We have assumed that the heating is "ON" for 6 hours a day (3 hours in the morning and 3 hours at night).
Cost per month has been calculated @ 31 days per month.
Every 1⁰C reduction in the temperature setting of your thermostat will result in a 5% - 8% reduction in power usage and cost over 24 hours.
The calculation of running costs can only be approximate. The actual cost will depend on a number of considerations, user preferences, temperature and switch-on time setpoints, cost of energy etc.