ᐅ New Gas Heating System for a New Build – Is Solar Thermal Needed for Domestic Hot Water?

Controlled residential ventilation with heat recovery is often not sufficient on its own and requires additional measures… A basic solar thermal system for domestic hot water is the common and simplest solution.

Using solar thermal for heating support is inefficient… In winter, it provides almost no benefit, and when the sun is shining, heating is usually not needed anymore.

We are currently facing the following issue:

Gas condensing boiler combined with a centralized mechanical ventilation system with heat recovery.
The mechanical ventilation alone is not sufficient; we also need solar for domestic hot water. We are currently calculating how this would look with a photovoltaic system, combined with an electric heating element in the hot water tank.

I firmly believe that solar for domestic hot water will never be cost-effective, which is why I will do everything possible to avoid it.

Whether this makes sense or not: we are installing a gas condensing boiler plus 5.6 sqm (60 sq ft) of solar panels for hot water preparation, with monolithic Ytong blocks plastered. To meet the energy saving regulations (EnEV), this is sufficient; the windows are better than standard. It is not enough for KfW 55 certification. We did not purchase a mechanical ventilation system with heat recovery. Karsten

Marchonisch schrieb:
I don’t understand the last post. So, is solar thermal generally sufficient for domestic hot water, or does it also need to support the heating system?

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

Yes, to meet energy saving regulations, a solar thermal system is sufficient.

Best regards in brief

Thank you. Finally, some concrete action. But how do you know this? I searched online and couldn’t find any information....

And one of the two heating installers wants to sell me ONLY the timber frame with heating. He refers to the Energy Saving Ordinance.

He just wants to make money... or his remaining house concept is so poor that it simply isn’t enough otherwise...

Here you have real experiences and real houses that have been built, are under construction, or will soon be built...

matte1987 schrieb:
I’m firmly convinced that the nonsense about solar for domestic hot water never pays off.

That’s certainly true... but it extends the service life of the boiler, and in summer you have plenty of hot water... you can even use it to fill your pool...

…and most importantly, it’s enough to comply with the energy saving regulations (energy efficiency standards), meaning you don’t have to add more insulation or perform other tricks that also don’t pay off.