Heat feeling problems as mentioned above originate mainly from the direct contact of human legs with the floor. In case of wall and ceiling heating these problems are not specific, so a higher surface temperature is allowed that leads to a higher specific heat output value and makes consequently less heating surface installation possible.
The on-the-wall heating and cooling registers represent a good compromise between underfloor and ceiling heating/cooling since there is, on one side, no essential contradiction between the convection heat transfer direction of heating and cooling (heating upwards, cooling downwards), and, on the other side, the human body turns generally to the wall with a larger body surface improving the radiation heat exchange effect this way.
Under the best applicable surface mainly the outer wall is to be understood. The outer wall is the most suitable for changing the otherwise cold surface to warm. This is illustrated in the following table, in which the temperature of different “U” value walls is examined. It is suitable for both heating and cooling, and the danger of furnishing from among the vertical surfaces is the less here.
The wall heating can also be considered as a vertical floor heating, so it is unnecessary to look for a new concept. In addition to the possibility of a rather pleasant heat feeling, the knowledge obtained and applied at the examination and dimensioning of underfloor heating is valid even in this case.
Wall heating effect on outer wall surfaces
Efforts should be made to distribute the heating surface on the length of the outer wall as even as possible. In case of a surface larger than necessary, the height of the surface with registers can be reduced (generally, it is not worth to distribute the registers higher than 2 meters). In case of small floor, wall and ceiling surface the use of the internal wall surfaces is also possible.