Choice of heating for old building renovation with low ceiling

Good morning,

we are currently looking more and more at old buildings for renovation... often we encounter ceiling heights of ~2.4-2.7m. I understand that in case of doubt a decision has to be made on the specific property, but I would like to better understand the sensible options.

The goal for the new heating system is clearly an air-to-water heat pump, although we are basically open to other options.

For cost reasons and because we want to do a lot ourselves, the challenge of "partial insulation" comes into play – I currently assume that in the first step we will only insulate the roof and the walls will be added from the outside later (at least that is the wish, I am at least partly aware of the implications, see below).

We would prefer underfloor heating, but I see the problem with all the door thresholds and accordingly also door frames that would have to be enlarged, possibly replacing lintels, ... are there systems with very low construction height? The screed also stores a lot of thermal energy, so I rather suspect nothing sensible?

Another alternative would be ceiling heating, but I have similar concerns about the overall room height and I have read several times that ceiling heating is supposed to feel unpleasant in low rooms. Does anyone have experience with this?

Wall heating is of course bad without wall insulation and I do not want to install it on the inside of the rooms – but it would be an interesting option, it would then mean that the exterior wall insulation would have to be applied directly.

Last option – low temperature radiators. I have absolutely no idea how good or bad this is compared to surface heating (probably noticeably worse?). Of course, you have the radiators in the room. On the other hand, probably the cheapest solution among those mentioned.

Furthermore, presumably the problem that with different insulation methods over time, the air-to-water heat pump actually would have to be designed differently? Alternatively, wood pellets and radiators would be an option, but definitely not our preference.

Has anyone recently thought about similar things and maybe is a few steps further? Are there other options I am forgetting?

Best regards

Edited: Windows would be replaced directly, as well as roller shutter boxes.

So anything from 250 onwards is not a low ceiling for me ;) We have 240 and are removing the screed and then installing underfloor heating with a heat pump. However, we are also completely renovating now, including the roof, [Photovoltaik] and external insulation.

I would do the external insulation right away. If you do it later, you will have an oversized heat pump after insulating, which should be avoided.

Thanks to both of you!

So one of the houses we currently have in sight only has 2.4m from the top edge of the beam to the bottom edge of the roof floor beam on the upper floor. Every centimeter hurts the feeling of space. Since there is no screed so far, but mostly only battens on the beams and then the floor directly on top, there is unfortunately not much room for maneuver.

Yes... maybe we have to come to terms with insulating completely right away, unfortunately not so easy with a very intricate facade and a partially converted barn.

The upper floor is not so important in terms of floor insulation. The heat then also goes into the living space. On the ground floor, a renovation solution with maximum insulation is WEDI boards (or other construction boards of the same kind). You can use them as a screed replacement and directly mill cable paths. You are then only limited to tiles as the floor covering. A 10 cm installation distance is also possible there. We did it that way in the bathroom after approval from WEDI and it is also stated on the manufacturer's site. You basically have hardly any storage mass in the floor, so you should rather have solid walls without internal insulation.

Is it possible to open the roof a little bit in the upstairs? We lifted the suspended ceiling and now we have 280cm there :) But that only worked because there was nothing else except the roof there.