Because of the increasing cost of energy and the awareness of the impact of global warming, reducing fossil-energy consumption has become a key area for actions during the last decades. There is strong popular belief that the climate change is anthropogenic and attributed to fossil fuel consumption. Heating and cooling systems in residential and commercial buildings are the major energy consumer. In hot and country like Arabian Peninsula, the share of air conditioning systems excesses the half energy consumption. It is worth to mention that in such region 100 % of energy consumption coms from fossil fuel. This provides the challenge to study energy consumption of buildings and find methods to increase the performance of such systems.

Current paper shows the impact of different measures on reducing the cooling load of the buildings in hot climate. The examined measures are (1) U-value of the external shell, (2) indoor set-temperature, and (3) lighting efficacy. For this aim, a common type of residential house in Doha, was chosen as case study. The cooling load of the case study estimated using a simulation model bases on Hourly Analysis Program.

The calculations show that different measures have different impact on the annual cooling loading of the building. It was also shown that the effect of each measure depends on the construction thermal quality of the building. A brief economic comparison between the examined measured was done as well.