Which KFW standard and which technology in new construction

110 Bunga without circulation works well. Really.

Circulation is a must for a certain level of comfort. I would definitely not leave it out, waiting for warm water is extremely annoying.

No circulation pump for 190 sqm. However, the main bathroom is directly above the building services. The hot water arrives very quickly in our bathrooms and doesn’t freeze up like in the old apartment. In the kitchen it takes a bit longer, which doesn’t matter since the sink is large.

Is the KFW loan still interesting at all?
Do you want to sell the house in the next 10-15 years?
If both are no
I would take gas and controlled residential ventilation now
Later maybe use solar or photovoltaics and a heat pump.

KFW 55 is only an emergency solution if anything, we actually prefer funding through the ISB Bank Rheinland-Pfalz...

Selling only comes to mind if it is necessary for health reasons. In principle, the plan is to stay in the house as long as we are carried out feet first by the undertaker.

We would provide for a provision/empty conduits for a later solar or photovoltaic system.

Or then later when the gas condensing boiler is old enough or broken, then switch to a heat pump. They surely will not get more expensive and inefficient over time... it might also still be subsidized.