Abstract

Improving indoor air quality (IAQ) in buildings is important for occupant health and well-being, but it can lead to higher energy use and greenhouse gas (GHG) emissions. This study explores how different IAQ improvement strategies affect the energy performance and environmental impact of a college building. Simulations were performed using EnergyPlus to evaluate ventilation methods (mechanical, hybrid), air purification systems, and upper-room UVGI disinfection. Additionally, several retrofit measures including heat recovery using heat exchangers, PV panels, and external wall insulation were tested to reduce the energy burden of increased ventilation.

The results showed that the baseline scenario, which included 100% outdoor air, had the lowest energy use of 321418.7 kWh but failed to maintain acceptable IAQ. Applying mechanical ventilation based on CIBSE guidelines improved IAQ but nearly doubled heating demand and increased energy consumption to 566820.6 kWh and annual emissions to 114.3 ton CO2 eq./yr. Hybrid ventilation further increased energy use due to added heat loss from window openings.  

Among all retrofitting strategies, the most effective was the addition of a heat exchanger at the outdoor air intake. This reduced heating demand by 65%, total site energy use by 51.9%, and GHG emissions by 51% compared to the CIBSE ventilation case. External wall insulation provided slight savings, while PV panels helped reduce source energy and electricity-related emissions, although their impact was limited due to continued reliance on natural gas for heating. 
In conclusion, while IAQ improvements can significantly raise energy use, applying heat recovery systems offers a practical way to reduce these impacts especially in 100% outdoor air ventilation units. The study highlights the importance of combining ventilation improvements with targeted retrofits to achieve both healthy indoor environments and reduced environmental footprint. 
 

Keywords: Civil engineering, health and wellbeing, air quality

How to Cite:

Abbaspour, A., (2026) “Energy and environmental impact of indoor air quality improvement and retrofit strategies in an educational building.”, New Vistas . doi: https://doi.org/10.36828/newvistas.362