Photovoltaic systems are designed according to specific energy needs; the bigger the needs, the bigger the system. So saving energy is an important key for reducing the size and subsequently the cost of photovoltaic systems.

Energy needs are based on the power demand and usage time of the connected appliances. Therefore, either reducing demand or usage time both result in energy saving. Energy efficiency aims to save energy without affecting users comfort. This involves choosing more efficient equipment and a smarter use. A good example of reducing demand is the replacement of halogen spotlights by LED spotlights which are much more efficient. Reducing usage time could happen for example through the replacement of conventional switches by occupancy sensors. Both of them either lamps or switches replacement resulting on energy saving.

The role of the technician here is to, first, identify and inform users of all the energy saving opportunities. Then, after the system has been sized and installed, the technician should educate users in order to instill and maintain the habits of an energy efficient use. The user should here understand that small changes in his way of using energy enabled him to have a smaller and cheaper system; an efficient usage is the only way of maintaining the system under normal load conditions.