What you need to do is get a room thermometer, and take pictures of it throughout the day and keep a record.
The following is a must from a landlord:
The property must be able to maintain a temperature of at least 18°C in sleeping rooms and 21°C in living rooms when the temperature outside is minus 1°C.
Obviously individually you may be feeling alot more cold, for this sadly there is no solution if the above is been covered apart from getting more layers on.