Office buildings, hospitals, schools and stores are among the largest consumers of electricity. A significant part of this energy consumption is attributed to HVAC systems aimed for maintaining comfort for occupants. But in most cases these systems operate permanently and do not consider the actual occupancy rate. In fact, in most cases, HVAC systems are programmed to ensure comfort in case of maximum capacity. 


However, there is growing awareness regarding energy consumption, either from environmental and economic point of view. Not surprisingly, Spain is the country with highest gas and electricity costs in relation to our neighboring countries. But what level of savings are we talking about?


The potential savings depend on the weather, time of year and especially on how occupancy varies along the day, but most reports indicate minimum savings of 15%. We could take a look on an experiment in Norwegian schools (learn more about the experiments by clicking here).


The experiment took place in 81 randomly selected Norwegian schools, with 22 students on average. They compared two types of demand-controlled ventilation systems: one based on monitoring and control of carbon dioxide (CO2) concentration and another based on automatic people counters. The system based on CO2 monitoring and the system based on people counters reduce the energy use for ventilation purposes in the average classroom to, respectively, 38% and 51% of the corresponding energy use for a regular system.


Apart from monitoring occupancy in real time, companies concerned about energy efficiency will have to face another technological challenge: ensure that their HVAC systems are capable of responding to this new information.


Becoming an eco-efficient company requires a change of mindset which is not always easy, but the numbers speak for themselves and the effort, surely, will have its fair reward.