International Energy Agency. Energy conservation in buildings and community systems programme. Annex XII, Windows and Fenestration. Report from step 2. Thermal transmission throug windows, selected examples to illustrate the need for a more standardized a

The objective of this part of the research was to illustrate the deviation in the values of the thermal transmission properties of windows and to identify the causes as a means to promote the need for and ways towards more standarized approaches, based on internationally co-ordinated research. For this purpose four examples of windows were selected and a comparison was made between standard values, results from hot box tests, from empirical relations and detailed calculations on both glazing and frame.