Gas heating without solar thermal?

You don't have controlled residential ventilation with heat recovery? In which year did you build? How is the insulation, under the slab, walls, roof, windows?

Hello, we received a KW 70 standard house. Approximately 220m² total area, of which 170m² is living area including sloped ceilings. Heating is gas with a 300l water storage tank connected to the solar thermal system on the roof. (2 panels)

Since May I have not used any gas. The entire hot water production is currently done via the panels. During the transitional period, when the sun was shining, the underfloor heating was also supplied this way. We are now probably at an energy consumption of about 30kW/m² for gas consumption. I cannot say how this would look without the thermal system.

PS (however, I burned about 3RM of wood in the fireplace during winter, this energy amount must be added)

Sorry but what is controlled residential ventilation?