Gas or heat pump in a KfW55 house

The brine heat pump manages it effortlessly. For us, 500 liters at 48 degrees (large family, fresh water station).

45°C for 15-20 minutes is enough for me.. But what about Legionella? They also like it nice and cozy warm *g*

45°C for 15-20 minutes are enough for me.. But what about legionella? They also like it nice and warm *g*

It doesn't matter with our storage tank, since it is a fresh water station. That means the water in the (separate) tank heats fresh water via plate heat exchangers. The water in the tank therefore never comes into contact with the potable water.

The brine heat pump manages it effortlessly. For us, 500 liters at 48 degrees (large family, fresh water station).

But that is absolutely sufficient on its own. You can already slightly burn your skin at 48 degrees.

When I, a person who easily feels cold, see on my phone that my hot water tank is at 37-38 degrees in the upper part, I can still easily take a 20-minute shower with it.

I save a lot on hot water in winter (Swabian!, meaning €-cost-effectively fixed), so the temperature in the tank can drop quite a bit. Hot water is made once a day, 55 degrees. That has to be enough. For an impromptu full bath (large tub), there is the great function "One-time load"......

Every 4 weeks, however, I do a thermal disinfection. To make life difficult for legionella. It costs 1.5 cubic meters of gas, about 16kWh; 80 degrees in the boiler and then flushing all hot water pipes with it.. Not necessary in summer, since the amusing solar system heats the boiler anyway so much that you could supply steam to locomotives....

I guess, without having experience: With a heat pump, you also have to do the thermal disinfection, then via the heating rod. Because permanently 40-48 degrees – there is really a slight risk of legionella.

Best regards
Thorsten

We were told that in single-family houses this can mostly be neglected; especially if the tanks are under 300 l. Opinions on legionella seem to differ...

It also depends on the exchange rate. If it is a small tank, the entire water is basically changed every day, so that no significant proliferation takes place.