The position of the input switch may be changed to reflect how cold the next day is predicted to be. The input switch is normally thermostatic, cutting off the charge when the room reaches a certain temperature overnight. The exact setting needed will depend on the size of the storage heater, the desired room temperature during the day, the number of hours that this needs to be maintained, and the room's rate of heat loss under a given set of circumstances. Some experimenting may be needed to find the relationship between forecast outside temperature and best input setting for a particular room. Most storage heater users follow simpler guidelines; for example, in the middle of winter, it is often appropriate to turn the input switch to its maximum setting. There is no need to touch the input switch on a daily basis if the same sort of weather prevails for weeks at a time. There is no need to touch the input switch during the day, as storage heaters only use electricity at night.