Climate change is considered as one of the biggest challenges in 21st century. Climate change is caused by the excessive use of heat exhausts such as air conditionings. The increasing use of mechanical cooling consumes more energy, discharges anthropogenic heat and CO2 emissions. This heat causes a rise in outdoor air temperature and worsens the urban thermal environment. Urban thermal comfort is important in promoting peoples' use of outdoor spaces. The objective of this research is to study the effect of anthropogenic heat on pedestrian thermal comfort within the urban space. Using infrared camera for different places in El Hussein square to identify the thermal performance under the climatic condition and under the mechanical heat generation sources. Different scenarios in El Hussein Square (Historical Cairo, Egypt) were carried out by simulations and modeling using ENVI-met and ANSYS/CFD to quantitatively assess the microclimatic thermal impacts of those heat exhausts. The results show the effect of heat exhaust in increasing the outdoor air temperature (heat island) as well as affect the outdoor thermal comfort of El Hussein Square due to the reduction of air flow between buildings. (C) 2015 Elsevier Ltd. All rights reserved.