Gas heating new building - Is solar thermal necessary for hot water?

Controlled residential ventilation with heat recovery is often not sufficient and only works with additional measures... A token solar system for hot water is the usual and simplest way Heating support through solar thermal is rubbish... In winter you get 0, nothing from it and when the sun shines you don't need any more.

We are currently facing the problem ourselves:

Gas condensing boiler + central controlled ventilation with heat recovery.
The controlled ventilation is not sufficient, we also need solar for hot water. We are currently calculating how it would look with a photovoltaic system. Plus an electric heating element in the hot water tank.

I am firmly convinced that the nonsense with solar for hot water will never pay off. That is why I will try with all my might to avoid it.

Whether nonsense or not. We are installing a gas condensing boiler plus 5.6 sqm of solar panels for hot water preparation, plastered monolithically with Ytong. To comply with the Energy Saving Ordinance, this is sufficient; windows are better than 1. It is not sufficient for KFW 55. We have not purchased controlled residential ventilation. Karsten

I do not understand the last post. So ST is generally sufficient for hot water or does the heating also need to be supported?

As I said, we are planning with a gas heating system.

Yes, to comply with the Energy Saving Ordinance, a solar thermal system is sufficient.

Best regards in short

Thank you. Finally, getting down to business. But how do you know that? I searched on the internet and couldn’t find anything....

And one of the two heating engineers only wants to sell me the [ST mit Heizung]. He refers to the Energy Saving Ordinance.

He just wants to make money... or his remaining house concept is so bad that nothing else is enough...

You have real experience here and real houses that have been built or are still under construction or will be built soon...

I am firmly convinced that the nonsense with solar for hot water never pays off.

Certainly... but it prolongs the operating life of the boiler and in summer you have plenty of hot water... you can also fill your pool with it...

...and the most important thing is that it is enough to comply with the energy saving ordinance... ergo you don't have to add more insulation or perform other tricks that also don't pay off.