<p>Athens’ extensive urbanisation, lack of green areas and the extreme heat caused by increasingly frequent heat waves indicate the need for actions improving indoor and outdoor comfort, which is closely related to the energy consumption of the buildings. This work’s aim is to create a carbon neutral block in Athens on the 2050 horizon. The optimization of the block’s form based on principles of environmental design and climatic analysis was performed to enhance its environmental benefits. Simulations on the energy performance of the block and calculations on the ability to cover the energy loads by renewables were conducted. Finally, to meet the zero-carbon neutrality, a connection with the neighbouring blocks was established. The results demonstrate the benefits of a bioclimatic, carbon neutral building design in Athens and provide a practical prototype, which can be adapted in other projects, thereby enabling the shift to a more efficient and environmentally friendly built environment.</p>