Retro-Commissioning (Retro-Cx) and Re-Commissioning (Re-Cx) are for existing buildings.
The major difference between the two is that retro-commissioning is for buildings that have not undergone commissioning before, while re-commissioning is for buildings that have been commissioned previously. Both retro- and re-commissioning seek to optimize the building’s performance and increase the energy efficiency of existing systems. Retro-commissioning and re-commissioning can produce significant cost savings in existing buildings, depending on the building type, its location and the scope of the process.