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Tips to Help you Navigate Healthy Home Ventilation

Updated: Jul 5, 2023


Wellington Builders | Design & Architecture Services | Eco-Friendly Design | High Performing Home | Structural Insulated Panels | Energy-Efficient Home

Man taking a big breath on the beach

Every breath you take... Green Abode wants to ensure is a breath of fresh air!

One thing these past two years have taught us is the importance of fresh air. We've all been encouraged to open windows and doors (where possible) in our homes, workplaces, and classrooms to let the fresh air circulate and replace stale air that harbours bacteria and viruses.

While we know good ventilation is essential, there are still many New Zealand homes with damp, mould, and rot problems caused by poor ventilation. Thankfully, one of the things Wellington builders Green Abode focuses on when building a high-performing home is proper ventilation! While an airtight home contributes to energy efficiency, it also demands that attention be given to correct ventilation to ensure both comfort and performance.

Our lifestyles these days mean that more time is spent indoors, and although airtightness results in less infiltration of air, it also means there needs to be more intentionality about getting good airflow in and out of the house.


High-performing homes use MHVR (mechanical heat ventilation recovery) systems. MHRV systems should not be confused with the standard HRV systems supplied in many New Zealand homes.

MHVR systems work to replace 'stale' air from inside the house with fresh air from outside (not the attic), filtering out dust, pollen and other allergens before sending it to where it is needed. These systems are all about control, minimising the airflow in and out by the means you've chosen, and not having air seeping in and out through hundreds of small pockets throughout the house.

MHVR systems provide a healthy living environment by supplying your home with continuous clean airflow all year round. This healthy environment also promotes a longer-lasting home without all that mould, rot and decay!

Although there are decentralised ventilation options available, these are best used in apartment builds or spaces that have limited or no roof cavity.

Green Abode recommends using a centralised ventilation system in your high-performing home.

Centralised Ventilation

A centralised heating system is when heat is generated from one central point in the house. From this single source, a consistent temperature is maintained 24/7, 365 days a


The system itself can be mounted in a cupboard or ceiling void, and the air is distributed to or extracted from rooms through simple ceiling or wall grilles.

The heat that would normally be lost through traditional ventilation processes is recovered, filtered, and reused, thereby reducing heating bills in the colder months. Fresh, cold air entering the house in winter is also tempered to ensure a comfortable temperature, while in summer, the tempering can be bypassed, to ensure the indoors is kept cooler.

Green Abode homes use Zehnder MHVR systems such as the Zehnder ComfoAir 350 which is perfect for the average-sized home and is certified by the Passive House Institute.

Ventilation is something that needs to be considered in the planning stages of your build. Some things to discuss with your architect and builder are:

System Design - the system supplier will draw plans to show where the ducts are to go in each room of the house. The exact location of the ducts and grills can be discussed with the builder.

Thermal Envelope - the ventilation system should only create three penetrations through the thermal envelope (supply air, exhaust air and condensate drain).

Electrical - some systems need a wired controller to be in an easily accessible spot. They may also require a boost switch in bathrooms. The electrician will need to be kept in the loop with these decisions.

Talk to us if you are in the planning stages of your high-performing home! We would love to help you navigate these critical decisions for healthy home ventilation.

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