The house costs €152,000 gross without any extras and has the Standard 85. In the wishes, the surcharge KFW 70 (triple glazing and floor insulation) with €4,500 is included. According to the standard, we would have a normal gas condensing boiler with radiators. The €8,000 is the extra cost for a complete underfloor heating system. According to an independent building expert, this is supposed to have the advantage that we only need to heat with about 35 degrees when we heat only with underfloor heating.
I have actually always slept with the window open, all year round. The waterbed also makes it easier for me not to be cold at night. However, I have concerns that the ventilation in the bedroom cannot replace the fresh air of an open window.
The developer is a reputable company that has existed for 30 years and carries out about 150 constructions annually. They have their own energy consultant who will calculate the house on the computer and can tell us whether the measures are sufficient for KFW 55.