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Using the Earth's core to heat a home may seem impossible, but a Queenstown heating engineer says it is possible and has been for more than 60 years.
The Central Heating Company's heating engineer Albie George said the heating systems cost "a fraction'' of what standard heating systems cost to run, and used energy that escaped from the earth every day.
‘‘The heat from the core heats the crust to a constant 10degC year-round,'' Mr George said.
‘‘Usually, that escapes into space but we are installing 60m probes into the ground to collect some of that energy and use it to heat a home.''
The systems started at $28,000 to install, but Mr George said they paid for themselves within five years.
‘‘Or less if the price of fossil fuels keeps going up,'' he said. The rising cost of traditional heating systems was generating a lot of interest in geothermal heat, he said.
‘‘Some people around Queenstown pay $2000 a month for diesel-based heating in winter but this geothermal system costs around $1500 a year,'' he said.
‘‘For every kilowatt [of electricity] you put in, you get three out. If you are building a house, then you would be crazy not to install one of these.''
The technology had been around for more than 60 years, and a similar water-based variant was installed in London's Royal Albert Hall in the 1940s, Mr George said.
It collected heat energy in the ground and channelled it to a heat pump where the energy and compression intensely heated and vaporised water inside the unit.
The vaporised water then heated air, which was pumped through the home and also used for heating water.
The probes being installed today on an Arrowtown property were made to order and took six months to arrive from Germany, Mr George said.
Two 80m-deep holes would be drilled and the probes installed and connected to the house.
Ordered three months ago, the heat pump unit was due in the next six weeks.
Another revolutionary project, designed with Insitute Architecture's Hamish Learmonth, would heat the home and cool it in summer.
As it was the first geothermal heating and cooling system in the world, Mr George said people from Germany were coming to see how it worked.