Buildings in the EU contribute significantly to energy consumption and greenhouse gas emissions, with HVAC systems being major contributors. This paper assesses the impact of the resilience of various cooling strategies on thermal comfort, energy consumption, and GHG emissions in the residential building stock in Belgium. This study uses an innovative approach for sizing and designing cooling systems, considering the impact of climate change on future weather conditions and extreme heatwaves. The findings reveal alarming temperature increases, with potential rises of up to 4.1 °C from the 2010s to the 2090s, particularly in the high-emission SSP5-8.5 scenario. The study investigates three cooling strategies: scenario 1 (mechanical ventilation), scenario 2 (mechanical ventilation and natural ventilation), and scenario 3 (mechanical ventilation, natural ventilation, and split system). In scenario 1, there is a notable increase in Indoor Overheating Degree (IOhD), reaching up to 586% in the 2090s for semi-detached buildings, while scenario 2 consistently reduces IOhD, reaching only 0.2 °C by the 2090s. Scenario 3 achieves near-zero IOhD by the 2050s and 2090s. Notably, the “Heatwave [2081–2100]" exhibits unprecedented daytime temperatures, peaking at 46.0 °C. During the 2054 heatwave, insulated buildings maintained the Indoor Operative Temperature (IOpT) below 40 °C, whereas non-insulated buildings reached 44.3 °C, indicating challenges in meeting thermal comfort standards. Furthermore, cooling energy consumption increased by 106%–141% in the 2050s and surge by 174%–280% in the 2090s compared to the 2010s, along with significant GHG emissions growth in the future scenarios, particularly in SSP5-8.5.