Effects of heating patterns on internal surface temperatures and risk of condensation

Abstract

The paper presents the method employed in order to investigate the effects of various heating patterns and schedules on internal surface temperatures of internal partitions and external walls. It shows that the dew point temperatures in dwellings are usually lower in cold weather, thus, in the more moderate zones, where dwellings are usually heated only intermittently, and thermal insulation levels are generally lower, the problem of surface condensation on walls may be more frequent. A dynamic thermal analysis was performed for various levels of thermal insulation and inertia of external walls, for intermittent heating schedules as well as for continuous heating. The most suitable heating schedules were derived for typical levels of thermal insulation. The results of the dynamic analysis indicate that, for the same heating schedules and living habits, lightweight walls require a larger thermal resistance, by 0.5 to 0.75 m 2°C/W, in order to provide the same level of protection against surface condensation. The paper shows also that, for the same building, in the cool climatic zone, more heating hours are necessary on warmer days than on the regular cool days in order to cope with the problem of surface condensation.