MVHR – step 5
Passivhaus buildings are dependent on their MVHR system to ensure good indoor air quality. The correct design, installation and functioning of the MVHR system mean it will save around five times more energy than it consumes. Inappropriate installation or the specification of low quality components will cause noise intrusion to occupied areas of the building, irritating occupants. The following checks should be made:
The system is complete and installed correctly, with sound attenuators between the MVHR unit and distribution ductwork and between rooms. For certification purposes maintain a photographic record during the installation, particularly at penetrations of the intake and exhaust ducts through the building envelope. Check that vapour tight insulation and top-hat seals have been used on the intake and exhaust ducts.
All installed ductwork and the MVHR unit must be clean inside and free from site dust. Filters should be clean and dry and in place to protect the unit at start
up. These checks should be made before stating the system for the first time, or dust may be distributed throughout the entire ductwork.
All components that require maintenance such as post heater, filters, duct cleaning access points, fire dampers if fitted, and balancing valves are accessible.
UK fire regulations
UK fire regulations have been adhered to, for example air movement between rooms is via door under cuts, and that there are not vents at the top of fire doors.
Certificates and commissioning
The system has been properly commissioned by the Building Services engineer and commissioning certificates have been completed for Passivhaus certification. O&M manuals or a comprehensive user guide should be available to occupants at handover.
Read about steps one, two, three, four and five in our next articles.
Excerpt from “Passivhaus primer: Contractor’s guide. So you’ve been asked to build a Passivhaus?” by BRE.