The building sector has a significant contribution to global warming with direct or indirect emission of greenhouse gases, including CO2, CO, N2O, and CH4. Residential sector building contributes 36% of the total CO2 emission globally. The delocalized energy production and building with more sustainable design and low energy are the features that attract the project developers and architects to Renewable Energy Systems (RES). This chapter presents an attempt for the sustainability assessment of building-integrated renewable energy systems. The chapter identifies different RES used for onsite production of renewable energy for buildings’ energy need and their environmental and socio-economic impacts. Solar, wind, geothermal, and biomass energy are the primary sources for standalone and onsite energy production in building sector. The selection of RES technology highly depends on the availability of the energy source and type of required energy. The fluctuation in availability of renewable energy sources and the diverse nature of the required energy for building makes integrated renewable energy systems more sustainable for buildings energy requirement. LCA is a standard assessment method considered by researchers for the environmental analysis of building-integrated RES, while economic impact assessment is performed by Life Cycle Costing (LCC). All energy systems, including renewable and non-renewable energy systems, have an impact on the environment. Energy is strongly associated with environmental problems ranging from local to global issues. This includes air pollution, carbon emissions, ozone depletion, etc. For industrialized and developing countries, these problems can be more severe if not properly integrated with infrastructure. The technological non-complexity and local applicability make the solar energy preferred choice for buildings’ energy application. Solar energy is used both for the production of electrical and thermal energy. RES resulted in higher environmental sustainability with lower impact as compared to fossil fuels. However, the extent of impact strongly depends on variables like location and source of energy for the replaced energy system. Biomass-based system is the most economical system among the considered building-integrated RES. RES systems provide more job opportunity for the equivalent spent on fossil fuels based system. However, higher installation cost, lack of expertise, high maintenance, and high capital investment are the critical barriers in its application. A case study presenting a renewable energy system for building different energy needs such as heating, cooling, electricity, and hot and cold water production is presented at the end of the chapter.