Understanding the complexities of building physics and human behaviour in achieving a nearly zero energy building

About 40% of the world’s energy consumption and approximately a third of greenhouse gas emissions are associated with buildings. As the percentage of new buildings relative to existing buildings is increasing at a rate of only 1% per year, retrofitting is recognised as the most immediate, pressing and cost effective mechanism to reduce energy consumption and carbon emissions in the building and construction sector. Preliminary pre-retrofit results of eight case study buildings examining the energy consumption, thermal comfort and human behaviour in typical Irish residential houses built over the last two decades are presented with the impact of human behaviour on energy consumption highlighted. The paper discusses how architects and engineers are going to have to not only understand the complexities of a buildings physics but also the behaviour and attitudes towards energy consumption of the people living inside them in order to develop a holistic retrofit design.The authors wish to acknowledge the financial support from Science Foundation Ireland (SFI) for this research (Grant No. RSF1295). The authors would also like to thank the National University of Ireland Galway and particularly the Department of Civil Engineering in the College of Engineering and Informatics for the help with the projec