Assessing the effectiveness of building envelope materials on existing buildings in the sub-tropical climate: A case study in Kathmandu Valley, Nepal

This paper is on the effect of building envelopes on thermal performance in the sub-tropical climate in Nepal. In today’s urbanized world, concrete buildings are growing and therefore, the greenery is decreasing significantly. Building and construction being one of the driving engines of the worldwide economy, it has become a main concern of sustainability. The Kathmandu Valley is the most densely populated urban area of Nepal, and energy availability has been a major problem in the Valley. Energy modeling exercise was performed through a simulation tool, Ecotect software, to calculate the energy performance of a residential building in the Kathmandu Valley. To attain these objectives, the necessary features of the building site were studied. The building was simulated by creating different building envelopes as scenario cases. Overall comparison was performed to elucidate the pros and cons and show the possibilities for modification of the building to adapt to climate change. The building with materials such as double brick cavity walls and double-glazed timber windows was found to be more effective in comparison to brick walls with cement plaster. The current study has shown that the building's annual energy demand could be reduced by up to 37.5% in the best-selected scenario.