Ventilation

The supply of fresh air to occupied rooms and extraction of stale, moist, or polluted air. Building regulations Part F specifies minimum ventilation rates for new extensions. Wet rooms (kitchens, bathrooms) require local extract ventilation (typically 30–60 l/s). Habitable rooms require background ventilation (trickle vents in windows). Whole-house MVHR can provide both supply and extract ventilation in highly airtight buildings.