What could cause high running costs with an underfloor heating system?

If your customer is experiencing high running costs of their UFH system, you should check the following:

• That the UFH system is correctly electrically connected to the boiler to prevent short cycling and to ensure that the boiler is not running when it is not required.
• That the room temperatures and thermostat settings are not too high (typical comfort temperatures are 20˚C in living quarters and 18˚C in bedrooms).
• For any open windows or draughts. It is not unknown for windows to be opened in cold weather, as the internal comfort remains constant with thermostatic controls.
• That the boiler is running correctly. Has it been serviced and/or commissioned by an approved engineer. That the floor downward losses are high due to inadequate level of floor insulation.