Posted by: @jswhite

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Hi Bob77 Your result sounds like the one I was looking for and your heat pump is half the size of the one that was fitted in my house. Can you tell me the area of your house and the daily cost when the temperature was so low?

My house is a three-bedroom 1960s end of terrace which we have recently extended on the ground floor. Total area according to the EPC is 117 sq metres.

My electricity bill for the last month was £405 but this has also included a lot of laundry and vacuuming due to clearing up after building, plus lots of doors open with tradesmen coming and going. Also I think the HP was set too high for much of the time as I was still tinkering with the curve.

The peak daily consumption (heating plus DHW) during the cold spell was about 30-35 kWh I think - although I'm not sure if there is a way to get daily data from more than a week ago on the Daikin screen.

We are on Economy 7 with rates of about 25.9p overnight and 39.8p in the day so I'm experimenting to see if turning the timed thermostats to call for heat in the cheap period can keep the house warm during the day at less cost.

I voted very pleased because whilst I am happy with the system overall there were definitely installation issues that are still not resolved, although I do not blame my installer for these. I think the main problem is that the whole thing was rushed when the installer was already very busy. I don't think this country's installers (at least where I am) are in a fit state to get an installation done quickly when a gas boiler breaks, as was my case.

Posted by: @jswhite

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Hi Bob77 Your result sounds like the one I was looking for and your heat pump is half the size of the one that was fitted in my house. Can you tell me the area of your house and the daily cost when the temperature was so low?

Just to expand on my previous answer, in the recent milder weather with daytime temps of 9-10C and nights staying well above zero the daily usage seems to have settled at between 12 and 17 kWh, generally in the lower end of that range. That’s with the house kept at 20-21C all day downstairs and DHW set to 52C overnight with a reheat to comfort temp of 47C in the early evening. We have often had the wood burner going in the evenings too which obviously will have reduced/eliminated the call for heat - fire is not really needed for heat but we like the ambience as it’s the focal point of the downstairs space. 

With the WC curve the flow temperature during the day recently has generally been around 37C which seems to work well. 

Daikin Altherma 3M EDLA09DA3V3 ASHP + 200 litre tank. Cost £13K less £5K Boiler Upgrade Scheme discount.

High quality equipment, but very complicated tricky controls, only suitable for nerds and geeks (like me). Needs 3 power supplies. Many many many tricky settings. Clunky display interface. Subtle bugs.

Installation began 5 Jul 2022, still unfinished at 2 Jan 2023.

Truly dreadful, awful hopeless supplier, could not care less customer service. No Daikin experience at all, used poor subcontractors. Damaged my house, still waiting for repairs.

NAPIT seems to be forcing them to complete the installation.

So far, using figures from the Daikin display, COP about 2.6 (45 degrees water flow, 19 degrees room temp), 1.6 in very cold week (-10 to 0) when the system spent nights frosting and defrosting, creating a glacier of ice before it. But it kept us warm, at enormous cost of electricity. Now testing 35 degrees water flow.

This model has A+++ rating and fabulous COPs, > 4 - but not for me.

Daikin customer support seems very good but have not yet paid them to visit.

I think the root of the problem is the shortage of Daikin trained tradesmen. Plumbers are totally lost and electricians scratch their heads and drift away.

Discovering this forum is the best thing that's happened this year. THANKS !!!

Posted by: @rayh

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Daikin customer support seems very good but have not yet paid them to visit.

I think the root of the problem is the shortage of Daikin trained tradesmen. Plumbers are totally lost and electricians scratch their heads and drift away.

Welcome to the forums. I can’t understand why manufacturers sell their products to installers that have zero training or knowledge of their products. 

Ray, feel free to start a new topic dedicated to your system, and please tell us what the installation dramas and delays.

I voted average because whilst it all works roughly - the system is way too complex. There are four ways to change the settings! Installers in my opinion need to get real, recognise that people are not very interested in the intricacies, and set things up so they are likely to work (with tweaking at the, say 6 week, 6 month, and 2 year point).

I went to 4 recommended companies 3 of which are no longer in business but gave us the run around for months and the 4th charged £300 for the heat loss calcs and wouldn’t install a system as he’d never done one so big… 

The initial system was going to be GSHP but the length of pipe work from the calculations varied by 600m! Then the cost to run pumps to factor 1.8km was astronomical. 

So many things they all said could and couldn’t be done all contradicting each other.  We decided to use a commercial M&E contractor with a domestic arm to install a Mitsubishi designed system.

Posted by: @rayh

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I think the root of the problem is the shortage of Daikin trained tradesmen. Plumbers are totally lost and electricians scratch their heads and drift away.

Discovering this forum is the best thing that's happened this year. THANKS !!!

Absolutely! This forum is how my Valiant system got set up. It was installed by a plumber who had no idea at all. I'm getting towards being happy with it. 

My ASHP was installed in 2008/9. It was the wild west back then, and it's been a bumpy ride, but it now works OK ish, although expensive, I think (mainly due to electricity cost escalating than energy use). 

I'll do a thread on may experience at some point, but I must say my heart goes out to the people who have had a really bad time here. 

Also: as mentioned above, I'm really glad to find this forum. I've joined a number of renewable energy forums over the years but there's clearly a high level of experience and knowledge among the posters here!

@pressure, welcome to the forums and look forward to hearing about system. I’m afraid the ASHP Wild West is still pretty wild! 🤠

I hate to come across as biased:-), but just finished a DIY install of a 16kw Gen 6 Samsung HP, replacing oil.  I am pretty happy with the whole setup.  It took about 9 months of educating myself, learning how to do plumbing a bit better, and building a reasonable understanding of what the best setup is and then doing the install.  Turned it on at 2:30 am on 24th Dec 2022.  Average COP so far 3.6.   I think the hot water is dragging it down as I have been getting over 4 occasionally (best day was 4.2).  Am in the process of trying to integrate it with home-assistant, early days though, and have just got the pump connected via modbus.  Ultimate goal is to do a diy homely type setup for the purpose of learning more.  That will probably take another year or so.

I went for one pump and one zone, no volumisers, no glycol (used anti freeze valves), no low loss headers or any other mixing solutions, ran 28 mm pipe as far as I could (into two manifolds), I put UFH in living space and bathroom, kept original radiators in the rest of the house.  All running on the same temperature.  (rest of house will over time be converted to UFH, so we live with the other rooms at 18 and the living area at 22).  Went for 100mm UFH spacing with max 50m circuits (over kill, I know, but all with the end in mind), will do the same for the rest of the house when we get there.  All with the goal of that record breaking COP :-).

I am enjoying reading all the posts on the site and continuing to learn.  Learnt yesterday that I should have installed a PWM pump, am in the process of planning a fix for that in the coming weeks, hopefully that will make a difference.

Posted by: @william1066

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Am in the process of trying to integrate it with home-assistant, early days though, and have just got the pump connected via modbus.

First, congratulations, it must be very satisfying having a working DIY installation.

I'm very interested in your success in getting modbus integration with Home Assistatant, as I am trying to do the same thing with a Midea heat pump, which also has accessible modbus (RTU/RS-485) terminals (A and B), Would you care to go into a bit more detail on how you set this up, what hardware/interfaces etc and how you joined everything up. At the moment, I am exploring using an RS-486 to USB converter (+/-ESP32) and doing the whole thing wired for simplicity and robustness, but I am still at the concept stage. I'd also be interested to know what you are running Home Assistant on. I currently have a PC version but it is hobbled, it seems you only get the Full Monty on dedicated hardware.