Life-cycle cost comparison of portable air cleaners and ventilation systems for respiratory infection control in a daycare centre

Ensuring a healthy indoor air environment in daycare settings is important because children are more susceptible to airborne infections and spend time indoors in a crowded space. However, limited resources and existing ventilation system constraints challenge the implementation of effective infection-control strategies. This study analyses life-cycle costs (LCC) of three different methods to improve indoor air quality in a daycare with mechanical ventilation: (1) enhancing the mechanical ventilation system, (2) purchasing portable air cleaners (PACs), and (3) renting PACs. The clean air delivery target was normalised across all cases to compare additional investment, energy and maintenance costs. The results show that purchasing PACs at mid-range unit price (4 € per (m 3 /h) CADR) provides up to 70% lower LCC than enhancing mechanical ventilation, especially in contexts where enhancing mechanical ventilation airflow rate is not feasible. Short-term PAC rental solutions are cost-effective for high-risk periods, offering up to 80% lower costs for a one-year deployment, although rental costs rose sharply over longer durations, finally surpassing PAC purchase costs. Enhanced mechanical ventilation required higher capital and energy costs as well as space needs in technical spaces and systems. The sensitivity analyses showed that the cost ranking remained stable across a reasonable range of unit prices, energy tariffs, discount rates, and system lifetimes. This study addresses a notable research gap by providing a direct, normalised life-cycle cost comparison between portable air purification and mechanical ventilation in a daycare setting. The findings support hybrid infection control strategies combining PACs and mechanical ventilation solutions based on local needs, building type, and risk profile.