Products resulting from the combustion of gas that contain harmful substances (carbon monoxide CO, carbon dioxide, CO₂, water vapor, H₂O) can penetrate into a room during the activity of Type A gas appliances. The concentration of oxygen, O₂, also decreases during the combustion of gas. Water steam should also be considered harmful. The results of calculations show that the rate of humidity is most important for determining the minimum volume of the room or the minimum volumetric flow rate of ventilation air.

Solar collector is designed to obtain part of heating requirements of the buildings from the sun. Air-type collector that use air as the heat transfer medium is one of the simplest methods of solar heating. This solar heating technique can be made part of house design and construction.

Aircondition systems record a heat loss and energy consumption by building operation. It is significant submission in building energy balance. This consumption can cause nonconforming energy building category according to law.