It is generally accepted that the summer in Iraq is relatively hot season, where the temperature sometimes reaches 60 Cº. Accordingly, most of the Iraqi houses are characterized as having a large area of windows with a single glass, which could be resulted in a significant loss in cooling energy. Hence, the present research concern is to examine the effect of using double glass windows (as an alternative to single glass) on the saving in which energy normally used in houses and buildings at July and August for different hours 3, 6, 9, 12, 15, 18, 21 and 24 P.m. A practical and realistic study was conducted. Three values of aspect ratio are used 30, 15 and 10 for the presence of air between the panels and in the presence of the argon gas for aspect ratio, 10 were practically investigated. The experimental results confirmed that using of the double glass with the presence of air as a medium for heat transfer between the two panels could be reduced the amount of heat transferred compared to that of single glass between (45-78), (54-85)and(58-88)%, while for argon it was (60-91)%.