Corona touches, Corona unsettles, Corona makes you think. For example, about the ways viruses are transmitted. How does ceiling heating behave with regard to potential pathogens?
Many suppliers of surface heating systems advertise the healthy room air provided by a ceiling heating system. BEKA is one of them. But what constitutes healthy room air?
The coronavirus - similar to flu or cold viruses - is primarily transmitted via droplet infection, i.e. via tiny droplets that get into the air when sneezing, coughing or talking and are absorbed via the mucous membranes of the nose and throat. Some pathogens of diseases such as flu, chicken pox or measles even last quite a long time in the air of closed rooms. The more the air in the room is in motion, the more lively the pathogens can float around.
Less air movement thanks to ceiling heating
Surface heating minimises such air movements. Ceiling heating, in particular, works mainly by means of radiant heat. In contrast to radiator heating, the convective component and the associated air movement (warm air rises, cools on the cooler ceiling and sinks to the floor again, etc.) is very low. Less air movement means less stirring up of dust and tiny droplets containing viruses or bacteria. Dust and germs are therefore more likely to sink to the floor and stay there.
In addition to air circulation, another effect of radiant heating has a positive impact on the indoor climate: humidity. The optimum relative humidity for human well-being is 40-60%. In winter, the air can quickly become unpleasantly dry when the already dry cold outside air is heated to room temperature, as the relative humidity drops when it is heated. Dry air makes it easy for viruses in two ways. Dry room air dries out the mucous membranes, which are thus severely impaired in their protective function against pathogens. In addition, many viruses survive longer in dry air and are more infectious than in rooms with higher humidity.
Effect of ceiling heating on air humidity
So what does surface temperature control have to do with (relative) humidity? Surely it can't matter to the room air how it is heated? If you disregard the temperature differences within the room caused by convection heating, this may be true. Nevertheless, ceiling heating, for example, has a positive effect on relative humidity because the rooms do not have to be heated as much as with radiator heating. The heat radiation from the ceiling has a direct effect on all surfaces in the room (furniture, floor, walls and people). As a rule, people reach their comfortable temperature under a ceiling heating system already at temperatures that are about 2 degrees below those with radiator heating. In spring, this radiant heat effect is very easy to understand: there is a clear difference between standing in the shade at, say, 14 degrees and standing in the sun. Lower indoor air temperature means higher relative humidity. (Example: If there is a relative humidity of 40% in the room at 20°C and the air is further heated to 22°C, the relative humidity drops to 35.6%).
Of course, this does not mean that radiant heating protects against viruses or germs. Here, nothing beats the recommended protective measures such as washing hands, hygienic coughing and sneezing, and regular ventilation. But ceiling heating can make life much more pleasant for many susceptible or pre-stressed people such as allergy sufferers and minimise the risk of illness.
Application of ceiling heating and cooling in hospitals
Hôpital de Lagny in Marne-la-Vallée, France
Brandenburg Municipal Hospital, Brandenburg, Germany