<p>This study analyzes the energy consumption of a residential villa in Mahres, Tunisia, using thermal and energy simulations with eQuest and PVsyst software. The aim of this study is to optimize the building's energy efficiency and reduce its carbon footprint by integrating renewable energies. The dynamic thermal simulation carried out with eQuest estimated annual electricity consumption at 9804.5 kWh/year. To reduce this consumption, a solar water heater and a photovoltaic system have been sized and simulated. The solar thermal system reduces annual electricity consumption for hot water from 4960 kWh to just 563.5 kWh. In addition, a 4.93 kWc photovoltaic system, optimized for local climatic conditions with a 34° slope and a south-facing orientation, was sized and designed to meet the villa's electrical needs. The PVsyst simulation indicates an annual production of 9.74 MWh, more than covering the building's energy needs. The economic study demonstrated the profitability of the solar systems, with payback times of 4.1 years for the solar water heater and 7.8 years for the photovoltaic system. These results confirm the relevance of integrating renewable energies to achieve a near-zero energy building in Tunisia. They highlight the potential of integrating solar energy into residential buildings as an effective lever to support Tunisia's energy transition, decrease dependence on fossil fuels, and promote sustainable construction adapted to the Mediterranean climate.</p>