Photovoltaics for hot water

Why are you worrying so much about whether photovoltaics or solar thermal pay off when you are already spending several thousand euros extra to install a stove with heating water heating in addition to the gas condensing boiler?

This is not about efficiency and cost-effectiveness, is it?!

You can also achieve KfW70 without solar thermal, but if that doesn't work despite the aforementioned stove, then in my opinion you should reconsider the whole concept (insulation?).

If you don’t want insulation suitable for KfW70, I would rather stay away from KfW altogether, then it won’t be such a “hack job”.

Ok, the post is somewhat old. But my question regarding this:
We achieve KfW 55 standard on the building envelope and lose so much through "window ventilation" that we don’t even manage KfW 70. Now I noticed that in the energy saving ordinance calculation, at the end under final energy by energy sources, the hydronic wood stove is only listed under heating with 6.5 kWh. Can someone tell me why it shows 0.0 for hot water??

Which water does the wood stove heat? Heating and hot water are different circuits and independent of each other.

I could imagine that the stove only heats the heating water buffer.

We still have instantaneous water heaters and also photovoltaics. Our pellet boiler is supposed to provide heating only, no hot water. The hot water is still to be produced with electricity; however, one of the instantaneous water heaters will be replaced with a domestic hot water heat pump (80 L capacity), which will then be powered by photovoltaic electricity. This is said to save a lot, but then warm water is constantly kept available, which is not necessary with an instantaneous water heater. Since we currently have an annual electricity consumption of 3000 kWh INCLUDING hot water (!!!), I don't really believe in big savings. The instantaneous water heaters are really very economical, as you can see from our electricity consumption; however, we do not take baths either. Of the 3000 kWh, we only had to buy 1800 kWh last year; the rest was provided by the photovoltaic system. However, one must not overlook that the photovoltaic system produces almost nothing in winter. There are between 0 and 2 kWh per day in December (total capacity max. 7200 watts), which is not enough for big leaps.

How much photovoltaic do you have on the roof? Pure south-facing roof?

Regards
Markus

So our plumber first offered a gas boiler with a 100l hot water tank. But then we said that we would have a water-bearing stove, and he said that the hot water tank would be omitted because we are getting a buffer tank. I thought that heating and hot water would be supplied there. By the way, he was also surprised that the stove shows 0.0 for hot water.

So our plumber first offered a gas boiler with a 100l hot water storage tank. But then we said that we would install a water-bearing stove, and he then said that the hot water storage tank would be omitted because we are getting a buffer storage tank. I thought that both heating and hot water would be supplied there. By the way, he was also surprised that the stove shows 0.0 for hot water.