How can you lower energy consumption in building?

First the power Factor should be improved . then we can reduce the consumption using  presence sensors to turn off lights and AC if there are nobody in the room. shut down any other unnicessary loads.

Reduce the Unnessasary loads in building

good insulation and make better windows and use central heatin and cooling and use BMS

Reducing peak load, controlled lighting via optical relay, using a frequency converter on fans and air handling pumps that supply the building technical and drinking water