Do you have a thermostat installed on your heating system and if not, why not! The best system is a centralised smart thermostat with built in timer and zone control. This can be used to programme what temperatures you want set, when you want heating and hot water to come on and to keep different temperatures in different rooms. You can also place individual thermostats on radiator valves.
When setting your thermostat, 19°C is a comfortable living temperature but only heat the rooms you use and set heating to come on in the morning instead of running throughout the night. Also don't forget to turn off heating and hot water when going on holidays if there is no risk of freezing pipes (or you have frost protection on the system which turns it on to prevent it freezing).
Finally, if you like gadgets look to get the latest smart thermostat. These can be controlled remotely via smart phones, auto adjust for seasonality and learn from how you use them to ensure you get the temperatures you want.