furnace combines the combustion with the heat exchange, using the latest indirect heating technology that the heat exchange is taken place at the position of the high temperature in the furnace. The smoke and the air go into the different channels, without any pollution for the heating. The heat efficiency rate is high (up to 60-75%).The temperature increase is fast. The furnace is small in size, easy in the installation, reliable in the operation and low in the price (making a comparison with one ton boiler, the price of this system is only half price of the heating system for the boiler).