Design heating system

Hello everyone,

My parents-in-law live and are building a house in Poland, 80km northeast of Warsaw. The temperatures there easily reach -20°C in winter. At night, it is sometimes even colder.

Now they want to build it as energy-efficiently as possible. It will be thoroughly insulated. However, I am unsure about the heating system.

A pellet stove will be installed. Additionally, a solar system is desired. As the icing on the cake, I am thinking of a fireplace that heats water through the combustion heat (this is optional, though).

After talking to the heating installer there, I am very confused. I thought that the solar system could be used for both hot water preparation and heating. However, the heating installer claims that it can only be used for hot water preparation.

What is your opinion on this? Is there a way to do it as I originally imagined?

Best regards
mission2010

Now, there are different concepts... and heating systems are as common as sand on the sea... you just have to decide for yourself exactly what you want... however, a water-bearing fireplace is usually uneconomical...

OK. Let's leave the fireplace aside for now. The question is, can the solar system also heat the house? At least partially, so that the pellet stove has to provide less than 100% of the required heating capacity? Or can the solar energy only be used for hot water preparation?

Except for the bedrooms, underfloor heating is to be installed in all rooms. In the other rooms, I am not sure whether a wall heating system or conventional radiators will be installed. It would be great if you could share your experiences with wall heating.

Thanks and best regards
mission2010

....Now they want to build it as energy-efficiently as possible. It will be thoroughly insulated. However, I am uncertain about the heating system...

What does building as energy-efficiently as possible mean? What is the actual demand (power, energy) for heating and hot water? What actual energy contribution can the solar system (hot water and/or heating support) provide?

...Is there a way to do it as I originally envisioned?

Technically, almost everything is possible, but whether it actually makes economic sense is a completely different matter!

Best regards

What does building as energy-efficiently as possible mean? What is the actual demand (power, energy) for heating and hot water?

How can I calculate these demands? Can you recommend an online calculator?

I have the following numbers:

[*]Floor area
[*]Room height
[*]Thermal conductivity of the walls including insulation
[*]Thermal conductivity of the windows
[*]Window size and number of windows
[*]I can calculate the exterior wall area

Do I need anything else?

Thanks and best regards!

the only solution is to visit a heating specialist...