Indoor comfort all year around

Vireo HR155WM

This product has been superseded by the enhanced Zehnder ComfoAir CA155WM MVHR unit. For more information, click here. You can also access comprehensive information on the Zehnder range of industry leading MVHR units here.

Vireo. A heat recovery range designed to enable better, easier specification of ventilation in new housing.

Product Specification

Suitable for apartments and small houses up to 110m² this model has been designed to fit into kitchen cupboard for easy installation and access. Includes the latest in Greenwood SMART™ Technology including commissioning wizard. EST Best Practice Performance to 93% efficiency.

Greenwood SMART Technology is designed into this product:

Greenwood Smart Technology is designed into this product:



Models & Control Options



  • A Greenwood GIP Product (Guaranteed Installed Performance)
  • EST Best Practise Performance - 93% heat efficiency and 0.75w/l/s
  • Suitable for apartments and small houses up to 110m²
  • SAP Testing: Suitable for Kitchen + 3 additional wet rooms (ADF 2010)
  • SAP Testing: Suitable for Kitchen + 4 additional wet rooms (ADF 2006)
  • Excellent pressure handling allowing lower running speeds and low noise
  • Manufactured and Independently tested in the UK

  • True Summer By-Pass : Unlike others, it provides 365 days of Fresh Filtered Air

Greenwood SummerSMART technology has been designed to reduce issues with overheating in the summer in a true and effective way - unlike many other units available in the market.

When the by-pass is activated, the Heat Recovery System remains TRUE. In other words it continues to provide a balanced ventilation to the entire house by by-passing the heat exchanger and NOT slowing down or shutting off the supply air.

In addition, it still filters the supply air during the by-pass mode. Many other units on the market operate a summer/filter by-pass mode which further affects Indoor Air Quality, especially in homes where allergies and asthma are present.
Greenwood SummerSMART is completely innovative and unique and has been designed to maximise comfort at at all times as well as ensure Indoor Air Quality is maintained.

  • 70%* quicker install time can easily be achieved with innovative condensate technology

As a result of working directly with installers, we have developed revolutionary technology - DISO (Dual Inlet Single Outlet).

DISO allows condensate to be collected on either side of the unit without issue which enables Vireo to be the only true universal product on the market.. The unit can simply be handed (Right or Left) at the touch of a button after installation through the set-up wizard. This removes the need to hand the unit on site which usually involves a lengthy disassemble of the product, adding more risk to the overall installation - this can take up to 20 mins!

  • Semi- Rigid Ducting: Bend it - Shape it - Anyway you want it - Ideal for MVHR Installations
    ComfoTube Semi Rigid Ducting is a revolutionary development in ducting for residential ventilation installations. Perfect for whole house heat recovery, ComfoTube is supplied on long rolls and can minimise connections by up to 75%! Designed with a strong and crush resistant construction, ComfoTube is a radial ducting system which dramatically reduces any issues with noise and air leakage as each room is provided with an individual run, ensuring specified ventilation rates can be met easily. No sealants or tapes are required with ComfoTube installations - Winner of Housebuilder Products Brand new Product of the Year 2013.

    Watch ComfoTube in action: 3 Bed House + MVHR

Greenwood GIP Product
Guaranteed Installed Performance (GIP) is a fundamental part of Building Regulation compliance and focuses on signing off the installation for the first time.

A Greenwood GIP Product provides;

- 100% airflow adjustability
- Low energy motor technology for the most efficient performance
- SMART Technology to make installation and commissioning easy as well as continued GIP in the home for the occupant
- Independent CE Testing

Wiring: Must comply with IEE Regulations

Fuse: 3 amp (when unit is supplied from a 6A lighting circuit, no local fuse is required)

Electrical specification:230V~50Hz Class II

• Supplied with fixing bracket to allow screw fixing for increased support
• Install using rigid aluminium, PVC, galvanised or semi-rigid plastic ducting
• Install in wall or cupboard space
• Installation and user manuals supplied with each unit

These are the typical ancillaries required for the installation of the Vireo HR155CM in an apartment or a house - to view ancillaries in more detail, please click here

Zehnder ComfoTube
Flat 51
Steel duct
GS2 switch
GRC1 controller
Heat exchanger

Ideal for apartments and small houses, Vireo HR155WM is a compact heat recovery system which can easily be sited in a 600mm wide kitchen cupboard. With the increasing space restrictions and on-going focus to remove serviceable products from the loft space, Vireo is one of only a handful of small heat recovery systems which still deliver excellent airflow performance in line with Building Regulation requirements.

The 2010 Building Regulations increased airflow rates and removed infiltration from the whole house ventilation rate calculation - meaning increases of up to 20%. Simply increasing the running speeds of existing products to account for these new airflow rates will increase operational noise. Vireo offers this new optimal performance without energy penalty and nuisance running noise within the living environment.

In just 8 simple steps, Vireo can be set up and commissioned - all via an 'iPod style' controller located at the front of the unit. This simple and easy process contributes to GIP being achieved whilst keeping installers happy with fuss-free onsite requirements. Watch our YouTube Video to see the wizard in action

Vireo's boost ventilation rates can be controlled by humidity levels in the property. Greenwood HumidiSMART is patented technology that uses man-made spikes to boost ventilation, rather than waiting for a generic point to be reached.

Our Carbon SMART products are Low Energy Solutions suitable for new and existing homes