Advanced Zoning Ability Leads To Efficiency Gains
Electric in floor heating tends to be controlled on a room-by-room basis (rather than one central thermostat for central heating). This creates an ideal situation for heating efficiency. Warmup thermostats can be programmed to only heat rooms when it is required. Energy isn't wasted heating rooms that don't require heating at that time. Also, this leads to a higher comfort level as rooms which require less heating can have their own temperature settings which means they won't be overheated or under heated.
The difference in running costs between oil or gas fired heating and radiant floor heating systems will vary according to the thermal characteristics of your individual house, the age and efficiency of your traditional heating system, 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, a 10-15% energy saving should be possible using insulated in floor heating systems when compared to conventional electric heating.