Habitat 15 - State of grace
Habitat 15 - State of grace
Using eco-friendly design ideas in a new home is relatively easy but what about a renovation?
State houses are built to honour certain principles - to give anyone, no matter what their income, a quality home in which to live. Now one of those earlier homes, tucked into a quiet corner of Auckland, has been renovated to honour a different set of principles - to be as energy efficient and therefore as eco-friendly as it can be.
Early state houses were certainly solidly built, often of brick and native timbers, on generous sections. They may have been highly functional, but they sometimes weren't that comfortable, lacking insulation and good sun orientation.
Many older state houses have now passed into private ownership and have been renovated. When Eddie and Hilary van Uden planned the renovation of their ex-state 1940s house in 2009, they chose to make it as 'green'as possible. As a way of measuring how successful their eco-renovation has been, Eddie assessed it with a new rating system called Homestar which gauges a home's energy efficiency (see box overleaf) and other sustainability features. The original house scored two out of 10 and the renovated and extended house now scores seven.
As an architectural designer with his own company Equinox Design Ltd, Eddie has had an on-going passion for 'green' building. The renovation of his own home was the ideal opportunity to show what could be done, no matter what era the house. Using eco-friendly design principles on a new home is relatively easy with the ability to incorporate features such as passive solar (sun orientation, shade control, storage masses like concrete floors or walls), cross ventilation, high-grade insulation, solar panels and more from the outset. But to retrospectively add these to an old house is more difficult.
The van Uden house was essentially a small brick box. Additions were made to the front and back to give extra living space, a home office, main bedroom and a garage. To improve wall insulation, the bricks were removed, insulation added to thicker-than-usual walls, and the entire house wrapped in a fibre-cement wall underlay and reclad in timber weatherboards.
One of Eddie's principles was to reuse as much as possible so that little waste left the site. The bricks were used to create a new driveway and paths, and to build raised vegetable gardens. All soil excavated from the foundations was reused on site. The old roof tiles, timber joinery, hot water cylinder and oven were sold on TradeMe.
Most of the demolition plasterboard was buried on site. All of the old concrete from the driveway and paths was either used as fill under the concrete slabs or buried on site. The old kitchen cabinets were re-used in the new workshop at the back of the garage.
A key goal was to incorporate passive solar design. The additions were built on solid concrete foundations and the floor slabs covered with tiles, which gives the vital solid mass required to capture the sun's warmth during the day, and slowly release it at night.
Big sliding doors and windows were added to the north-facing side of the house to let in as much sun as possible, with the house eaves built to the right depth so that hot summer sun is blocked yet winter sun is allowed in.
Says Eddie: 'It's such a comfortable house. In summer indoor temperatures stay below 25°C even when outside temperatures reach 29°C. On sunny days in mid-winter, the living area temperatures seldom drop below 20°C, even if it is below 10°C outside. The house is much drier and there's never any condensation on the windows.'
All window joinery is now double-glazed, water tanks were installed to collect rain water to use in the toilets and garden, solar panels were added to help heat the water, a wood burner installed and energy efficient appliances chosen.
Timber ceiling battens were used; steel battens are now more common but transfer electromagnetic fields throughout the house as lighting wiring is draped over them, says Eddie.
Low VOC Environmental Choice paints by Resene in Resene Quarter Lemon Grass, Resene Alabaster and Resene Pohutukawa were used throughout the interiors.
The 'green' approach also extended outside, with a back garden now dominated by fruit trees and raised vegetable gardens. Two fruit-laden persimmon trees grow alongside the deck while the original rotary clothesline lazily spins in a sunny corner.
The van Uden's electricity use now averages less than 10kwh a day (which includes running a home office) with a total consumption of less than 3600kwh for the first year. This is less than half the average for a normal two-person household. 'We're now cosy and content,' laughs Eddie.
Average water consumption is down to 170 litres per day (Watercare states two-person households as averaging between 225 and 401 litres a day).
That champion of the state house movement, the first Labour Prime Minister Michael Joseph Savage, would no doubt approve.
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