A background ventilator is a small ventilation opening designed to provide controllable whole dwelling ventilation. It allows for a constant flow of fresh air into a building while minimising drafts and noise. Background ventilators are typically installed in external walls and are crucial for maintaining indoor air quality in residential settings.
Background ventilators function by permitting a small amount of outdoor air to enter a building continuously, which helps to dilute indoor pollutants and moisture. They are particularly important in modern, energy-efficient homes that are designed to be airtight. Without adequate ventilation, these homes can suffer from stale air, condensation, and mould growth.
In a UK house retrofit scenario, a homeowner may replace old windows with new, double-glazed units that are more energy-efficient. However, this can inadvertently reduce the natural airflow in the home. To counteract this, background ventilators can be installed to ensure that fresh air enters the dwelling without compromising the thermal envelope. For instance, a typical installation might include background ventilators with an equivalent area of 8000 mm² in each habitable room, as recommended by Approved Document F of the Building Regulations.