Special instructions for window U-Value measurement

Guidelines for set-up

For the main part, performing a U-value measurement of a window using a U-value KIT can be done according to the instruction described under section 3. However, a few points should be taken into account while performing glass measurements. Measurements of the U-Value according to ISO 9869-1 2014 standard section 7.1. can only be obtained if the measurement is conducted approximately one hour after sunset and stopped before sunrise to avoid the effects of solar radiation. Furthermore it requires a measurement interval over three subsequent nights and results not differing more than by 5%. If it is not practical to set up the measurement in the evening, the timer function can be used to postpone the start of the measurement for several hours (see section 3.7.). This allows one to set up the measurement in the afternoon. Alternatively, in the csv-file, data points obtained during daytime can be extracted as an excel file – a template can be provided by greenTEG upon request (email to [email protected]). This allows analysis of data gathered during the night and obtaining a graphical display of the result. Artificial light also has a large impact on the outcome of a window measurement. For reliable results it is therefore crucial that all lights in the room are switched off during the whole period of measurement.