How a Manhattan Office Tower Reduced Over-Ventilation with Occupancy-Based HVAC Control

This NexusCon 2025 presentation dives into a real-world deployment of occupancy-based HVAC control inside a Manhattan office tower. Elizabeth Redmond, Head of Sales at R-Zero, and John Vilani, VP of Energy Services at Grumman/Butkus Associates (Hines account), walk through how they tackled a familiar problem: buildings ventilated as if they’re always full, even when spaces sit mostly empty.

The project focused on a single tenant within a large, mixed-HVAC high-rise, where centralized air handlers and zone-level complexity made demand-controlled ventilation non-trivial. Rather than theory, they show how sensor data, BMS integration, and new sequences of operation actually came together in practice.

Behind the paywall, you’ll see where this kind of project gets messy fast: getting occupancy data securely into the BMS, decoding zone-level constraints, and commissioning controls that won’t blow back on operators when spaces suddenly fill up. Elizabeth and John unpack what surprised them about data quality, recovery rates, and how far into the “weeds” teams must go for this to work reliably.

They also share how they’re now measuring impact—tracking standby mode performance, airflow reduction, and downstream energy and carbon KPIs across more than a million square feet. If you’re considering occupancy-based ventilation, new ASHRAE/IECC standby strategies, or continuous commissioning workflows, this recording shows what it really takes to move from concept to operations.

Watch the full recording inside Nexus Pro →