Why ventilation is becoming non-negotiable in New Zealand homes
In Auckland, talking about the weather isn’t just a pastime — it’s practically a way of life. But in recent years, one theme has risen above the rest: humidity.
For much of the upper North Island, particularly Tāmaki Makaurau, humidity is more than a seasonal irritation. It’s a persistent, year-round issue that affects how people feel in their homes — and more importantly, how healthy those homes really are.
As a business committed to improving indoor environments across Aotearoa, we believe it’s time we moved beyond small talk about the humidity and addressed its root causes — through better ventilation, smarter system design, and healthier building practices.
Our housing stock isn’t coping
For decades, residential design in New Zealand relied heavily on natural ventilation — operable windows, passive airflow, and a “she’ll be right” approach.
But that model no longer works.
Recent findings from the BRANZ HEEP2 (Household Energy End-use Project) show a concerning picture:
- 48% of households reported visible mould, and 11% said mould covered areas larger than an A4 sheet.
- One in three homes is considered damp at least some of the time.
- 44% of respondents expressed a desire for their homes to be warmer.
Despite this, most people still believe their homes are healthy. But the evidence tells a different story.
While Auckland’s humidity is a frequent talking point, the need for effective ventilation extends far beyond the upper North Island.
Across Aotearoa, indoor environments are shaped by a diverse climate — from the colder, drier winters in Ōtautahi Christchurch and Ōtepoti Dunedin, to the persistent damp and high rainfall in Te Tai Tokerau Northland and the West Coast.
In many parts of the country, especially where homes are poorly insulated or lack mechanical systems, winter brings not only cold temperatures but also condensation, dampness, and mould.
The HEEP2 research reinforces this: even in regions where heating is common, many bedrooms — particularly children’s — remain unheated and under-ventilated.
Whether it’s to manage moisture, improve thermal comfort, or support respiratory health, ventilation isn’t just a solution for humid Auckland summers — it’s a year-round, nationwide priority.
What the experts are saying
At the recent NZGBC Housing Summit 2025, ventilation was a central topic — and for good reason. Our Head of Sustainability, Ryan P. and Senior Manager Business Development, Nish Mambatta, attended the event and engaged in important conversations about the future of healthy, resilient homes in Aotearoa.
A key takeaway from the summit: ventilation isn’t just a comfort feature — it’s essential for health and building durability. Especially as our climate gets warmer and wetter, and homes become better sealed, mechanical ventilation needs to be treated as a baseline, not a luxury.
We were also encouraged to see how NZGBC’s Homestar programme continues to raise the bar for healthier new homes — with strong requirements around thermal performance, moisture management, and ventilation.
But Homestar-rated homes still represent a small portion of new builds. Many homes — old and new — remain vulnerable to dampness, mould, and indoor air quality issues.
Humidity affects more than comfort
It’s not just about sticky skin and uncomfortable sleep.
High indoor humidity leads to:
- Mould growth
- Dust mite proliferation
- Respiratory conditions, including asthma and allergies
- Long-term damage to building materials and finishes
And in homes with limited airflow or poorly positioned heating and cooling systems, the problem is only amplified.
While heat pumps are an excellent solution for year-round temperature control, they don’t address moisture. In fact, they can sometimes mask underlying dampness — creating a cool, but still unhealthy, indoor environment.
That’s where mechanical ventilation matters
Mechanical ventilation systems play a vital role in:
- Removing stale, moist air
- Introducing fresh, filtered air
- Controlling condensation and preventing mould
- Improving comfort, health and energy efficiency
Whether it’s a positive pressure system, balanced heat recovery (MVHR), or a hybrid solution, mechanical systems deliver consistent performance — regardless of the weather or season.
Introducing our latest residential ventilation system
In response to growing demand for healthier, drier homes — especially in high-humidity areas like Auckland — we’re proud to launch our new residential mechanical ventilation unit, purpose-designed for New Zealand homes.
✅ Compact and easy to install
✅ Low-noise operation with smart controls (CO2 concentration & humidity)
✅ Helps manage humidity while improving air quality
✅ Designed to work seamlessly alongside heat pumps or as a standalone solution
This unit is part of our ongoing commitment to perfecting the air — not just in terms of temperature, but in overall air quality, comfort, and wellbeing.
Whether it’s for a Homestar-rated new build or a much-needed retrofit, it’s designed to meet the real challenges Kiwi homes face — and to help deliver healthier environments, year-round.
Building better for the climate we have
New Zealand’s climate is changing — and so are our expectations of what a healthy home should deliver. Auckland, in particular, requires design solutions that reflect local conditions: high humidity, warmer winters, and more frequent extreme rainfall.
That means:
- Passive design is no longer enough
- Window ventilation isn’t reliable in high-density or multi-storey housing
- Mechanical systems must become standard practice
By combining efficient heat pumps, smart controls, and effective ventilation, we can create homes that are healthier, drier, more comfortable, and aligned with New Zealand’s low-carbon future.
In closing
We have the tools — and the evidence — to do something about New Zealand's housing.
Let’s build and retrofit homes that aren’t just warm or cool, but truly healthy. Let’s design for the real climate outside our walls. And let’s make ventilation part of every conversation — not just at industry summits, but at every kitchen table too.
Because healthy homes start with healthy air.
Want to learn more about our new residential ventilation unit? Our team is here to help — whether you’re a builder, designer, or homeowner looking to improve indoor air quality.