[Gazza77]

We renovated our terrace house and installed water underfloor heating. There are advantages and disadvantages to it, however I'd say it was worth it. We have a stone floor downstairs which is excellent at retaining the heat (the pipes themselves are laid in screed underneath), with pipes laid in aluminium plates upstairs, under a chipboard floor, with underlay and carpet underneath. This is not as effective as downstairs, however is still effective. We're part way through our loft conversion at present, and that will have an engineered wood floor, so it will be interesting to compare the effectiveness of that compared to carpet.

Advantages:

Constant heat across the room, rather than hotspots near a radiator.
Cost effective to run - our 2 bed terrace costs us about £63 a month in total for gas and leccy combined, and that includes the cost of running a dehumidifier and an optimate on constantly for 6 months of the year, which does make our leccy bill rocket over winter!
In a small house, no radiators means that you have more space for furniture, as you don't need to leave a wall spare with nothing against it.
Keeps the house warm, although obviously insulation is a key part of this.

Disadvantages:

Costs more to install.
Doesn't heat up quickly, so you need to plan when you have the heating on in advance, rather than just turning it on/up when you feel cold.

We also have a mulitfuel stove in the lounge as a secondary heat source, so if it doesn't feel as warm as we want, we can quickly get a fire going for a quick and cheap solution.