IT IS no ordinary renovation project. Beneath the surface of this Point Lonsdale property lie a series of deep holes that will harness a unique resource — the heat of the Earth itself.

Fitted inside these bores, reaching depths of up to 30 metres, are copper loops that will tap into this geothermal energy and use it as an alternative to traditional heating and cooling systems.

It works by tapping into the temperature below the frostline, which remains at about 12 degrees all year round.

Refrigerant fluid in the pipes will draw heat out of the Earth in winter, and send heat from the air back to the ground in summer.

"Nature's got it all worked out," explains project leader Donald Payne. "Another way to access this would be to all live in our basements and not have any view. This is a way of still being above ground but having the benefits."

The geothermal system, due to begin operating at the property next month, is expected to bring energy savings of up to 70% compared with a conventional air-conditioning system.

And while the set-up costs are greater — costing more than $1000 to drill each bore (in this case there are 12) — it is tipped to pay for itself through reduced energy bills within three to five years.

The development at Highfields, an old cattle property being transformed into a model for sustainable living, is one of the latest projects making the most of Victoria's geothermal energy resources.

While much attention has been on the possibilities for geothermal power — driving water on to hot rocks several kilometres underground and using the steam to produce electricity — the use of geothermal energy as a heat source is becoming increasingly popular.

Energycore, the company behind the Australian-first technology at Highfields, also has projects under way at council offices in Corryong, a farmhouse near Cranbourne, and this week started digging holes for a Narre Warren factory block.

The idea of using the Earth's own warmth as a heat source is not new, but Sustainability Victoria's John Osborne, project manager in renewable and distributed energy, says all forms of geothermal energy are now "starting to take off".

"Once a few people have installed, others will come in," he said.

http://www.sustainability.vic.gov.au/