Comparison of heat loss and air infiltration through the openings of Qajar and Pahlavi era houses in Tabriz

The rapidly growing world energy use has already raised concerns over energy resources and greenhouse gas (GHG) emissions. Since the global contribution from residential buildings towards energy consumption, has steadily increased between 20% and 40% and as large openings have considerable energy and heat loss in dwellings, this paper establishes a coefficient of heat loss and air infiltration through large openings in 10 historic dwellings (Qajar and Pahlavi era) in Tabriz, Iran. The results show that although Qajar era houses have larger windows than Pahlavi era equivalents, the rate of heat loss of openings per square meter of facades (Ĥ) and the air infiltration per square meter of facades (FA) of openings for Pahlavi era houses is more than the Qajar era equivalents. Therefore Openings of Qajar era houses have been designed more efficient than those of the Pahlavi era. Although the generally accepted way of building energy saving houses in cold climate has been to use small windows, the results indicates that instead of exploiting small openings in facades, it is possible to enlarge the windows to get better lighting conditions and simultaneously decrease the area of openings per square meter of facades for lower heat loss through these openings.