Auxiliary heating, hot water, granny flat

Hello everyone,

we are about to complete our small basement granny flat.
For the granny flat, we do not have a water circulation system, which results in the hot water supply (especially after very long standstill) taking almost 20s - 30s.
The pipes are surface-mounted (thus accessible), so I am looking for a way to keep the water at an "comfortable" temperature (approx. 35-40°C).
The pipe is approx. 10m of surface-mounted pipe with a subsequent T-connection to the bathroom (another 4m) and kitchen (another 3m). The 4m and 3m are, of course, no longer optimizable, but there is still a chance with the 10m.

Are there any ideas? e.g. [Begleitheizung]

Thank you very much and best regards

There are these mini inline heaters, we have them distributed all over the workplace. It does not get hot but lukewarm. But isn't the pipe insulated?

I would avoid a pipe tracing heating system, as I see risks of unintentional legionella growth if the standing water is only kept lukewarm. Especially if the taps might not be used daily.

The simplest solution is the one recommended by tomtom79 – you need a so-called "solar-compatible" instantaneous water heater. Other solutions would be: smaller pipe diameter to reduce the amount of water in the pipes combined with better insulation, if the parameters can still be changed – but that doesn’t seem to be the case based on your description.

The Drinking Water Ordinance stipulates that the amount of water in the hot water pipe between the heat generator and the furthest tap must not exceed 3 liters – otherwise a circulation pipe must be installed, or an annual inspection must be carried out (warning, simplified by me, best to look at the entire ordinance).

Especially for rarely used taps, installing a circulation system would be an extreme waste of energy! Good that there isn't one! Trace heating or especially cooling (beer trace cooling) exists for beverage lines in gastronomy

A small under-counter device (or apartment station) would probably help. Legionella prefer certain temperatures. Please take the contribution from seriously.