The U-values given by Switzerland’s agency for the building energy efficiency label (GEAK) were compared with actual in-situ U-value measurements.
GEAK U-values compared to measured U-values
Werner Hässig of Hässig Sustech presented his study at an event of the Forum Energie Zürich on 07th of March 2017. His study compared real-time measured U-values, with U-values given by GEAK. The study concludes that many GEAK U-values were up to 60% higher compared to the measured U-values. This means that in many cases walls were indeed better insulated than the U-value given by GEAK lead to expect. During the study Mr. Hässig performed 100 measurements with greenTEG’s gSKIN® U-Value Kit. The Swiss Federal Office for Energy, Flumroc AG, Isofloc AG, Agitec AG, Hochschule für Technik Rapperswil and GEAK supported the study.
Werner Hässig’s presentation can be found here. (German)
Can U-values be derived from infrared images?
In another exciting presentation, Christoph Tanner of Baucheck-Tanner presented the advantages and disadvantages of thermographic analyses. One of the topics he covered was whether it would be possible to derive U-values from infrared images. He concluded that increased insulation of a building element leads to more uncertainty pertaining given U-values based on infrared images.
In cases when uncertainty is on an acceptable level, the given measurements on badly insulated building elements are not of much use due to U-values being less of a deciding factor when a thick external insulation is required.
Christoph Tanner’s presentation can be viewed here. (German)