Abstract
A theoretical method was developed to analyze the effect of low-$\varepsilon$ coatings which have influence on thermal performance of vacuum windwo glazing and double pane glazing. The overall heat transfer coefficient(U) value and thermal performance were analyzed by theroretical method on various kins of windows. TRNSYS program was used to analyze total heating and cooling energy consumption on the model building which has various windows. As the result, better thermal insulation can be achieved on the vacuum window glazing than double pane glazing when low-$\varepsilon$ coating was done on the surface of glass. Total heating and cooling energy consumption was almost same on the double pane window glazing but was lessened on the vacuum window glazing when the window size of south direction increased. Therefore, low-$\varepsilon$ coating was very necessary for vacuum window glazing in order to improve thermal insulation performance and efficient energy conservation can be achieved by vacuum window glazing at the real building which has large window.
