One ceramic or metal heat generator is used for air heating installation, heats the air to a temperature of 90-95 ° C in the air chamber surrounding the generator. Then the heated air is distributed through the channels into the rooms, to be heated. Distribution of warm air to a distance of approx 8 m occurs by gravity (on its own), and for longer distances, the air should be forced through electric fans.

Air distribution channels should be clean and smooth, so that they do not resist. The temperature of the heated air in the ducts should not exceed 60 ° C, and at the outlet of the ducts, this temperature must not exceed 45 ° C.

Scheme of fire-air heating.

The opening for the inlet of warm air into the room is placed in the walls at a height of 1.0-1.5 m from the floor, supplying it with a metal door, which allow you to regulate the air supply. The opening for the used air return to the aggregate is placed in the wall above the floor or in the floor itself.

Central air heating can also be used for ventilation purposes, drawing in the air from the outside, by heating them and forcing them to heated rooms.

Adjusting the intake of air from the outside is quite complicated and burdensome. Overseas heaters are equipped with automatic regulating filters, humidifiers and electric fans.

Air heating with a supply of fresh air from the outside has superior hygienic advantages, but in installation and in operation it is almost 50% more expensive, and in the absence of humidification, the air does not have even half the required humidity. Abroad, air fire heating with automatic air circulation and mechanical activation of air circulation and often a combined circulation and flow heating system are used., that is, with partial use of fresh air. The heaters are manufactured at the factory, starting with sizes suitable for single-room rooms. Of course, all these heaters are metal and do not accumulate heat, some heat the air in the surrounding chamber by convection, others - directly through radiation. Such heaters are equipped with a filter and an air humidifier.

The cleanliness of the inflow and distribution channels in air heating is of great hygienic importance. Ducts should be made of clinker or machine bricks of the first grade, concrete with smooth surfaces or other materials, like zinc sheets, plastics, etc.. Hot and cold air ducts should be easily accessible and provided with tightly closed openings for cleaning.