Hi
Underfloor heating can be very effective, your initial choice is wet or electric. It works very well when installed as part of a new floor because you have the depth and can have good insulation boards onto which it can be layed plus a good 75mm of screed on top which acts like a large thermal mass. Takes time to warm up but then it just maintains the set temperature. With an existing floor you don't have the depth but there are systems designed for such situations and you need to be aware of your final covering, ie tiles or wood etc.
With many new builds since the nineties many floors are way off level and in this case if doing a major refurb you could decide to raise the floor height to level and fit underfloor heating as well. If your house has lino then this can be a sign of unlevel floors. In my current home built in the nineties the utility room floor had a central high spot that fell away in all directions, needed to be raised 30mm in the doorway area and about 20mm in other areas so it could be tiled, the tiler said he could not tile it because the depth of tile adhesive would be to much. This now means my kitchen floor is lower and so will be having underfloor heating, a single loop wet system.
