Mechanical ventilation with heat recovery (MVHR)

Central mechanical ventilation units extract stale, moist air from wet rooms and some also supply fresh, clean air to habitable rooms. To do this they need a ductwork system with the following components:

• Roof and/or wall terminals, which penetrate the building fabric
• Air-tight seals for the terminals in warm loft spaces to keep the building fabric air-tight
• Often insulated mass flow ductwork between the terminals and the ventilation unit to minimise the risk of condensation
• Sound attenuators downstream of the ventilation unit to minimise noise hindrance
• Ductwork systems between the ventilation unit and rooms to distribute air to and from them
• Supply and/or extract valves in the rooms