There are two possibilities to transfer heat

•     by warm ambient air
•     by heat radiation

Modern hot-water heating systems operate with low flow temperatures. This applies to condensing boiler technology as well as to solar heating systems. Thereby the radiators are heated up to temperatures between 50 and 60°C.

Underfloor heatings operate clearly below that. The warm air rises from the radiant floor surface to the ceiling, cools down at the walls and windows and falls down to the floor where this cool air is heated again by the radiant surface. With an underfloor heating the air rises to the ceiling and is cooled down at the walls. On the floor it is heated up again.

Both systems make circulate the air by convection.

Because of the little thermal proportion, radiation heating systems like the astra natural stone heating barely produce air circulation. The natural stone heating has higher temperatures, like a “tile stove”.

The radiation effect increases with the temperature. The effect of radiation heat is comparable to solar radiation because the objects in reach are heated directly.

The walls, ceiling, floor and furniture are heated up by irradiation.

There are only little temperature differences and little air circulation. Thus you feel comfortable at a temperature that is approximately 3°C lower than with convectional heating.

The structure of the building is heated evenly and this prevents possible humidity penetration of the walls of old buildings. Humid walls are thermal bridges.