The purpose of funding is the renewal of the heat supply and ventilation system in the OSZ nature and environment. The existing gas boilers are replaced by two wood pellet boilers and a gas peak load boiler. Wood as an energy source is intended to cover about 65 % of the heat demand. The existing ventilation system with cooling function is replaced by a system without cooling. Hydraulic balancing is carried out in connection with the renewal of the pumps (high-efficiency pumps) and an electronic single room control with central control is installed for optimisation.