Maintaining indoor environmental quality in residential buildings is essential for occupants’ comfort, productivity, and health, with effective mechanical ventilation playing a key role in removing or diluting indoor pollutants. A two-week experimental campaign was conducted in an apartment in Lyon, France, known for its poor urban air quality, assessing temperature, relative humidity, CO₂, and PM_2.5 concentrations. A model verification study was performed to compare experimental measurements against numerical modeling in the living room and bedroom, leading to errors in the accuracy of the sensors. In addition, this study also investigates the impact of different ventilation strategies on indoor air quality. This research evaluates a baseline mechanical exhaust-only ventilation approach with constant air volume against two innovative smart ventilation approaches: mechanical exhaust-only ventilation with humidity control and mechanical exhaust-only ventilation with room-level CO₂ and humidity control. A key contribution of this research is the novel coupling of multizone simulation models (DOMUS and CONTAM) with a CFD tool to refine pressure coefficients on the building façade, which enhances the accuracy of indoor air quality predictions. The smart ventilation strategies showed improvements, including a 20% reduction in CO₂ concentration and a 5% reduction in the third-quartile PM_2.5 concentration, highlighting their effectiveness in enhancing ventilation and pollutant dilution. This research provides valuable insights into advanced ventilation strategies and modeling techniques in urban environments.

A Demand-controlled ventilation (DCV) has been recognized as a promising solution for decreasing energy consumption while ensuring good Indoor Air Quality (IAQ) in buildings. However, its application in the residential sector has increased first recently. Implementation of DCV systems brings the problem related to assessing their performance, not only in the view of energy savings but also in the ability to ensure IAQ. The objectives of this paper were to introduce a multicriteria performance-based approach for the evaluation of residential ventilation systems with CONTAM airflows simulations; illustrate its applicability to three DCV strategies in the context of renovated apartment buildings in Denmark and challenge the minimal background airflow requirements anchored in the Danish building code. Our performance-based approach allows assessing ventilation performance regarding IAQ (CO₂, humidity, PM_2.5, and formaldehyde-based indicators), energy consumption, and ventilation heat loss. Our results show that DCV strategies can improve IAQ while decreasing airflows. For example, application of DCV reduced the cumulative indicator of occupant exposure to formaldehyde, IHCHO by 6 to 28 %, compared to the constant-airflow system. For humidity controlled mechanical exhaust ventilation, the heat loss can be reduced up 51%.

The construction sector faces crucial challenges relating to energy efficiency and the health of building occupants. Smart ventilation offers an alternative to reduce energy consumption and improve indoor air quality by constantly adapting airflows based on the occupancy and contaminants concentrations. Nevertheless, an analysis of the published literature shows that it is difficult to compare these systems in the absence of a standardised assessment of their performance. In this context, the present work performed a sensitivity analysis to evaluate the performance of 11 ventilation systems based on indoor air quality and energy indicators. In order to obtain a range of performance outcomes rather than just limited results, the systems were simulated for two housing geometries and six different climates. The results showed that no ventilation system presented the best performance in all metrics, with trade-offs between IAQ and energy efficiency. However, the systems MEV-rh (humidity based) and MVHR-rb1 (balanced with room-based control) presented an average performance throughout all the indicators evaluated. In addition, the most influential inputs were the ventilation flowrates and pollutant emissions, but the formaldehyde exposure had small variation (maximum of 26% difference) and similar trends to the PM2.5 across the systems. The climate did not present a great impact on most IAQ indicators (around 15%), except for humidity, particularly in humid climates. For future studies, it is recommended to simplify the analysis and focus on four key indicators and prioritize sensitivity-driven inputs (ventilation rates, emissions).