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Kiwi properties like Petri dishes for Covid

Kiwi properties like Petri dishes for Covid and other viruses?

A New Zealand building performance technology company with over 500 environmental monitoring systems in properties nationwide is warning that Kiwi properties are overwhelmingly under-ventilated, making most homes and buildings super transmission sites for Covid-19.

Tether is a New Zealand-based tech company founded in 2018 to solve building performance problems and thereby improve people's health, reduce cost and create a sustainable future through a range of software and hardware products designed, developed, and manufactured from the ground up in New Zealand. The company's proof-of-performance solutions enable data-driven insights through modelling, monitoring and data analysis.

Founder and CEO of New Zealand founded tech company Tether says that our building codes and standards for ventilation are 30 years out of date, with the consequence that CO2 levels in most properties – even homes – are through the roof.

"Ventilation – essentially the movement of air through a property – is measured by proxies such as the level of CO2 in a property. More than 1000 parts per million (ppm) is undesirable, but the norm in New Zealand."

With every additional 400 ppm of CO2 added to a room over fresh air, which averages around 410 ppm, the risk of transmissibility compounds. If the CO2 content in your building jumps from 410 ppm to 1610 ppm then the transmission risk of COVID would triple, for example.

"The data tells us that the average New Zealand bedroom is likely to exceed the 1000 ppm of CO2 at night. Café's, gyms and office buildings exceed 1000 ppm daily, but context is everything. For example, while a café may exceed 1000 ppm of CO2 daily, the nature of the business makes this less than a threat than, say, a gym.

"It's not just Covid-19. New Zealand homes struggle with dampness and mould. We have the highest rates of respiratory diseases in the world because our ventilation is abysmal. It all goes back to an outdated building code."

Van Blerk said that while there are currently active discussions about updating New Zealand's G4 and H1 building code – which is concerned with building performance around energy and physical conditions – the transmissibility of future variants of Covid-19 and other viruses needs consideration.

"Ventilation is essential. We know this today, but they didn't realise that 30 years ago, and that's when the building codes were written.

"Once lockdown finishes, we all go back to our lives – offices, gyms, cafes, dormitories and other places where ventilation is poor, and this makes it too easy for airborne viruses."

Van Blerk acknowledges that healthy buildings are some way in the future but says there are some things we can do in the interim.

1. Educate yourself

"Educate yourself on ventilation – the dos and the don'ts. Understand, for example, that air moves from high pressure to low pressure. So when you open a door, the pressure drops and the air – which may or may not be contaminated – makes a beeline for that open door.

"There is no substitute for an educated public. If you understand ventilation, you can expect and demand higher standards for the health of you, your family and the people in your organisation."

2. Monitor your environment

Knowledge is power. Measure things like relative humidity, carbon dioxide, light, ambient sound and atmospheric pressure in a home.

"Measuring the environment of your house or other property is not expensive, but it is important to your health and the condition of the property. We wear smartwatches and activity trackers for ourselves. Get one for your property."

3. Open doors and windows

"You hear this daily, but there is no substitute for open your doors and windows, and not just one either. An open window at each end of the property helps create a healthy environment," Van Blerk says.

Heating, ventilation, and air conditioning (HVAC) systems – preferably those with a balanced heat recovery – are also an option for those that can afford them.

For more information visit:


Tether is the first building performance insights platform that makes it easy to have full visibility of a buildings operating efficiency and environmental impact through data driven insights. Through Tether you can now make the changes needed to give you significant savings, improve health and contribute to a more sustainable planet.

At first, self-funded upwards of a quarter of a million dollars by majority shareholder and CEO, Brandon van Blerk, Tether is a tech start-up company that offers a turnkey, full-stack solution for solving building performance problems through real-time monitoring and data-driven insights. Tether closed a successful $1.75m seed funding round in August 2021 and as a result brought on the Impact Enterprise Fund (IEF), NZ Growth Capital Partners (NZGCP) and Greenside Energy Solutions as strategic partners and investors.

The vision for Tether started in July 2017. By October 2017 the company had its first prototype solution and signed its first contract with Tamaki Regeneration in February 2018, before being rolled out to Housing New Zealand properties in June 2018. Tether now have an extensive list of impressive customers that include government bodies, research agencies, building performance experts, architects, and property management companies.

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