Mechanical ventilation heat recovery (MVHR)

MVHR

An MVHR system has a ventilation unit with two fans: one draws outside air in and supplies it to bedrooms and living rooms; the other extracts air from kitchens and bathrooms to exhaust to outside. Inside the unit there is a heat exchanger which transfers the heat from the outgoing air to the incoming air without any recirculation of the air itself.

The fans run all the time, but can be switched to different speeds – usually low, normal and boost – and these rates are adjusted at commissioning to suit the individual house. The unit includes filters which remove dirt (and insects) from the air supply.

A system of ducts is needed to distribute the air from the ventilation unit to and from the rooms in the dwelling, and there are also ducts between the unit and outside to bring in fresh air and exhaust stale air.

Always use a fully designed ductwork system – for domestic ventilation this would usually be done by the system supplier, however they may charge for this. Use the ductwork and fittings specified and don’t allow shortcuts with flexible or...

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Ventilation unit location is very important to both the efficiency and also the long term usability of the system. Ducts connecting to outside contain air at the outside temperature, so are effectively outside walls – we use insulated ducts but...

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There are set criteria for working out how much air to supply in a Passivhaus; these are provided in the manual for the Ventilation Final Protocol Worksheet, which is supplied with PHPP. Supply air and extract air are worked out differently, but...

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Mechanical Ventilation and Heat Recovery (MVHR) is likely to become increasingly common in UK developments. As building regulations demand better air tightness and lower energy consumption then sufficient ventilation and recovering heat from exhausted air will become more and more important....

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The MVHR commissioning protocol is NOT the same for Passivhaus Certification as it is for UK Building Regulations compliance.

In general commissioning should follow the protocol set out in the “Domestic Ventilation Compliance Guide”. However there are additional commissioning...

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Knight’s Place is a certified social housing development of 18 one and two-bedroom apartments, designed by Gale & Snowden Architects for Exeter City Council. 

With MVHR an integral feature of all Passivhaus developments, Zehnder’s ComfoAir 200 whole house heat recovery system, was...

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Green Building Store
PAUL Novus 300

Summary:

Passivhaus-certified PAUL MVHR unit for medium to large buildings. For advice on which MVHR unit is best for your project, please contact our ...

Product certification:
Passivhaus Certified
Featured project:
Wimbish II
Airflow Developments Ltd
Semi-Rigid Ducting Airflex Pro

A quick and easy to fit system of semi-rigid ducting that can result in up to 70% time saving during the on-site installation process. Airflex Pro has a crushability factor of 13kN/m2 and features anti-static and anti-bacterial...

Product certification:
SAP Appendix Q
Featured project:
N/A
Airflow Developments Ltd
Adroit DV245

The UK’s first Passive House approved, internet controllable residential MVHR unit that can ventilate properties up to 400m2. The DV245 comes with an automatic, 100% summer bypass, an “A” energy rating, the option...

Product certification:
Passivhaus Certified
Featured project:
N/A
Airflow Developments Ltd
Adroit DV145

The UK’s first Passive House approved, internet controllable residential MVHR unit that can ventilate properties up to 250m2. The DV145 comes with an automatic, 100% summer bypass, an “A” energy rating, the option...

Product certification:
Passivhaus Certified and SAP Appendix Q
Featured project:
N/A
Airflow Developments Ltd
Adroit DV110

The UK’s first Passive House approved, internet controllable residential MVHR unit that can ventilate properties up to 170m2. The DV110 comes with an automatic, 100% summer bypass, an “A” energy rating, the option...

Product certification:
Passivhaus Certified and SAP Appendix Q
Featured project:
Saffron Acres Social Housing Development, Leicester
Airflow Developments Ltd
Adroit DV96

The UK’s first Passive House approved, internet controllable residential MVHR unit that can ventilate properties up to 130m2. The DV96 comes with an automatic, 100% summer bypass, an “A” energy rating, the option...

Product certification:
Passivhaus Certified and SAP Appendix Q
Featured project:
Saffron Acres Social Housing Development, Leicester