I haven't used my pool yet, so I can't comment on power consumption. Sensibly, I will only use it during the summer months. This was also recommended to me by a colleague who has been using it for 3 years.

just use it in summer

The pool heats perfectly at below 0 degrees. My heating has been running permanently since October and I have set the thermostat to 40 degrees, i.e. max, because as soon as you cover the pool and set the bubbler, it loses about 4 degrees in 30 minutes of use. A whirlpool is a luxury and if you have to reckon with electricity costs, you'd better leave it alone. It is not cheap, but it is dignified and relaxing.

2°/h is about right if it is not too cold. Your example (18 h) would therefore mean that it has to be heated up from 2° to 38°. That would be just under ten francs for one heating. For the whole weekend it could be 25 francs if you use the pool extensively. That is, when the cover is open. However, we mothballed the part in September. Even at an outside temperature of 10°, the heating had trouble maintaining the 38° during use. And in view of the announced power shortage, we had a guilty conscience. I can't say whether the 38° can be reached at all in winter temperatures, I have my doubts. By the way, the instructions say that the pool must not be outside when it is freezing. The pump is certainly not frost-proof. It would have to run constantly.

Also der 6 personen pool