Radiators should be installed preferably underneath the windows as showed on the picture, so that the heat they produce will combat the cold air flow that might enter from the window area.
Always put insulation around doors and windows in order to try to reduce loss of heat. At night, curtains and blinds should be closed for the same purpose.
Radiators should not be placed behind the doors, as when left open they might act as a barrier to the heat distribution.

A temperature of 20-22º C should be ideal for most people feeling comfortable indoors.

The difference of one degree in temperature can greatly influence the consumption of energy, causing unnecessary waste. For every degree over 20ºC the energy consumption will increase about 10%.
Temperatures come down quite a lot at night, therefore the energy consumption will also be higher at this time, and we recommend you to contract a Bi-Hourly rate from your electricity supplier.