Indoor environmental assessment: Comparing ventilation scenarios in pre- and post-retrofitted dwellings through test cells

Abstract

In the next few years, outdoor temperature is expected to increase significantly as a result of climate change, a noticeable phenomenon, especially in the Mediterranean. In this future scenario, ventilation is a low-cost and useful strategy for tackling indoor overheating, mainly in energy-poor housing buildings. This research assesses the influence of different ventilation systems, air rates and schedules on the thermal comfort and indoor air quality of a residential retrofitted space when compared to an un-retrofitted environment, through test cell measurements. To do so, the methodology combines on-site monitoring with numerical models, simultaneously analysing both spaces under the same climate conditions. Results obtained show barely perceptible differences between the implementation of a mechanical ventilation system and a natural one, when it comes to thermal comfort in spaces with low thermal inertia, highlighting the clear advantage of energy and economic savings of the passive system. • The differences between IAQ in pre-/post-retrofitted ventilated spaces are minimal. • Inadequate ventilation periods negatively affect both IAQ and thermal comfort. • Short-term ventilation periods are useful for occasionally reducing high CO 2 . • Long-term ventilation periods are required to maintain IAQ with high occupancy. • Night ventilation is effective if applied under specific thermal conditions.