Older strata buildings across Sydney are running ventilation systems that were designed for different occupancy patterns and airtightness standards. Modern retrofits and cladding upgrades have made many of these buildings significantly more airtight — which means the original ventilation rates are no longer adequate.
The Airtightness Problem
Ventilation rates in older buildings relied on natural air infiltration through gaps in the building envelope. As buildings are upgraded for energy efficiency, those gaps are sealed — but the mechanical ventilation capacity is rarely upgraded at the same time.
Common Issues
Poor indoor air quality, condensation on windows and walls, and musty odours are the most common symptoms. In worst-case scenarios, inadequate ventilation contributes to mould growth that can cause structural damage and health issues for residents.
Upgrade Options
Heat recovery ventilation (HRV) systems are the preferred solution for strata upgrades. They introduce fresh air while recovering 70–85% of the heat energy from exhaust air — significantly reducing the heating penalty of ventilation in cooler climates.