Building orientation and occupancy patterns and their effect on interventions to reduce overheating in dwellings during heat waves

Multi-zone dynamic thermal simulation linked to a nodal airflow model, was used to assess and rank the effectiveness of selected passive heat wave mitigating interventions for reducing overheating during a heat wave period. The simulations were carried out for Victorian terraced houses in South East England using two different occupancy profiles: a family and an elderly couple and two different building orientations: front north facing and south facing. The ranking of interventions for bedrooms, where occupied hours are similar, remain broadly the same for both orientations and occupancy profiles, the most effective being the addition of external wall insulation in all cases. However in living rooms, which are unoccupied during daytime hours for the family but occupied for the elderly couple, the ranking order changes significantly. For elderly occupancy external window shutters replace external wall insulation as the most effective intervention when the living rooms face north and are the most effective for both occupancy profiles when the building is rotated to face south. Adding internal wall insulation reduces overheating in living rooms for the family occupancy scenario, but is found to increase overheating for elderly occupancy compared to the base case. When considering interventions to reduce overheating in dwellings, it is therefore critical to take into account the residents and their corresponding occupancy profile as well as building orientation.