Greens Beach Solarhome to open doors to the public

On a stormy day in Greens Beach, when the power was out across the town, the residents of the Greens Beach Solarhome were none the wiser.

We walked in and owner and designer David Macfarlane offered us a coffee like there was not an issue in the world.

His neighbours, on the other hand, had been without power for hours as a result of wild weather and trees falling on to powerlines.

His home is the only fully off-grid house, that he knows of, in Australia and he has done two years of study to help him make that claim. He also cannot recall another house this off-grid in the world.

“Other ‘off-grid’ houses are kind of like a hybrid car which has been taken to the next level. The next level is an electric car, but you still have to plug that in to charge,” Mr Macfarlane said.

“This one has been taken to the next level again where you never have to re-fuel it or ever recharge it. That’s what I was trying to achieve.”

While studying, Mr Macfarlane tried to find a house that could say it was genuinely emission free. 

“I could not find anything, anywhere, because all of them have a connection so they suddenly can connect if they need to,” he said. 

Once every 20 years the house will require a new battery. It is cyclone and bulletproof, fire resistant, doesn’t have any gutters that need cleaning, and rain drains from the concrete roof in to tanks. 

There are no power bills, and no back up to the power lines, because Mr Macfarlane said the aim was show it is quite possible. 

“It’s completely maintenance free. It’s off-grid for water, and for the sewerage,” he said.

“To be honest, most people don’t even know that there is no power connection. And that’s the way it should be. 

“Even with the power too, if you turn everything on, nothing flickers. It’s more stable than a grid connection.”

Mr Macfarlane had spent a number of years building houses, before he ended up working in tourism on an island in the Whitsundays for 14 years. Then he decided it was time for a change. 

“So I went over to the UK and studied a masters in sustainable building design over there for two years,” he said. 

Since studying, he has been working on making this plan come to fruition. 

He said houses like the one at Greens Beach are often done in Germany, but always had some sort of back up. 

The house was designed by Launceston’s own Martin Dingemanse of MODE Electrical.

“When I went to Martin and said this is what I want to do, He didn’t really think it was possible, and neither did I,” Mr Macfarlane said.

Mr Macfarlane said he didn’t want a house that he had to be “careful in”, he thought why not try it and see what happens. He said it is living proof that it’s possible.

“When you go to a guy like Martin and the first thing you tell him is it has to be off-grid and he says ‘yep, sure, solar panels, battery and a generator’. And I said ‘nah, no generator’,” Mr Macfarlane said. 

“And he said ‘OK – solar panels, batteries and gas for cooking’. I said ‘I don’t want any gas and I want to heat it off the electricity as well’. He said ‘geez, OK’.

While he admits it was not a cheap process, he said it’s a very clever system and not overly complicated.

He is an avid lover of Tasmania, but it was the state’s testing climate which made him build the house here. He even lived in the house for the first 12 months to put it through its paces. 

“This wouldn’t be that hard to do where it’s not that cold in winter, but I deliberately looked for somewhere that was going to be a real challenge for it,” Mr Macfarlane said. 

The house is “not that complicated” and “dead simple”, he said.

“It’s triple glazed windows, R-8 insulation, which is a lot of insulation, and it’s air-tight. So there is no air leakage. It has ventilation system so there is fresh air coming in. It’s a small volume, so you’re not having to heat a lot of air.”

The 66kw batteries that run the house are worth $20,000 and are expected to last 20 years depending on how hard they have to work. 

“The battery’s lifespan depends on how far you cycle it down. If you drain them down to 50 per cent every day they last eight years,” he said. 

“These batteries very rarely get below 80 per cent so they’ll last about 20 years. Even with everything left on, it still wouldn’t go flat. Even on overcast days it’s still taking in power. But in 20 years, the batteries won’t be as big as they are now and they won’t cost that much.”

The house has 25 solar panels all together, with 17 on the house and another nine on the carport. 

“About half the panels feed directly into the house, so it’s not even coming off the battery. If it’s sunny you can go for ages and the battery is just 100 per cent all the time,” he said.

“All of the stuff that is running during the day is just going straight off the panels. So that’s just adding years and years to the battery. It’s very clever.”

The whole power system cost about $50,000 in total.

“When people ask about the power system and I say ‘$50,000’, they always go ‘meh’. And I always say to them well why didn’t you ask about the driveway and the carport, because that cost $50,000, too,” he said. 

“The biggest challenge at the moment is that people think batteries, off grid, I’m going to have trouble.

“The whole motion of this was to show that you don’t actually have to worry and that’s why I lived in it for 12 months.”

Mr Macfarlane has bought the land next door to the Solarhome and plans to build a “more affordable” version next door. 

“It’ll be a timber-framed version of this, which is just a little bit cheaper to do. It will be lighter weight and won’t have the cyclone proof with it,” he said. 

“It will be a more standard sort of design, but with still the same energy format.”

Mr Macfarlane, who is based in Sydney, plans to keep developing the idea to sell.

On September 16, he will open the doors of the Greens Beach Solarhome to the public. 

“It’s just to show people what can be done and to see if there is any interest locally,” he said.