An alternative to solar hot water heating

[marsden_online]

Use a heat pump to grab the heat generated in your roof space. Via IdeaLog (about halfway down the article)

David Senn is the classic Kiwi tinkerer. In only five years he took his Econergy heat pump design from a garage in Ardmore to winning last year’s Consumer NZ DIY Product of the Year.

Now, according to the University of New South Wales, anyone currently using an electric boiler could save up to 69.4 percent on hot water heating by switching to an Econergy HP4000LT heat pump, which transfers energy from the air in your roof space.
...
The results, according to Consumer NZ’s Bill Whitley, are world class. "The Econergy HP4000LT was the star of our heat-pump water-heater test, blitzing its competitors,” he says. “Our test found that Econergy, a locally designed and made product, was at least three times more efficient than a standard electric cylinder. It’s on a par with solar power in terms of energy savings—and is likely to outperform solar in less sunny parts of the country."

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Also in green news from IdeaLog: The sustainable high-rise building material of the future - wood. (And a real opportunity for NZ to export value-added product instead of raw material)