Food can be set to slow-cook before leaving for the day so it is ready on return. Many homeowners with rooftop solar panels switch to slow cooking because it draws under 1 kW of power and can therefore be powered entirely by 1-2 kW panels during the day. Some models include timers or thermostats that bring food to a given temperature and then lower it. With a timerless cooker it is possible to use an external timer to stop cooking after a set time, or both to start and stop.