The advantage is based on direct heating of the air without radiation losses caused by heating elements. Unlike hot water boilers, our systems are operating energy saving because there is no boiler water steadily heated in case it cools down. The air quality in residential buildings has significantly increased  because nowadays compartment air contains more and more synthetic particles, particular harmful substances and dust. These materials normally smoulder on the hot heating elements and mix with the room air and become inhaled - this effect is being avoided by DOLL- Air-heaters.

 Furthermore, air heaters in residential buildings are also combined with a fresh air supply line nowadays. It is also possible to mix an individual amount of fresh external air. In the summer these devices are utilisable as a partial air-conditioning system as well, as the building becomes vented with convenient fresh air and without burner operation. 

For additional improvement of the air quality the recirculating- and additional air is conducted through an air filter. The adjustment of the heating power takes place over a serially equipped  three-step-switch for summer, spring, autumn and winter operation. If demanded, it is also available in combination with a modern, individual thermostat-control with day-, night- and weekend programming. The air-channeling tubes always have to be measured and dimensioned with the proper diameter though as well as the air-grids for recirculating- and fresh air-supply of each single room. For an individual solution we are gladly providing answers and consultation service on site.