New heating system with hot water preparation?!

Good morning,

after a long search, we have found a house. It has a gas heating system installed (1997) that is only responsible for heating. For hot water, there is a flow heater installed. Of course, the energy certificate is not very impressive. The house was completely renovated in 2013 and has about 145m² living space. Suggestions in the energy certificate:

[*]new gas heating with condensing boiler
[*]for hot water: solar combined with gas heating with condensing boiler

I have already been to 2 heating companies near me. They don’t think much of solar.. The suggestions were to install a storage tank and that's it (60 L).

Do you have any other suggestions or ideas for hot water preparation?

Thanks in advance

Regards

Steven

I would also skip solar thermal. The money would be poorly invested. An ecological alternative would still be a domestic water heat pump. Keep in mind that water heating requires only a small portion of the energy compared to heating, and elaborate measures hardly pay off. Gas or, for few people, also instant water heaters are economical.

If gas for heating is decided, I would also use it for the domestic hot water, plus as much photovoltaic on the roof as there is space.

Photovoltaics pay off on their own thanks to subsidies, independent of the heating system, and more can be done with electricity than with some heat from the roof for hot water. For example, a domestic water heat pump can be operated most of the year with self-generated electricity. Still, I would probably stick with gas for hot water.

Since the house has one room with underfloor heating (bathroom) and the rest has normal radiators, it will be difficult with an air-water heat pump, right?

There is also a fireplace in the living room.

Ok, then I will take a look there! or stay.

Thanks =)

Yes, unfortunately it doesn't make sense with a heat pump like that. The efficiency depends on the "worst" room. Living room with mini radiators and large windows means high flow temperature, for example. Low-temperature radiators with active fans might be an option, but no idea what that costs. With a heat pump, the planning must be very good, every room has to be calculated.

In an unrenovated old building, an air-to-water heat pump for heating and hot water is 99% nonsense. A pure domestic hot water heat pump with photovoltaic electricity could be economically viable, but that very much depends on the framework conditions. A professional needs to take a look and run the calculations.

However, if your boiler needs or is supposed to be replaced soon anyway, and your entire remaining infrastructure is already designed for gas, then it would be stupid not to use it. Gas is not that bad, the condensing boilers are very good and efficient. So why not use it!

There might still be old cast iron radiators hidden somewhere, where it makes energy and also aesthetic sense to replace them with modern radiators. The money is better invested there than in an air-to-water heat pump.

Economically, it is probably most sensible to leave everything as it is. In 1997, condensing technology was probably already installed; if the heating system basically works, replacing it just for the hot water is not worth it. Additionally, pipes would need to be laid, meaning walls and possibly floors would have to be opened. Are those supposed to be done anyway?