Energy supply is becoming an important issue and electricity system reliability is sometimes difficult to ensure. Energy efficiency in buildings in use is a key element in the search for solutions to current energy problems. Many buildings in use can improve their energy consumption performance by implementing simple energy efficiency measures (EEM) in their facilities. After carrying out such actions, savings may be continued with just minimal maintenance. An additional key phase in classical energy studies is to define EEM to be implemented by the intervention of an external energy expert, since resident staff may not have the time, sufficient knowledge, nor experience in EEM. The energy expert intervention is of short duration (several days), and the total cost of the action may be moderate. In this paper, authors present several real examples implemented in three buildings on the Universitat Politècnica de València (UPV) campus after an external energy expert review. Savings, certified using real measured consumption before and after the action, represent around 10% of the total annual energy consumption in the buildings, and the payback of the EEM is approximately a few months.