Small house on large towel plot

You plan, for example, a really expensive basement for hobbies, an unnecessary fireplace, indoor sauna, etc.. For me, the interior of the house, meaning the living comfort, would have absolute priority (see for example air conditioning, controlled residential ventilation...)

Fireplace and sauna in the bathroom (and conditionally also the basement) are pure living comfort.

That will change, and especially also the needs of the elderly, so one should take a close look.

Absolutely right, I have been trying to extrapolate that for two years. It is foreseeable that in a few years it will be just the two of us in the house, apart from hopefully frequent visits.

... have you ever had a fireplace in an absolutely airtight, well-insulated house with underfloor heating at the same time?

No, but my brother has. Since he got a better fireplace, his underfloor heating only runs in winter. Heating costs halved.

um....I particularly like the fireplace and use it well, namely for heating.

Glad we agree on that. Heating in transitional periods and when the heat pump is struggling is the plan. Controlled residential ventilation is not canceled, it is just not a must but would be nice to have. It's not like I definitely want a heat pump. Actually, I don't like central heat pumps. Apparently, I will have to want one.

In addition, there is the rather uncommon situation that you will soon be 3 adults. Should all 3 permanently sleep upstairs or wouldn’t it be worth considering that the 17-year-old perhaps lives on the ground floor with an ensuite bathroom?

I would need more privacy inside the house and I currently don’t see that.

Worth considering, yes, which teenager wouldn’t be thrilled. But we wouldn’t be. We are not a hotel with an attached restaurant. But we also do not expect secret visitor traffic in the teenager’s room.

A sauna IN the house is nice, but for a fraction of the cost, it also works wonderfully outside, you have the property for it.

I dare to doubt that. A reasonably stable and weatherproof little house does not come for free. The interior is the same anyway.

Or: scratch the really expensive basement and build a truly spacious garden house on the ground floor (you have the space and don’t have to climb stairs when you get older).

I don’t see a garden house as a sensible option in terms of significant cost savings. Or did you mean a bungalow?
Not least thanks to good arguments from you and others, I will take a closer look at the no-basement version, with and without an upper floor. Let’s see how much savings will be eaten up by the then larger footprint requirement.

What we underestimated: such a heat pump with underfloor heating only runs efficiently if it runs continuously - in other words, the temperature in the house is permanently in the comfort zone. If we now heat the stove, we have >27°C in the living room within a very short time. Also nice sometimes, but of course not a permanent state that is pleasant... As a result, we hardly use the wood stove in winter. On the other hand, it is great in the transitional period.

Thank you very much for the experiences. That is exactly my expectation of a stove. The water circuit is not even "nice to have" but more like "if it makes sense". And if it doesn’t make sense, then simply not. Wood as a primary energy source would be possible for a few years. But not future-proof, also politically.

These additional reasons would deter me from the underfloor heating or the fireplace, also because finances are tight elsewhere

Thank you for your experiences. Really good input from you. I am not an expert in modern heating technologies. I also don't personally know anyone who has a controlled residential ventilation system. Here in the forum, you practically only hear positive things about controlled residential ventilation. If you live in a rural area, a balcony door or window is probably open quite often. Of course, I wonder whether the controlled residential ventilation still offers enough advantages in such cases to justify the acquisition and operating costs.

From my point of view, that's the big disadvantage of underfloor heating; you can't just quickly adjust it. We like it 20/21 degrees during the day when you move around a lot. That's how the underfloor heating is set. But in the evening, that's too cold for us.

However, I would not want to heat exclusively with the fireplace. On the one hand, because we are often away for a long time in winter and then my son would have to heat additionally. On the other hand, I wouldn't like the obligation behind it. We also considered integrating a water-bearing one but abandoned that.

Thank you also for your personal experiences. I suspect something similar for us. As already said, the water circulation is on the wish list just above the underground garage.

Thanks also to you for your personal experiences.
I suspect something similar for us.
As already said, the water management is slightly higher on the wish list than the underground parking garage.

An underground parking garage would be a no-go for me. Steep driveway up and down, never voluntarily.
I would also build a cellar if I had the appropriate hobbies and financial means. A garden house is never a reasonable substitute for that in Germany for at least 6 months.
We also do not have a controlled residential ventilation system. It has been working flawlessly for almost 4 years now.
Although I would ALWAYS build a bungalow if the plot allows it. For you, actually with a somewhat separated part for the teenager. That can later become a holiday apartment, guest apartment, apartment for the caregiver… as needed.