Heat Recovery Ventilation Systems

Constant Fresh Air is essential to Human Health

We all need around 30 cubic meters of fresh air every hour to stay healthy & alert. You know the feeling of stuffy air and the tiredness that creeps on in the evening when carbon dioxide levels in our homes are creeping up. It only gets worse overnight when we shut our bedroom doors and keep the room closed up.

It’s always been good practice to sleep with windows open for a really good night sleep. But how many of us are happy to do this on a cold winter night or even in summer when you’ve cooled down the bedroom only to let in all that hot air and noise from outside. We don’t – so there has to be an answer in this day & age.

There is – it’s Heat Recovery Ventilation with Zehnder’s HRV from PASSIVHAUS PERTH

Filtering Supply Air Removes Dust & Pollen

Dust seems to creep up on us all the time. It’s under the furniture; on any and every horizontal surface in no time. Filtering the fresh air that comes into your home combats this build up and means that you will not be taking in the pollution from outside with every breath.

Filtering the incoming air removes critters, pollen & allergens and makes breathing easier for allergy sufferers as well as cutting cleaning & dusting time.

You can breathe easy with Zehnder’s Heat Recovery Ventilation from PASSIVHAUS PERTH

Removing Stale, Contaminated Air removes Pollutants

As we use up Oxygen, we breathe out carbon dioxide, in warm weather just in the same way as we can see huff on cold mornings. This builds up in in our homes and eventually reaches toxic levels. We’ve heard about VOC’s (Volatile Organic Compounds) and off-gassing from furnishings and plastics and glues in our homes and how toxic these can be when they build up in enclosed, unventilated spaces in our homes.

To make the home fresh again these gasses must be diluted and removed along with all the other odours and pollutants we create. The extract systems we usually install in our homes to take away odours and moisture simple create drafts of cold or hot air leaking in from outside with more moisture, dust & pollen and cause us to use more energy to bring the temperature back to comfort levels.

All this can be achieved in one automatic process with a balanced Heat Recovery Ventilation System from PASSIVHAUS PERTH

Removing Moisture prevents Condensation, Mould and Allergens

High relative humidity is caused by increased moisture in the air from cooking, showering, clothes washing and particularly drying, and can be clearly seen in the form of condensation on cold surfaces. The resulting dampness is a perfect breeding ground for the mould which produces spores that cause allergies.

Removing the moist air from bathrooms and laundries and from over stove tops with extract fans reduces the problem of condensation but at an enormous cost in lost energy. Utilising a balanced heat recovery ventilation system from Zehnder eliminates this moisture threat from your home without creating uncomfortable drafts.

Whole House Ventilation

Fresh air is supplied to all living areas so those cold rooms or overheated upstairs spaces are a thing of the past. The same temperature air is supplied to all rooms in your home so there are no more freezing or stifling unusable rooms.

Hot, stale contaminated air extracted from your bathrooms, toilets, laundry and kitchen passes through a heat recovery core inside your ventilation unit and the heat leaving your home tempers the incoming fresh air at up to 96% efficiency.

The same process works in summer with the cooling energy being captured and recycled into the incoming fresh air – reducing heating & cooling costs

Energy Efficiency

Everything in the Zehnder system is designed for energy efficiency. The flexible ducts have a smooth inside surface to reduce air resistance so the fans use less energy and make the system whisper quiet.

The cost of running the high efficiency EC fan motors is far outweighed by the savings in energy to re-heat or re-cool the replacement air when extraction systems are run and when the air outside is cooler than you’ve set in summer the unit automatically opens the Summer Bypass and gives you free cooling without heat recovery.

Passivhaus Perth are authorized agents and installers for Zehnder Heat Recovery Ventilation units and there is a model in their range to suit every size of home.

Contact us today for a free design and quote.

Ground Source Heat Exchanger

Preconditioning incoming fresh air using the constant temperature of the ground below the surface can increase the efficiency of a heat recovery system by warming the incoming fresh air in winter and cooling the incoming hot air on a summers day.

  • A brine filled ground loop is buried 3 to 3 and a half metres below the surface of the ground or through a sealed dip pipe loop in your garden bore.
  • The integrated water pump moves the brine through the ground loop at 8 l/min
  • The temperature of the brine is then modified by the temperature of the surrounding earth
  • The brine loop is connected to the ComfoFond-L Eco which draws in air through an external wall
  • The incoming air is filtered and passed through a liquid-to-air heat exchanger
  • The tempering energy of the brine loop is passed to this air which is then delivered into the ComfoAir heat recovery unit for further tempering before being supplied to the habitable rooms of the home

PASSIVHAUS PERTH have a range of Zehnder HRV and ERV units available to suit any size of building:

From studios and Tiny Houses to one-bedroom apartments where the Zehnder ComfoSpot 250 and the ComfoAir C70 will provide balanced constant filtered fresh air right up to the new Q Series units in 350, 450 and 600 versions.

Download brochure here

Zehnder Comfosystems HRV Ventilation Units

ComfoAir 180


  • Designed specifically for flats and apartments up to 105m2 (2010 Building Regulations)
  • Low energy consumption thanks to highly efficient EC motors
  • Automatic 100% filtered bypass
  • Compact dimensions making CA180 ideal for installation in a kitchen or bathroom cupboard
  • The unit can be left or right handed
  • Designed for use with the unique ComfoPipe Plus Twin Duct system
  • Offers particular benefits for refurbishment projects
  • Features an additional supply air connection at the bottom of the unit for added installation flexibility

Passive House certified performance data – with standard heat exchanger (HRV)

  • Air flow rates of 90 – 143m3/h
  • Heat recovery efficiency of 83%
  • Power consumption at 100Pa of 0.27 Wh/m3
  • Maximum power consumption with pre-heater of 1250W
  • Air tightness and insulation
    • Internal leakage at 1.00%
    • External leakage at 1.10%

ComfoAir 200


  • Designed specifically for flats and apartments up to 110m2 (2010 Building Regulations)
  • Low energy consumption thanks to EC motors
  • Automatic 100% filtered bypass
  • Can be mounted on either walls or ceilings
  • Integrates simply and flexibly into building services

Passive House certified performance data – with standard heat exchanger (HRV)

  • Air flow rates of 60 – 150m3/h
  • Heat recovery efficiency of 92%
  • Electric power consumption at 100Pa of 0.42 Wh/m3
  • Maximum power consumption with pre-heater of 951W
  • Airtightness and insulation
    • Internal leakage at 2.84%
    • External leakage at 0.80%

ComfoAir Q


  • Passive House Certified
  • World Class 96% Heat Recovery Efficiency
  • Comfort-led design with smart pre-heater and auto air balancing
  • Filtered Summer-By Pass
  • Easy accurate installation and commissioning with SMART Phone app



What is an Enthalpy Exchanger?

The Zehnder Enthalpy Exchanger is designed to maintain comfortable moisture levels within the home.

Too much moisture can lead to mould and overheating. Too little causes dry eyes, chapped lips and an environment in which bacteria and viruses can thrive.

The information within this literature will explain how the Enthalpy Exchanger can help to prevent these issues.


What does Enthalpy involve?

The Zehnder Enthalpy Exchanger recovers both thermal and humidity energy from the stale air extracted from wet rooms around the home.

This additional humidity energy, which would otherwise have been lost, is transferred into the incoming fresh air stream before being supplied to habitable rooms.

Choosing the Enthalpy Exchanger, rather than the standard heat exchanger, means that the unit becomes an Energy Recovery Ventilation (ERV) system, as opposed to solely a Heat Recovery Ventilation (HRV) system.


For further information, see these ebooks from the Zehnder America website: