Vitocal 300 A - over a year in use. Now a few questions..

The hot water is around 45 degrees, what you can still do is set all the regulators in the rooms to 24-25 degrees and control the reduction via the heat pump, so that the temperature throughout the house settles at 21-22 degrees.

According to the heating consultant, legionella should not be a problem as the water rarely stands for a long time.

For which period exactly is the consumption? 2014 can also mean 2 years, but in any case, you are already in the second heating season. Then the value could already be okay. Did the heat pump also heat the screed?
1900h per year is okay, the starts as well, i.e. it seems like the device is not cycling excessively.

The heating system went into operation in September 2014. So now it’s the second winter. The screed was not heated along - they had a different device for that.

I took some notes during the year. Unfortunately a bit neglected.... Attached is a screenshot

So the information on the screenshot is a) incomplete b) not easy to assess without a diagram (fluctuating periods, etc.). Additionally, the fragmented temperature data is not very meaningful.

Here is a comparison example from me. Among other things, I log the consumption (not just the total, but the course of each day) of the heat pump and the temperature, and at the end of each day I calculate the total consumption and the heating degree days. The heating degree days is the average temperature difference between outside and inside over the entire day. Outside I measure at a wind- and sun-protected spot near ground level (so it could be tendentially warmer there in winter, colder in summer than e.g. on the house wall at some height), inside in a room with typical temperature. The diagram lacks axis labels in an unscientific way: the x-axis represents the past days since 1.10.2015, the y-axis kWh for electricity consumption, °C for heating degree days. The electricity consumption includes, as in your case, domestic hot water preparation (basically a small offset to the curve compared to heating operation).



What you can also see very well besides the consumption is what the heating costs depend on during the year: quite exactly on the daily/annual heating degree days. This is due to the linearity of heat losses. There are certainly some exceptional days, e.g. cooler days with lots of sun.
If you have both the annual heating degree days and the consumption for some days, you can very well compare your costs/consumption at different temperatures, as well as heating load at certain temperatures, or the actual insulation level of the building compared to standard calculations, etc. (if you, of course, take the heat generated, not the consumption in kWh). Very nice for comparison. Maybe this helps you and your ideas for optimization/determining the actual status of your system.

Unfortunately, I cannot log with my heat pump – I have to write everything down manually and unfortunately I forget. In the last 4 days, I have consumed about 21 kWh per day. During the day it is -4 degrees and at night -10 degrees. I will try to write it down every day.

unfortunately, I cannot log data from my heat pump – I have to write everything down manually and unfortunately I forget For the last 4 days, I have consumed about 21 kWh per day. During the day it is -4 degrees and at night -10 degrees here. I will try to write it down every day.

The overall information, especially about the house, is still too sparse to really make a comparison. Otherwise, I roughly estimate your degree day value with your figures at 28 degrees. At this average of -7 degrees, your (very good) heat pump (depending on the model, which exactly??, roughly read from the COP diagram) has a COP of around 3 (if the slope of the heating curve is about 0.4 and the temperature is set to 21 degrees -> flow temperature around 30°). A few kWh for hot water, and then you have produced about 50 kWh of heat per day for the house. This corresponds on average to a heating load of 2.1 kW. I would say that this is a well-acceptable value for the square meter size and temperature. At -15°C that would correspond to 2.7 kW heating load. If your numbers are correct and I (after today’s particularly exhausting workday) haven’t calculated complete nonsense; but even 20% more would still be good. In summary, this means that the little house was probably insulated properly (also in execution, not just in calculation), and the consumption is correspondingly low. Lifetime / number of starts is not much of a problem with modern heat pumps (at least not for the compressor). They usually have current limiters etc. for compressor start-up, and a runtime of 2000 hours per year is basically normal. With ground-source heat pumps, the borehole is also designed for these runtimes. Also, you have on average 2 hours runtime per start, so not so little. Some here have completely different problems (5-15 minutes e.g.). From my “layman’s view,” this looks like a green area.

then I am relatively relieved. Since I am interested in it, I ordered the Optolink USB Adapter and will get it running on a Raspberry PI. Maybe then I can provide more accurate values.