Energy Retrofit of a 19th-Century Heritage Building Through Passive–Active Strategies: A Field-Informed H-BIM Palestinian Case Study

Heritage buildings sit outside most national energy codes, yet Palestine alone hosts over 3000 historic structures whose 80–120 cm two-leaf stone construction is absent from any published, measurement-grounded retrofit dataset. A 19th-century three-storey heritage building (Qaser Morcos, Bethlehem; net floor area 406 m2, volume 2100 m3) was investigated through (i) in situ measurements (heat-flux meter to ISO 9869-1; infrared thermography; illuminance survey); (ii) a Heritage Building Information Model (H-BIM) built in DesignBuilder v7 with EnergyPlus 25.1 and the Jerusalem-centre typical meteorological year weather file, with end-uses other than heating, ventilation and air conditioning (HVAC) calibrated to three years of measured electricity records and the HVAC baseline comfort-normalised; (iii) a Heritage Impact Assessment per EN 16883:2017; and (iv) a 5000-run Monte Carlo uncertainty analysis on five envelope and system inputs. Two retrofit stages were evaluated: Stage 1 (passive and renewable measures—roof insulation, shading elements, LED lighting with motion sensors, solar water heating, and a 20 kWp photovoltaic system) and Stage 2 (deep envelope and system upgrade—Stage 1 plus triple-glazing, Variable Refrigerant Flow system, and a 17.5 kWp photovoltaic system). Predicted final (delivered) electricity intensity falls from 94.5 to 71.2 kWh/m2·y under Stage 1 (−24.7%) and to 63.3 kWh/m2·y under Stage 2 (−33.0%; 90% Monte Carlo uncertainty interval 59.0–70.4 kWh/m2·y), both well below the Palestinian Energy Building Code limit of 120 kWh/m2·y. On-site generation exceeds post-retrofit electrical demand under both stages, yielding a net-positive electrical balance. Direct carbon dioxide emissions fall by 6.84 t/y (−33%) at Stage 2. Discounted paybacks are 4.6 y (Stage 1) and 10.4 y (Stage 2), with internal rates of return of 24.7% and 11.7%. All proposed interventions received project-team consensus scores of ≥3/5 against EN 16883:2017 heritage-impact criteria. This study delivers a replicable simulation-based workflow for the energy assessment and heritage-compatible retrofit of thick-walled Palestinian stone buildings and one of the first field-informed heritage-retrofit datasets from the Levant.