Today many companies use or offer "energy contracting".
It is about provision of heat or media - often with clear saving potential (energy saving contracting). On the basis of calibrated to national standards air meters or air energy meters to be launched at the end of 2018, a contractor can invest in a central air-conditioning system and sell the treated air to its users. This can be used both in stand-alone air-conditioning systems and in combined ventilation/heating/cooling systems now also capable of air delivery billing. This technology enables agreeing clear prices per cubic meter of air and per kWh of delivered cooled / heated air.