Monte Sion Church
Improving indoor air quality through a right-sized ventilation and heat-recovery strategy for an all-electric church.
The challenge
Monte Sion Church is an all-electric church and community building in Manhattan’s East Village, with sanctuary and fellowship spaces shared by two congregations. The existing VRF system provided heating and cooling, but the tightly sealed building lacked dedicated outdoor-air ventilation and relied primarily on recirculated air. Occupancy varied considerably by schedule and event, while temperature stratification within the tall sanctuary created additional conditioning demands. The project therefore required a ventilation strategy that could respond to how the spaces were actually used while limiting additional heating and cooling demand.
The system approach
URBS installed environmental sensors in the sanctuary and fellowship hall to monitor indoor conditions over time. The measurements were combined with utility data to calibrate an energy model, establishing how the spaces performed under different occupancy conditions and allowing the ventilation system to be sized around actual demand. Based on the findings, URBS developed a concept using two compact energy-recovery ventilation units serving the primary spaces independently. The system recovers energy from outgoing air and coordinates with the existing VRF system, allowing ventilation to respond to occupancy and measured indoor-air conditions. The study established the design basis, equipment requirements and control strategy needed to move into design-build procurement.