Home Ventilation Competition Hots Up
A unique ventilation system, now produced commercially, reduces unwelcome condensation and keeps homes drier and
healthier at a quarter of the cost of competitors.
Auckland electrical engineer John Wadsworth designed and built the ductless unovent home ventilation system for moisture
reduction, and has patented it in New Zealand and overseas.
“This is a game changer,” says Mr Wadsworth, who established Unovent Limited in April this year. “Modern home
ventilation systems have been around in New Zealand for 18 years and they have always been done with a ducted system.
“Mine doesn't need ducting or a large fan in the cavity of the roof, and it's simple to install and maintain.
Importantly, it's just as effective in reducing moisture in the living areas and condensation on the windows,” he says.
Mr Wadsworth, formerly managing director of Honeywell New Zealand, developed a small, all-in-one vent and fan which is
operated by a 12 volt lightweight power cable. The unovent unit includes a filter which can easily be removed from
inside the room, washed and put back in place.
A standard three-bedroom house would have four units installed in the ceiling of each living area and are connected by
the cables running to power supply plugged into a 240 volt switched socket located in the roof cavity or in a cupboard.
The traditional home ventilation systems comprise a large central fan and filter cartridge installed in the roof cavity
and connected to a network of aluminium foil ducting which fit into ceiling-mounted room vents. The fan, usually between
80 and 200 watts, has to be big enough to overcome the resistance of the ducting and uses more power. The filter
cartridges have to be replaced every two years at extra cost.
The unovent kitset for a three-bedroom house (four vents and integrated fans and filters, power cabling and plug
connectors) costs $950 including installation and a comparable product is up to $4000, with installation taking one to
two days.
Mr Wadsworth's invention uses less than $1 worth of power a month; whereas a 200 watt fan will soak up that amount in a
day, creating a power bill of about $30 a month.
His system pulls dry air from the roof cavity and is mixed with the wetter air in the bedrooms, lounge and dining room,
thus reducing the moisture content in the living areas. This also reduces condensation on the windows and moisture being
absorbed into wall coverings, drapes and carpets which can lead to mould and mildew - key triggers for asthma and
allergies.
“As well as having a healthy home with fresh, filtered air, you save on maintenance since the water doesn't run down the
windows and rot the wooden surrounds, and the drapes or walls don't go mouldy and need to be replaced or repainted,”
says Mr Wadsworth.
The unovent system can be kept running all the time during the cooler autumn, winter and spring months and shouldn't
need to be used during the summer when condensation isn't an issue. The system has an optional thermostat which switches
the system off when the roof cavity air temperature reaches, say, 28 degrees Celsius.
Mr Wadsworth sees big opportunities for his home ventilation system. “Over the past 18 years about 250,000 systems have
been installed in homes in New Zealand. There are 1.4 million houses in the country capable of taking a ventilation
system and we've got 1.15 million to go,” he says. “The modern double glazed, airtight home needs the system even more.”
Sitting in his new home in Pakuranga, Mr Wadsworth decided there must be a cheaper and simpler way of getting rid of all
the moisture on his lounge and bedroom windows. He spent a year experimenting with three different ventilation mounting
systems before deciding on the all-in-one vent and fan unit, which his company produces.
Following further research and testing, Unovent now offers a SourceControl humidity controller which is set and
installed in the roof cavity to switch off the ventilation system during times of high humidity.
“The excess humidity of the roof cavity needs to be dealt with to avoid bringing the less helpful air down into the
living area,” says Mr Wadsworth. “This happens when we get many days, one after another, of rainy or drizzly weather -
even when the temperature outside and in the roof cavity is as low as 11 or 12 degrees Celsius.
“Most suppliers of home ventilation systems for moisture reduction never talk about this effect and what to do about
it,” he says.
Mr Wadsworth began producing his kitset home ventilation system in April this year and it has already gone into more
than 50 homes around the country.
Mr Wadsworth graduated from Canterbury University with a Bachelor of Engineering Honours degree, majoring in electrical
engineering. He was the branch manager for Hewlett-Packard in Auckland, group engineering manager for Holyoake
Industries (Australasia's biggest manufacturer of air management systems), and worked for Honeywell NZ for 16 years,
being managing director for most of the 1990s.
He was also director of Honeywell Pacific's sensing and control group, a fellow of the New Zealand Institute of
Directors, and was awarded the Paul Harris Fellow for leadership while a member of the Ellerslie Sunrise Rotary Club.
For more information visit www.unovent.com
ENDS