A night setback system is used to control a heating system. A night setback system will lower the room temperature at night, which reduces heating costs. Office type buildings are not used at night, so lowering the room temperature will not cause discomfort.
A night setback system is often integrated into an office type building management system (BMS), or as part of an equivalent electronic control system, which has a built-in timer. The building must be warmed up again before the users arrive the next day. It therefore important that the BMS programming returns the setpoint to the normal day position early enough to heat the building before they arrive.
Small and simple control units can run night setback in residences, where the temperature is lowered to a lesser degree.
The heating system must always be left on if night setback is used. This prevents the building temperature falling too low and thus avoids potentially damaging condensation forming inside the building.
Night setback has next to no benefit in a room that has underfloor heating, because of the regulating inertia of the underfloor heating.