Climate change impact on envelope retrofit effectiveness: energy and carbon performance of Italian residential and office buildings today vs. 2050

Abstract

Buildings significantly contribute to global energy consumption and CO₂ emissions, and their performance is increasingly challenged by rising cooling demands under climate change. While many studies assess envelope retrofit measures, most focus on a single building use. This study addresses this gap through a comparative analysis across building typologies, uses, and climatic conditions. The effects of climate change and envelope retrofit strategies on thermal energy demand (TED) and CO₂ emissions are evaluated for four representative Italian building typologies—apartment block, multifamily building, terraced house, and single-family house—considering residential and office uses, standard and high internal loads, and current and 2050 climate conditions. Dynamic simulations are performed using EnergyPlus for four Italian climatic zones. Several retrofit options are analyzed, including insulation measures, window replacement, cool roofs, and a global retrofit. The global retrofit provides the largest benefits, reducing TED and CO₂ emissions by up to 65% and 60% under current conditions, with a slight decrease in effectiveness (2–4%) toward 2050. Office buildings with high internal loads show smaller improvements than residential ones. Compact buildings exhibit greater climate resilience, whereas less compact typologies experience larger performance declines. Cool roofs are effective in mitigating cooling-related emissions under warmer climates, though their impact is limited in high-load office scenarios. Results highlight the need for adaptive and climate-resilient retrofit strategies in Mediterranean contexts.