I'm experimenting with heating periods at the moment, I previously used to have it come on at 6am until 9am when the kids would be getting up and out to school, then have it come on again at around 12pm with regular on/off until 10pm. However, what I found was that the house would go from periods of too cold to too hot so what I'm trying at the moment is to have the radiator temperature at the lowest the unit allows but from 6am to 10pm the system is set to be on for 30 minutes off for 15. I'm hoping that this means that running lower temperature rads for around 10 hours a day costs the same or less running fairly hot rads for at least 8 hours a day and at least now I don't have the temperature highs and lows.