According to the latest researches there are no doubts about the influence of indoor air temperature on the human body. In the current work was made simulations of heating the laboratory in the winter period by heat recovery ventilator (HRV) and combined system of HRV and floor radiators. According to our research it is better to use multi heating systems in terms of comfort people being. It is possible to heat the rooms only by HRV but it may result temperature differences on the high which may be uncomfortable for people. Simulation of the ventilation in the laboratory was made in ANSYS Fluent 14.0.