What are the similarities and differences between an energy audit and an energy management system based on the ISO 50001 standard?

Answer by Helen Santalla (Creara)

What is an energy audit (EA)?

An energy audit is a systematic procedure to obtain adequate knowledge of the profile of the existing energy consumption of a particular site and to determine and quantify the energy savings potential in a cost-efficient manner and provide a report.

What is an energy management system based on the ISO 50001 standard (EMS)?

An energy management system is a set of interrelated or interacting elements belonging to a plan which sets an energy efficiency objective and a strategy to achieve elements.

The big difference between them is that while the EA is a timely study, EMS seeks continuous improvement by continuous monitoring that is necessary and sustained over time. The EA needs a timely effort to identify potential savings while EMS needs a sustained effort over time, not only for the identification of the potential savings but also for the maintenance of the system itself throughout the whole year.

In both cases it is essential to properly define the scope before you start working.

Both solutions provide the identification of existing energy saving potential, resulting in a decrease in energy consumption, greenhouse gas emissions and thus reducing the cost associated to that consumption.


The EA should be performed by a technician, if possible outside the normal operation of the site under study, and will involve the collaboration of the company’s staff. The EMS also needs the cooperation of the staff, not only for the timely collaboration for the implementation of the system but also to maintain it over time (continuous improvement cycle). In addition, the participation of a certification body to endorse good performance is needed.


The EA has a variable lead time but, for instance, a month's work is needed to audit a location.

The EMS needs a minimum of four months’ work to be qualified for the certification.