Analysis of the impacts of retrofit actions on the life cycle energy consumption of typical neighbourhood dwellings

The residential sector is one of the most significant energy consumers and therefore contributes significantly to climate change. A study of not only the use of energy during the operation but also the associated consumption and emissions in the life cycle is required. One way to reduce life cycle energy consumption is through retro-fitting existing buildings. This study analysed the energy consumption and its greenhouse gas emissions after applying five sustainable retrofit measures. For this purpose, two typical neighbourhood dwellings were chosen, located in the city of Vitoria, in the state of Espirito Santo, Brazil. The analysis was conducted for the pre-operational and operational stages. Using pre-established standards, the energy of the building materials that compose the dwellings was calculated as well as the consumed operational energy. The labelling of the building envelopes was also verified, according to the simulation method specified by the Technical Quality Requirements for Energy Efficiency Levels of Residential Buildings (RTQ-R). The software programme used to calculate performance was EnergyPlus. The results indicated that adopting all retrofit measures yielded improvements in the life cycle for only one building, namely, a 15% reduction in energy consumption and a payback time of 10.4 years. Although these results are lower than those reported in some international studies, the analysis showed significant improvements in the operational stage of both buildings, in both labelling and energy consumption.