Nowadays, the big amount of energy is spent in buildings, mainly in such sub- systems as heating, ventilation and cooling. Reducing energy consumption in this field is a trend, because of economic and environmental issues.

We try to model the energy consumption for heating/cooling air in simple building, which is modeled by one volume. Energy dissipation depends on the dimensions of building, the materials from which the house is built and outside temperature. But energy consumption can be reduced by efficient control of heating or cooling.

We propose a CoCoViLa package for modeling and simulation of HVAC systems. The system consists of several components, such as: building description, heater/cooler, controller, thermostat, electric heater, occupants, ventilation etc. The simulation results can help to choose parameters for comfort temperature, properties of the heater/cooler and modify the control algorithms.