Assessing noise and overheating in dwellings: Aligning acoustic and thermal models for partially open windows

Abstract

Building regulations increasingly require balanced solutions for thermal comfort and acoustic performance, particularly for naturally ventilated dwellings. England’s Approved Document O (ADO) establishes noise thresholds for bedrooms using open windows for ventilation, allowing partially open windows (POW) rather than fully open ones to balance sound insulation with overheating mitigation. This study addresses the fundamental challenge of aligning acoustic and thermal modelling methodologies for POWs. Through field measurements at eight residential sites with diverse window configurations, we compared two assessment approaches: the theoretically-derived ‘Acoustic Open Area’ (AcOA) and the ventilation-based ‘Equivalent Area’ (EA). Statistical analysis revealed comparable accuracy between methods (standard deviations of 1.9 and 1.8 dB respectively), with no significant additional uncertainty when using EA instead of AcOA. Spectral analysis demonstrated that while measured sound insulation varies considerably with frequency, both methods effectively predict overall performance for typical environmental noise sources. This research establishes that EA – already used in thermal modelling – can reliably replace AcOA for acoustic assessments, significantly simplifying interdisciplinary coordination. These findings provide practical guidance for designers, engineers, and regulators developing integrated façade solutions that simultaneously address ventilation requirements and acoustic comfort.