The small diameter of the capillary tubes enables the capillary tube mats to be installed close to the ceiling surface. This minimizes the thermal resistance from the heating / cooling water to the thermally activated surface. The heating and cooling ceiling reacts to temperature changes in just a few minutes and achieves high specific heating and cooling capacities. It is irrelevant that the capillary tubes are made of plastic because the wall thickness of the capillary tubes is only 0.5 mm or 0.8 mm and thus hardly contributes to the overall thermal resistance. The ceiling heating with capillary tube mats can be operated with low flow temperatures. The result is high energy efficiency. The large number of capillary tubes supports this effect and also ensures a very even surface temperature that is close to the mean water temperature. Test certificates for the standard cooling capacity according to EN14240 and the standard heating capacity according to EN14037 are available for standard installation situations.