Floor plan planning shortly before submitting the building application

Heating load calculation is now available. However, it apparently comes from a stage where the 41m³ had not yet been reduced. Is the reduction significant enough to warrant a new calculation, or does it not really make a difference overall?

Although I suspect it will have to be redone anyway, since the building authority also requires this proof.

Oh just saw your attachments. Those are data from the [Geologischen Dienst]. It really looks poor, you can forget about the probe there. Even if you weren't limited to 30m depth, that would be a disproportionately deep and therefore expensive drilling.

The specialist company says that surface collectors are an alternative. Apparently, geothermal energy is sufficient for these. But I don’t have a good feeling about it. The construction contractor also said that he has never experienced a project where it was actually installed in the end.

At the moment, many things speak in favor of the gas heating system. Allegedly, according to the Energy Saving Ordinance 2016, one can do without the actually mandatory solar component if a certain percentage of biogas is purchased and this covers the ecological aspect. But how is it supposed to be proven in the long term that tariffs with the corresponding biogas share are always booked? Sending the billing statement to the authorities somewhere every year. If that really works, we prefer it 1,000 times over an air heat pump or surface collectors.

How much would the price difference be between geothermal energy and gas for the [GU]?

Is controlled residential ventilation planned?

But how do you want to prove on a long-term basis that you are always purchasing tariffs with the corresponding biogas share? Sending your bill somewhere to the authorities every year. If that actually works, we prefer that 1,000 times to an air heat pump or flat collectors.

To my knowledge, that doesn't work. Biogas actually has to flow through the pipeline. You can only achieve that if the neighboring farmer has a biogas plant and you can connect to it, to put it bluntly. Controlled residential ventilation would be appropriate here. More expensive than solar thermal, but with benefits.

Yes, controlled residential ventilation is planned.

Gas would be €5,214 cheaper. Even with the solar collector system. What it costs without solar, provided you get the biogas option, I would have to inquire about.

EDIT: I think the biogas option won't work.

"Only if the biogas is produced in close proximity, that is, in a biogas plant next door, is the biogas rated with a PEF of 0.5. Since biomethane is usually delivered to the customer via the regular natural gas network, it therefore has no influence on the calculation of the primary energy demand within the framework of the Energy Saving Ordinance."