It would help us all if our government and locally authorities were to demonstrate best practice. In the electrical industry, that would mean quite simply not seeing lights on in their offices at night when even the cleaner had finished for the day. Utilising a control system or BMS as it is sometimes referred, would rid the building of these issues. Simple use of presence detection and evaluating light levels which are affected by sunlight coming in through the windows could cut energy use for lighting dramatically.
Now, with that in mind, you could also use the same presence detector to let the air conditioning know that you have left your workspace and do not need the cooling on so much. In addition, add the control of the sun blinds too and these can drop when the sunlight is bright and hot so as to prevent overheating of a space and the subsequent effort (and £) to bring the temperature to an acceptable level.
All of this on one system which shares the same common power supply, cabling and 25 year history. You then have a system which is guaranteed to be able to meet you and your buildings needs and save money at the same time both Now and in the Future.