Influence of air space thickness on thermal transmittance of wooden window

The paper discusses the influence of the width of air space between glasspanes on thermal transmittance of the window. The measurement was performed using a worm box method on the spruce frame with standard insulating glass units with pane thickness of 3 and 4 mm. Atmospheric (moist) air was sealed between the glass panes, and the proportion of the wood in the window area was 30 %. The paper confirms the positive influence of air space thickness on thermal insulation of windows. The results obtained here could be used for design and construction of windows.