The most popular way to heat a room is via a gas fired boiler central heating system with wall hung radiators. This is still the cheapest was to heat your home when up and running but is it the most efficient? With wall hung rads, heat is concentrated from a single point, relying on convection to move the heat around the room. This means it’s more than likely one wall and your ceiling will be warmer than the rest of the room. The benefit is a running cost of 7p per hour based on a 30sq/m sized room.
Under floor heating does provide an even heat across the room and a wet system running off that gas fired boiler is certainly the most efficient and cost effective to run, but it is more expensive as well as intrusive to buy and install.
If you are renovating a room rather than building, an electric UFH system might be the answer. The benefit is a cheaper installation cost and minimal increase in floor height. If you are considering this, there are two options depending on the required use; taking the chill off floor tiles in the winter or using it as the main heating source for a room.
The first option would require a 100 kW/h system and depending on the size of the room and your energy supply rate, would as an example cost 24p per hour based on the same size room as above. However, this is only good for warming the floor, so you would still need another heat source, perhaps a traditional wall hung radiator. Both running together, would equate to 31p per hour.
If your electric UFH is the main source of heat, you will need a 150kW/h system and based on the same sized room, would cost 36p per hour to run.
You will need to apply your own supply rate whilst considering how insulated your home is and how warm you like it, so the above rates are for example only but does provide a good comparison.