Advice on a Daikin Altherma 3 by Octopus

Wizard2

Hi! I've been given a quote for a Daikin Altherma 3 (EDLA08E2V3), and am seriously considering it. The quote is just shy of £4000, which I don't think is too bad. I haven't had any other quotes, but Heat Geek estimated over £6000 on their website. Octopus would replace all but one radiator. I'm in East Anglia and the radiators have 10mm copper pipes.

The reason I'm posting is because I'd really like to see if anyone else has gone ahead with Octopus/the Daikin Altherma 3, and what your experience has been like. Octopus told me they've done 'thousands' of installs in the area - does anyone know if that's true?!

One of my main concerns is the efficiency of the system, since Octopus design for a 50°C flow temperature. I was told I wouldn't be able to change the temperature - is that correct? From what I've read, people have been able to adjust it to improve efficiency. What sort of SCOPs are people getting with the Daikin unit?

Another concern was the refrigerant used, R32. It's not as environmentally friendly as R290, which Vaillant use. Is anyone worried about that, and it being discontinued in the near future?

Finally (for now!), what was the thermostat installation like? Did new wiring have to be run the whole way, or could wiring from an existing thermostat be used?

PS. I suppose one other question - does anyone regret switching to a heat pump? Would it be hard to go back to gas if we really hated it (the gas boiler is our last gas appliance)?

FreeBear

Wizard2 said: I'm in East Anglia and the radiators have 10mm copper pipes.

Would it be hard to go back to gas if we really hated it (the gas boiler is our last gas appliance)?

Is it just 10mm going to the radiators from larger pipes, or is the whole system plumbed in 10mm ?

If you find an ASHP unsuitable, as long as you still have a gas supply, it wouldn't be too difficult to reinstate a boiler. If you kept the ASHP as part of a hybrid system, you'd be able to run the HP at a high COP on the warmer days, and just use gas for a boost when cold outside. To convert to a hybrid system wouldn't be very cheap though. The money would be better spent on replumbing the existing system (bigger pipes, larger radiators) and improving insulation levels.

Adrian_Dorr

 Whey mean is that you can’t can’t change the design temperature. Using a weather curve setting the system will constantly change the temperature and only go to 50C when the outside temperature is at the design temperature, I.e. the minimum outside temperature that you get at your location (e.g. -2C in the south). 

You can change that in the settings later when you find that your house gets too warm. 

Exiled_Tyke

They are pretty poor at explaining this. I got my final handover documents with the 50 degree figure quoted alongside a table showing how COP deteriorates with higher temperatures.   However as Adrian says, it's not quite as simple as that (fortunately).  My system is averaging a flow temperature of about 32 degrees at the moment.  Minor adjustments to this are possible if the house heats to quickly or slowly, in the settings screen.   The key is opt for the Daikin controls. Some people opt to keep Hive which has more functionality in other areas but isn't designed for an ASHP so cannot take into account the outside temperature and will run at the least efficient COP.   (For the record I have the Daikin controls and app to mange the ASHP but still have Hive to manage my TRVs). 

gradgrind

I had an Altherma system installed by Octopus in June. Mine was very simple and being a 2014 house, very low heat loss. They replaced two radiators, one in my home office so it gets to living room temperature, and one in the kitchen where we’d removed one as it gets too hot.
Would be interested to hear from other owners if you’ve changed any of the default settings - beyond room temperature and times.
Mine was £1050 after the grant. 

matelodave

I would think that most systems would be installed and commissioned using either default or calculated settings which may or probably may not suit your real life requirements or lifestyle and so need a bit of tweaking to get it just right.

Its pretty easy to get overwhelmed by the number of options available, especially if you get into the commissioning and engineers menus. The addition of programmable stats or something like Hive or similar just compounds the number of options to make it all go awry. In a lot of cases additional controls just compromise the operation of the the system and increase the power consumption especially if they cause increased on/off cycling.

My approach when we got ours some 14 years ago was to do quite a bit of tweaking and measuring BUT I did set up a spreadsheet with all the options and settings, only changed one thing at a time and recorded what I did, when I did it and what the result was, giving it enough time for a tweak to take effect - at least a day or two. Taking into account the weather as well.

Heatpumps are very sensitive to quite minor adjustments so only make one small change at a time and record what you did and what happens.

Nick_Dr1

Octopus did mine in August so it hasn't really had to do much so far. Its currently operating at a COP of about 3.5.
Ours has 10mm copper as well and they replaced nearly every radiator. I wouldn't worry about the refrigerant. Its supposed to stay in the system anyway, and there isn't that much.to start with.
You can twiddle all kinds of settings. They can only fit wired thermostats at the moment and placing this is key.

Insulation makes the biggest difference though. Octopus won't fit anything unless they are happy it will work well.

Exiled_Tyke

@Nick_Dr1 how do you get hold of COP figures? 

In response to other questions.  Like Nick my ASHP hasn't been tested much so far.  My initial thoughts are: 

1. I'm very happy. I particularly like the more gentle constant heat of lower temperatures throughout the house. (not great for drying towels on the towel rails though) 

2. I also like having a cylinder rather than the combi boiler I had before. (especially hot water running through more quickly)  As I have an EV tariff heating water at night is substantially cheaper than gas heating. I also get the ASHP heating the house during the cheap rate in the early morning (the initial power up of the ASHP is quite energy heavy) 

3. It is taking some getting used to. As it is slow to heat up you can't just turn it on when you need it. But I'm sure that a higher base temperature is better for the house than how I ran the gas boiler.  

4. Octopus were a pain getting to installation. Pretty much everything that could have gone wrong did. A lot of it related to a restructuring of their teams and new staff taking over the project. Hopefully they are through this now.  From installation onwards they have been very good. The installers were very friendly and helpful. Post installation queries have been dealt with very promptly. 

5. I'm pleased they were able to keep my Hive TRVs in place. Turning radiators on and off frequently doesn't work with the approach needed to get the most out of this method of heating. However I have a few rooms which I only use at certain times in the week so having these programmed ahead is still useful.    

6. Overall with the removal of gas from the house; careful (shrewd/astute?) use of the night time tariff and also firing up on an afternoon while I still have some spare electricity from the solar panels means that I expect to make some savings over the old system. However I'm sure the worst days of winter will test this theory. 

Nick_Dr1

To calculate COP:
From the settings box on the wall, you can manually get it to tell you the electrical energy used and the heat energy output. Divide one by the other and there you go. Its not that convenient but its about the only way unless you install third party sensing systems.

If you are technically minded, you can connect your Altherma Heat pump to something like Home Assistant for more convenient monitoring, but Daikin currently don't expose all the sensor readings to their API so you can't get COP that way.

You can get it though by connecting to the modbus interface in the heatpump. This allows you to read all the available sensor data. You can then send this to (again) home assistant and that will allow you to calculate the COP automatically. You need to have some programming experience but it has the advantage that you don't need to add any new sensors.

You can of course add your own current meters (for input power) and temperature and flow meters (for calculating heat output) but this is expensive and requires draining the system. Worth thinking about though if you are having a new system put in and you are a data nerd.
See here for some further information Heat Pump Monitoring — OpenEnergyMonitor 0.0.1 documentation

Adrian_Dorr

This might help: https://youtu.be/-EUeqDSv5ag?si=5aRjkQc7zZqnL5Zt

Nick_Dr1

You can look here for some data on the actual performance of installed heatpumps
HeatpumpMonitor.org