Why We Should Never Underestimate Ventilation in Home Design

By Ian McCreeth, Managing Director, Anglo Nordic 

At a glance

• Ventilation failure creates condensation, mould growth and indoor air quality deterioration, yet is often compromised in pursuit of thermal efficiency 

• Energy efficiency and resident wellbeing are not competing priorities when ventilation is designed as essential infrastructure from the outset 

• Retrofit activity that improves airtightness without compensating ventilation provision shifts risk directly into resident health outcomes 

The unintended consequences of airtightness

Damp and mould enforcement has exposed a recurring pattern. Homes are made more airtight to improve thermal performance, but ventilation provision has not been adjusted to compensate. The result is condensation, mould growth, indoor air quality deterioration and resident health impact. 

This is not a failure of thermal efficiency, rather it is a failure of integration. Ventilation has been treated as secondary to heating, an operational variable rather than fundamental infrastructure. Where it is underspecified, poorly maintained or misunderstood by residents, homes cannot deliver the environmental stability required for health. 

In my view ventilation must be designed and maintained with the same discipline applied to heating and water. Where it is not, we risk energy efficiency measures creating unintended health consequences that undermine both resident wellbeing and landlord governance.