One year with an 8kW Dakin Altherma 3

Hardware Heatpump
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So, I have had it for a year.

Do I like it, not much, but maybe I have been harsh.

It has had some issues and focussing purely on efficiency, it could have been better.

I had to wait some time for a firmware update to allow me to run it how I wanted to and it has had a few occasions where it has used more electricity than it should have done due to some random inbuilt fault.

However, we have been warm enough, averaging about 20c upstairs and 22c/23c downstairs.

No failures.

It has been a colder winter than normal and for a while it felt like we were living in a cloud.

It has used 3,061kWh of electricity and produced 14,931kWh of heat at an SCOP/SPF of 4.88

The efficiency is pretty good.

We live in a four bedroom detached house and heat an all glass conservatory so not really ideal and is the root cause of many of my issues.

The heating system isn’t particularly great, installed by a clueless diyer with a fair amount of plastic pipe.

All I do have is massive radiators.

And that is all it takes, big emitters, the heat pump is bargain basement and the pipework is rubbish. But the heat pump is oversized and our heat loss is low.

The conservatory makes up about 40% of the heat loss of the whole building, so about 2kW out of a total of 4.5kw to 5kW.

I run it in the most basic form as that is what works best, fixed lwt with no room temperature control and no wdc.

The heat pump has been 100% reliable and is virtually silent in operation at all times.

In conclusion, despite my whinging, it works, it has been installed well, and it is efficient.

My actual electricity cost for one year is 214.27 at 7p per kWh on Octopus Intelligent Go.

I have sufficient battery storage to use that at all times and if I allow 20% for battery losses my costs would be ÂŁ267.84

That is for space heating and DHW.

If I were on a standard tariff at 25p per kWh then my total costs would be ÂŁ765.25

A gas boiler would have been ÂŁ995.40 at 90% efficiency and 6p per kWh plus ÂŁ100 or so for the gas standing charge.

So, well done Octopus, well done Daikin, it could have been better but pretty good really.

Sorry for the whinging :slight_smile:

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It seems very good to me, scop of 4,88 is not bad.
Please can you tell me your square space and flow temp. Also your insulation?
I am planning similar instalation here in Croatia and every data is valuable for me.

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I must agree with you Matt.

We like chasing the best, and there is always room for improvement. However, I am also very happy with my 16kW Altherma bibloc. I think it is well built, has millions of controls for us to geek over and modulates down quite well.

It is still oversize, full LWT control is not possible so Madoka needs to switch it off when it reaches 22.5ÂșC during the day or 20.5ÂșC at night.

Minimum LWT is set at 30ÂșC, with weather compensation and a -5ÂșC offset at night.

Over the last 12 months it has supplied 4953kWh of hot water (SCOP 3.5, tank at 50ÂșC), 14856kWh of heating (SCOP 4.91) and 8436kWh of cooling (SCOP 4.99).

I consider above values to be extremely good, and hardly worth the effort of trying to do better. It has saved us almost 2400 euro vs our old oil boiler over the last 12 months, plus given us cooling in the summer months. Granted, the installation was very expensive, we heavily overpaid, but hopefully it will save us money in the long run.

Hope it has a long life!

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Thanks for the update @matt-drummer.
We’re still in conversation with Octopus about possibly having our 9kW swapped for an 8kW. A few cold days where we hit the outdoor design temps rather reinforced that the 9kW is somewhat oversized as the house stayed at temp with a peak of about 5.5-6kW heat output, despite -2.6ÂșC outside. Seems a long way away from “9kW heat loss” :smile:

Currently waiting for a decision although getting O to review submitted data and accept that there’s a huge difference between real-world performance and what the calculations claim is an uphill battle.

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They are good figures!
I guess you have warmer or shorter winters than we do in the UK?
Also gets hotter hence you switching to AC / coolingđŸ„”

Do you have the hot water on Comfort/ 50C setting all the time?

When I had Comfort HW it worked fine with Madoka.
When I tried ECO HW it got overridden every time by the heating.
Going LWT / Madoka out of the loop it solved that.

Must be a bug that ECO HW can’t override heating even once you’ve set it to!
Wonder if anyone has raised it as such with Daikin?

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Hey,

I would say we have shorter and warmer winters than the UK, yes. We also usually have a bigger difference between day and night, which allows a bit of tinkering:

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Above is average data these past years.

I have the HW in re-heat mode, at 50ÂșC and with a hysteresis of 20 degrees. It does HW twice or 3 times a day, depending. I played at the start with schedules etc but it is too much of a hassle.

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