A new house on a rural block near Tarras has
underfloor heating and other mod cons, but the owners do not
expect to receive any power bills - ever. Mark Price
Duncan Kenderdine and Suze Keith with children Caitlin (11)
and Phoebe (9) have just moved into their off-grid home
beside the Clutha River near Tarras.
A Wellington family with a love of camping and roughing it on
Central Otago holidays have taken self-sufficiency to a whole
The family - Duncan Kenderdine, Suze Keith and their children
Caitlin and Phoebe, and Duncan's mother, Shonagh, have just
completed a 200sq m house that runs without relying on
It has all the usual electrical and heating devices of a
modern house - including underfloor heating and a dishwasher
- but the family have found other ways to make them function.
There are solar hot water-heating panels, photovoltaic
panels, batteries, a wood-burner with a wetback, an lpg oven
and fridge, a huge, heavily insulated hot water tank and, for
when all else fails, a large diesel generator.
A solar-powered pump keeps the water tank topped up. Photos
by Mark Price.
It is a far more complex house than the average, but the
family is confident it will provide all their energy needs
without having to pay for electricity from the grid.
Shonagh Kenderdine is a Dunedin-born former Environment Court
judge, now of Wellington, and is chairwoman of the New
Zealand Historic Places Trust.
Her son, Duncan, is a qualified architect who works for
Downer Group and lived in Dunedin while working on the Otago
Corrections Facility at Milburn.
For many years, the Kenderdine family had a small,
uninsulated cottage at Luggate - "a classic Kiwi bach",
according to Duncan.
But eight years ago they bought a piece of land on the bank
of the Clutha River near Tarras where, until now, their
Central Otago holiday accommodation was a small tin shed and
Duncan said, "It's a lovely way to be. Very simple, away from
A few weeks ago, they moved into their new straw-bale home -
still lacking many finishing touches, including its exterior
coat of cob - but operating independently off the grid.
The family's eight-year journey towards a house
self-sufficient in electricity began with the news it would
cost them $35,000 to hook up to high-voltage power lines near
"As we sit here in an off-the-grid straw-bale house wasn't
where we started," Duncan said. "Being super-sustainable
wasn't the driving force. It's just where we've ended up."
Part of their thinking was to make use of Central Otago's
high sunshine hours.
That led to the installation of an evacuated-tube solar hot
water system and an array of photovoltaic panels on the roof
of the garage, angled for the winter sun, with a battery bank
below and a "pretty serious" diesel generator out the back.
"You could be quite brutal about it and say, well, you are
just going to have the photovoltaic system and no backup, but
last week the average temperature for five days was -3degC
and it was cloudy."
Mr Kenderdine said the photovoltaic panels were in place
before work on the house began and on some days, full
construction was going on with people using saws and concrete
mixers, all running off the panels.
Their hot water system, which also heats the house, cost
The photovoltaic system with six panels and six batteries,
including the generator, cost about $30,000.
But Mr Kenderdine said every time the price of power from the
grid went up, the payback period for their system became
He did not expect the technology they were using to be
"You've got to be prepared for a long-term return. So if you
are looking to sell the house in four years, you might not do
it, because you don't get the return."
Ms Keith describes being off the grid as "exceedingly
"It's a really nice feel and the straw bales are an
exceedingly nice environment to live in."
The family are quite relaxed about having to balance their
use of energy between heating water, heating the house and
running appliances, and liken it to the decisions that come
naturally while camping.
They have had little experience living with the systems yet.
Ms Keith says with a laugh that, some days, the choice might
be between being "smelly but warm" or "clean but a little bit