Attic expansion - how to supply hot water?

Hello,
thank you for the answers.

As I said, we would only use the instantaneous water heater for the two washbasins, so such a small instantaneous water heater with 5.7 kW should be sufficient. As far as I know, you also do not have to report anything to the supplier for that. So it should be a device up to 200€. We only need one device, any slightly warmed water is more pleasant than cold water. Therefore, it would also not be suitable for the bathtub.

The idea with the pump, which you can connect for example to the bathroom light switch, is not so wrong.

Tomorrow a plumber is coming again. Let's see what he thinks about the matter.

Best regards from
Babenhausen

write how it continues!

The plumber (who also carries out the regular heating maintenance) took just under 90 minutes this morning but arrived at 7:45 instead of 7:30. However, it was also about the type of heating for this room (underfloor heating like on the ground floor or radiators like in the basement).

There is already a circulation pipe with a pump in the house, only it had been turned off the whole time. They have now set it to 3 minutes running and 7 minutes off.

Since currently only a 50mm pipe leads from the attic to the sewer and we actually need a thicker pipe for the toilet and also for the bathtub (over 3m length), he would completely renew the around 20-year-old pipes that come from the basement and connect them to the existing circulation.

Over the weekend I am supposed to check whether the wastewater pipe goes straight down into the main pipe or if it was routed via a detour through the suspended ceiling and the built-in wall of the guest toilet.

I am getting to know my parents-in-law’s house better and better.