The Concept & Advantages of Underfloor Heating
Underfloor heating uses a radiant heat design to gently heat the room from the bottom up. Using Warmup Undertile Heating has two main advantages:

1) Vertical Heat Stratification:
Traditional systems heat from the top down and have a tendency to over-heat your head, leading to stuffiness. The heat is concentrated into relatively small areas (e.g. a radiator) and the heaters heat the air next to them.

The air then rises up the wall, along the ceiling into the centre of the room. When it reaches the centre of the room, it cools slightly, and then descends towards the floor.

To get warmer feet, you may need to overheat the head; as the feet naturally act as our body's 'thermostat' warm feet generally means we feel comfortable. The result is a warm head and cool feet.

Underfloor heating (AKA in-floor heating) heats the whole floor area resulting in the opposite vertical heat stratification - warm feet and a cool head. The vertical heat stratification generated by underfloor heating suits our body's natural requirements. We tend to emit a high proportion of our body's heat through our head, so it is warm anyway. On the other hand, our feet are at the extremities of our body, so need a bit more heat

2) Radiant Heat: The most comfortable form of heat.
Undertile heating spreads the heat over the entire floor area resulting in about half the heat being emitted as low temperature radiant heat. This gentle source of warmth reduces the heat loss from our bodies without overheating the surrounding air.

Radiant heat is considered the most comfortable form of heat. It gently and evenly warms us in the same way as the sun; it mimics that the type of warmth we associate with a perfect summer's day. Warm, but not stuffy.

Radiant Heating Efficiency - Is underfloor heating efficient?
There is a lot of confusion as to the extent of the energy saving abilities of underfloor heating (also called radiant floor heating). Results from various studies put the energy consumption of radiant floor heating anywhere between 52% less and 10% more than conventional heating systems. The confusion is caused by the extent of the reduction in ambient air temperature.

With radiant heating systems, approximately half the energy is emitted into the room as low temperature radiant heat. This process is very efficient as it provides a lower ambient air temperature allowing you to feel warmer at a lower temperature because the radiant heat is lowering the heat loss from your body. However, you will not fully benefit from this energy savings, if you overheat the room to maintain the ambient air temperature you are used to with conventional heating.

Energy savings vary depending on the insulation, usage patterns and personal requirements of the occupants. Other factors to bear in mind include the cost of the power source.
That said, the conversion of oil and natural gas to heat is far less efficient than electricity due to heat through the venting of the boiler.

Electric heating tends to be controlled on a room-by-room basis (rather than one central thermostat for central heating). The difference in running costs between oil or gas fired heating and radiant systems will vary according to the thermal characteristics of your individual house, the age and efficiency of your boiler and radiators, your usage pattern, the control systems implemented and your particular gas and electricity tariff.

The many variables make it impossible to provide a reliable rule of thumb.

As a general principle with Warmup a 10-15% energy saving should be possible using insulated undertile heating when compared to conventional electric heating.