We have an opportunity to buy a house from 1997. Our concern is that it has no underfloor heating. The first floor is about 65 sq ft and the second floor. The bathroom is about 12 sq ft. We wanted to remodel the bathroom and guest bathroom anyway. And on the first floor, I'd probably remove the laminate and tile myself. How much would such an upgrade cost?
I don't think anyone here can seriously answer this question since no one knows what the substance is or the construction of the floor.
Does it have a wallboard? Are there floorboards? Is there insulation under the screed? Only a specialized company can tell you that.
If there is a screed, there is the possibility of milling sections of the floor with underfloor heating for pipes. But this will not be cheap.
The year it was built 1997 is fairly recent. you can assume there is already soundproofing and screed. The easiest way is to remove the old screed, it is not a big problem.
Lay a new cement screed, in which to lay the pipes. An alternative would be to take the old radiator pipes to the floor, connect the heat exchanger, and then connect the compact control station to the heat exchanger and then distribute from there.This should be done once per floor, so you do not need to change anything in the old heating system.
Of course, these are all just assumptions, since we don't know what the real situation is.