The ducted heating is set at 20 deg. I turn it on when the temp drops to 15 deg. When it reaches 20 I turn it off as the house is good for maybe 3-4 hours before it drops to the 15 deg threshold again. This is sufficient for an evening, and the house is cooler and it's easier to sleep once the temperature drops down. In the morning I turn it on for an hour or so as this heats the bathroom to about 22 deg which is ideal for showering etc. and I always have a nice warm fluffy towel. I turn it off after that, as the sunshine (when there is any) keeps the house warm through the daylight hours. This does me for winter, and the bills aren't too outrageous so far. Also, running the ducted heating on this schedule means that in rainy weather I can put any wet washing on a rack over a vent in the morning and it's dry and ready to put away by the time I come home. Heating is so damn subjective and personal - what suits one person might not suit another.