Paris Climate Agreement 2015, have been established to restrict the use of ozonedepleting substances and reduce greenhouse gas (GHG) emissions. [2] Buildings consume about 40% of global energy and are responsible for approximately onethird of the total world's GHG emissions. [3] Previous research shows that proven and commercially available technologies can reduce buildings' energy consumption by 30-80%. [4] One of the concepts that could be much helpful for this is renewablebased smart building energy systems with two-way interaction with the energy grids. [5] Among all renewable energy sources, abundant and affordable wind energy has been used by humankind for centuries, and small scale wind turbines (SSWTs), such as CFWTs, have grown and developed rapidly in the past few years. [6] The most notable features of CFWTs are high starting torque at low wind speed, self-starting capability, and simplicity of installation and structure, which together make them a suitable option for use in the urban environment. [7,8] Many researchers have already studied the techno-economic aspects of renewable-based smart building energy systems in Iran. Fazelpour et al. [9] investigated the feasibility of supplying a household electrical demand on Qeshm Island. After simulating and optimizing several combinations, it was concluded that the wind turbine (WT) and photovoltaic (PV) hybrid system with battery storage is the most cost-effective system, with a cost of energy (COE) of 0.604 $ kWh −1 and a total net present cost (NPC) of 30700 $ (based on 2015 US$). Baneshi and Hadianfard [10] analyzed a WT-PV-diesel-battery system for large nonresidential consumers with an average daily load demand of 9911 kWh in Shiraz. They presented the optimal hybrid system characteristics for off-grid and on-grid with the COE and renewable fraction values. Qolipour et al. [11] ranked six regions in Ardabil province in terms of generated electricity, depreciation values, and total income and net cost for the construction of household WTs with a generator and batteries by a Nonfractional DEA-BSC-Game theory hybrid approach. Mohammadi et al. [12] proposed a 100% renewable energy system for a residential single-family house in Hesarek, Tehran. Their final optimal solution with minimizing the cost function and the reliability constraint consists This work reports a technical, economic, and environmental investigation of the possibility of using a recently developed smallscale crossflow wind turbine (CFWT) to supply the energy demand of buildings for different integration scenarios. For this purpose, three CFWT-assisted building energy system configurations with heat pumps, with and without batteries, and two-way interaction with the local grid in two residential building models in Iran and Germany are investigated. Triobjective optimization with a Nondominated Sorting Genetic Algorithm (NSGA-II) is performed for finding the optimal configuration of the energy system in different configurations. For economic assessment, the Capital Budgeting Analysis meth...