C10 -- Comparative LCA of an Exhaust and Balanced Ventilation System: A Single-Family Case Study in Flanders

As global sustainability concerns continue to gain importance, there has been an increasing focus on reducing the environmental impact of buildings, primarily during the operational use phase. Consequently, this has led to the adoption of strategies such as enhanced insulation, energy-efficient heating systems, improved airtightness, etc. However, to simultaneously guarantee optimal indoor air quality and thermal comfort, the installation of a ventilation system becomes crucial. This paper presents a comparative assessment of the environmental impact of a balanced ventilation system with heat recovery and a demand-controlled exhaust ventilation system. The objectives of this research are to (1) assess the importance of individual components in the design of ventilation systems and (2) facilitate a comprehensive and fair comparison of the environmental impact of exhaust and balanced ventilation from a life cycle perspective. Therefore, a life cycle assessment (LCA) over a 60-year study period is conducted, adopting a cradle-to-grave approach. In a first step, a detailed data inventory is carried out, encompassing the air handling unit, emission system, distribution system, and other associated components. Subsequently, four ventilation scenarios are elaborated and applied to a Flemish terraced single-family dwelling: two demand-controlled exhaust ventilation systems, with secondary components in plastic or steel, and two balanced ventilation systems with heat recovery, again with plastic or steel components. Finally, the operational energy use is calculated via the Flemish EPB methodology. The results show that the balanced ventilation system with heat recovery exhibits a 36% lower environmental impact compared to the exhaust ventilation system. Despite the embodied impact that is 39-52% higher, this is outweighed by a 38% reduction in operational energy consumption. In addition, this research gives insight into how detailed ventilation systems should be considered in an LCA.