly higher. I was leaning towards Octopus as their online quite is for replacing as many radiators as needed for our home after the survey, but still much cheaper than Aira. And Aira confirmed that their quote includes 15 year warranty and I don't have to pay for annual servicing. The first figure Aira quoted for any radiator changes needed was almost double Octopus' quote. I couldn't justify that much of a price differential. But, if Octopus aren't going to change any radiators due to their design, then probably the quotes are kind of similar.

Or maybe, I should go with Octopus but just ask for more radiator changes so that I can tweak the flow temperature post installation like you did. Either way, thanks for the very useful update.

@toodles hi how does the Homely thing work please, is it complicated, expensive?

@boycey The Homely price was £370 plus fitting but I can’t work that component out as it was contained within a day’s labour whilst other installation work was been carried out. As to how it works … Very Well!

OK, to be more helpful: The Homely controller interfaces with the heat pump’s control circuitry via Modbus. In the case of Daikin, there is a D.comm unit and the Homely talks to this and the control signals are sent to the heat pump using P1 and P2 connections. Homely constantly monitors many parameters and controls the flow temperature, monitors the OAT, the IAT, the delta T of the heat pump’s circuit. Homely also makes allowances for solar gain, uses TOU tariffs if required and proactively adjusts the heat pump having ‘learnt’ the system’s needs and your comfort requirements over a week or so. As Evergreen Energy explain it, it is like having an engineer micromanaging your heat pumps 24/7. My installation is in the airing cupboard, has 2 PSU’s on 13 amp plug bases that power the Homely unit itself and the other for the D.Comm unit. There is a ‘node’ (temperature and light sensor) that you place in your favoured room such as the sitting room and this communicates to the Homely controller via Zigby. The app is available for IOS and Android and allows for all the programming of schedules, temperatures, TOU tariffs and other preferencces too. See my review on RHH which I will post presently. Regards, Toodles.

@boycey The Homely Review may be seen at:

https://renewableheatinghub.co.uk/homely-smart-controller

Regards, Toodles.

@toodles thats great thanks very much. do you have any data for before and after having the homely, that would be interesting to see if you did?

@boycey Sorry, but apart from my provider’s energy bills that are for all consumption, no. The Onecta app is next to useless and I do not have any meaningful long term energy use trends* as before I moved to Octopus, I was with a provider who could / would not read my meters or provide sensible billing details. From my own calculations, I am using less energy now on electricity only than when I was on gas as well and had a gas boiler for heating.

*I have made so many changes and improvements to our property over the last 3 or 4 years that I feel the situation has been a moving target. Please see:

https://renewableheatinghub.co.uk/green-transformation-my-journey-to-a-sustainable-and-energy-efficient-home

for just some of the improvements.

My gut feeling is that as I have spent / invested £Many on Solar, Battery, ASHP, Insulation etc., I ‘must’ be paying less than I did for heating when on gas and even less now with Homely.😉 Regards, Toodles.

@lucia And even further… I have rarely been out in the garden at the right time to notice a defrost cycle but yesterday I just happened to pass the pump and noticed a very impressive plume of steam! I checked on the Homely dashboard today and noted that with the OAT hovering around zero degrees C for the whole 24 hours, the pump defrosted 10 times and takes approx. 8 minutes from start to finish. Once or twice over the last year or so, I have noticed a cold area at the base of the radiator panels for a few minutes then we are back in business. Regards, Toodles.

@toodles I've not been able to catch a defrost so recorded a time lapse video (view with link, file is mp4 about 44MB).

This was taken at 1 second intervals over about an hour from 8am to 9am. Running time is about 2.5 minutes. The outside air temperature was 2C.

A bit like watching paint dry but you can see several defrost cycles over the time period. It had already done a few before I set up the camera. Nothing to celebrate as each cycle represents use of a lot of electricity.

Mike