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Heat Recovery, Balanced Pressure Ventilation
Counter Cross Flow Heat Exchanger with Aluminium Core
German Designed & Manufactured.

Balanced Pressure Ventilation

This is important as the tighter building envelope in modern homes is not suitable for positive pressure.

Works by extracting air from damp areas (bathroom & kitchen), and pumping fresh outside air into all of the main living areas and bedrooms.

Meets the NZ Building Code.
It sounds obvious, but many systems don’t. The New Zealand Building Code requires homes to ventilate using outdoor air to maintain air purity. Ventilation systems that draw air from the roof space and not directly from outside do not comply with ventilation standard NZS4303:1990 “Ventilation for acceptable indoor air quality”. They cannot be used to comply with the Building Code Acceptable Solution for Ventilation.


There are two main types of plate heat exchange systems which are easily confused - 'Cross Flow' and 'Counter Cross Flow'.

A Cross Flow heat exchanger is easier and cheaper to manufacture however the inferior design lacks efficiency - it is difficult to obtain even 50% efficiency. We do not supply cross flow heat exchangers.

Counter Cross Flow provides a much larger area for heat transfer and as such a much higher efficiency - up to 90% in this case - meaning more heat is returned to the home.

Counter Cross Flow - Air Flow Diagram


Moisture Control

By removing moisture at source and introducing fresh outside air into bedrooms and living areas we create a cycle of air through the home, resulting in the removal of moisture and condensation.

Because a Passive Heat Exchanger is a static unit, you are only powering two fans to move the air within the home. This means the system is incredibly cheap to run.

It is important to remember that condensation is only a symptom of high moisture levels which are the real issue. In modern homes double glazing reduces visible condensation and can hide the true extent of a moisture problem until it affects health.



Don't be fooled by cheap systems that claim to do the same job.

There are a number of types of core, Paper Based/Permeable Membrane, Plastic, and Aluminium. Questions have been raised about the suitability of Paper Based/Permeable Membrane systems in the NZ market as these are considered susceptible to bacteria growth in our high humidity climate.

In particular, Paper Based/ Permeable Membrane systems should not be used to recover heat from moisture laden sources such as bathrooms... so, why bother?

Our Aluminium core heat exchanger is suitable for use in bathrooms and includes a condensation drain.


  • Positive Pressure:
    Ventilation systems that draw air from the roof space into the home and do not extract air from anywhere in the home.

  • Balanced Pressure:
    Ventilation Systems that have two separate but equal streams of air:
    1. Fresh air in
    2. Damp air out

  • Heat Recovery:
    Removing heat from outgoing air and transferring this to incoming air. Air streams do not mix.

  • Passive Heat Exchanger:
    No mechanical or electronic parts (air flow is driven by separate fans). Relies on heat from one air stream being conducted by a thin barrier and transferred to an opposing air stream.

  • Active Heat Recovery:
    A system patented by and exclusive to Tranzheat. Uses the same technology found in heat pumps to strip all usable heat from the outgoing air stream, resulting in a heat gain.

  • Heat Gain:
    When the fresh air entering the home is warmer than the air it is replacing.

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