Examination of the heat and air permeability of windows Untersuchung uber die Luft-und warme-durchlassigkeit von Fenstern

A study made to confirm the values given in german standard DIN 4701. considers theoretical natures of air permeability and the k-value as they concern windows. Finds that infiltration through windows without weather-stripping depends to such an extent on the quality of manufacture and fitting that essential differences between single-glazed, double-glazed and double windows scarcely exist. Finds no real difference between woodenand metal frames when new, but after normal wear and tear an average value of 3m(3)/h for each metre of gap at 1mm pressure difference is acceptable. For weatherstripped windows a figure of 1 m3/h is suggested. Types of windows tested are illustratedand the measured results given graphically