Floor heating guide
How to run floor heating: hours, settings and electricity
Run water-based floor heating steadily through the cold season with a thermostat, and lower it by 2 or 3 degrees at night or when you are away, instead of switching it fully on and off. The floor holds heat, so it works best as a slow, constant system.
By GSAT Group, floor heating in Lebanon since 1990. Updated 2026-10-27.
On all day, or on and off?
A screed floor takes a few hours to warm up and a few hours to cool down. Switching it off every morning and on every evening means the room is never quite comfortable. A room thermostat with a small night setback gives steady warmth at a lower cost.
Electric mats under a tile in a bathroom are different: they warm up quickly and can run on a timer for the hours you use the room.
Does it heat the whole room?
Yes. The whole floor becomes a gentle radiator, so warmth spreads evenly from the floor up, with no cold corners and no hot air collecting at the ceiling. In a well-insulated room it is enough on its own.
Does it use a lot of electricity?
A water-based system uses electricity only for its pumps and controls, plus the heat pump if that is the heat source. The heat itself comes from the boiler, heat pump or solar. Electric mats use electricity for all their heat, which is why they are best kept to small rooms.
What temperature?
Most homes are comfortable at 20 to 22°C room temperature. The floor surface stays only a few degrees warmer than the room: warm to bare feet, never hot.
Questions people also ask
How many hours a day should underfloor heating be on?
Water-based floor heating works best running steadily through the cold season on a thermostat, with a 2 to 3 degree setback at night, rather than a few hours a day.
Do you leave heated floors on all the time?
Hydronic floors, yes, on a thermostat with a night setback. Electric bathroom mats can run on a timer.
Do heated floors heat the entire room?
Yes. Heat spreads across the whole floor, so the room warms evenly with no cold corners.
Does underfloor heating use a lot of electricity?
A water-based system uses electricity only for pumps and controls, plus a heat pump if you have one. Electric mats use electricity for all their heat.
Does a heated floor use a lot of electricity?
Electric mats do over a large area. Hydronic floor heating takes its heat from a boiler, heat pump or solar, so it uses far less electricity.