Operating costs of air-to-water heat pump, consumption and defrosting

How warm or cold was it in the house until last weekend?

My thoughts:

- the defrosting has also been a disaster for us since Tuesday - but that is due to physics and the special weather conditions
- the place was probably completely cooled down - so the high initial consumption is also normal
- everything else - such as whether there are any additional factors in the house or how the system is set up, etc. - we of course cannot assess...

In general, the last 4 days have also been the ones with the highest consumption since installation for us...

So the heat pump fits already, it modulates down to 1.7 kW, the smaller one would be 1.1-5, yes, that could have fit too, but I don't think it's completely oversized.. Just take a look at the menu in the indoor module (which one? EQ or compact?) and tell me heating curve, flow temperature, outside temp. The question is also, are you on the Zugspitze or rather in Freiburg...

Previously, there were only fan heaters in the building, so it wasn’t particularly warm. The de-icing has decreased somewhat today (approximately every 2 hours, just above 0°C during the day), but there has been no significant change in the immense power consumption. The indoor module is the Compact variant, the flow temperature is set to 26°C, and the system is located in the Greater Dresden area. I don’t fully understand the heating curve, how to query it, and how to interpret it.

The installer said today that this is because the room thermostats have not yet been installed, all valves are fully open (manually set), and therefore the system is running at full load. He set the target temperature (although I’m not aware of where the system gets this from if there are no room thermostats yet) and the heating stop parameter to 19°C; I lowered it to 17°C today after consulting with him. I’m curious to see how it looks tomorrow...

The supply temperature is set to 26°C

all valves are fully open (manually set) and the system is running at full load as a result.

26 degrees is very moderate – with that, the place will not really get warm at first. Full load would be 45-50 degrees. All valves open is already OK, because

the room thermostats are not yet installed

just means that all rooms are heated. Room thermostats only switch on or off, but do not regulate the amount of flow, unless one considers the options 0% or 100% as "regulating."

Can you read more on the display? Compressor frequency, supply/return temperatures, pump performance, or similar?
Defrosting every two hours is currently okay. Last night at -4 degrees here every 1.5 hours, during the day at around 0 degrees every three hours.

As long as you have not moved in, you should not make a fuss here. As long as craftsmen are coming and going, and doors and windows are left open, the consumption values cannot be trusted.