Designing a 7-Star Energy Efficient home

DESIGNING A 7-STAR HOME

THE BUILDER AND THE SCIENTIST

Mick Fabar, CEO, founded Green Homes in 2006, an international, sustainable design and construction business that has seen remarkable success since its beginning. In the earliest days, he enlisted the help of engineer and ecologist, Ash Bland.

“We’ve grown into a brand that operates in Australia, New Zealand, and the U.S. We’re globally certified in our principles and our training and processes of designing, delivering, and constructing an energy-efficient home,” Mick says. And their success has brought with it experience and knowledge, and some surprising insights.

“Building a green home doesn't have to cost the earth. These are principles that we should all apply, and which are just so achievable,” Ash says. Despite what many people think, a high-performing home can be built for a very small margin more than the less efficient alternative.

“It’s around 2 to 3 percent,” Ash says. All it takes is prioritising energy efficiency. People will drop ten grand on a benchtop yet worry about ten grand on a better quality of glazing,” Ash says. “But it’s that glazing, among other things, that can make for a comfortable, energy-efficient home that’s great to live in.”

DESIGNING A 7-STAR HOME

7-STAR RATINGS EXPLAINED

“The star rating indicates the balance of the energy that goes in and out of that home. It’s based on the amount of energy you have to add to maintain thermal comfort between 19 and 24 degrees,” Ash says.

Since the star rating is determined by how much energy is needed to keep a home comfortable, the less energy required, the higher the star rating. And the more energy required, the lower the star rating. And while only one number higher, the change is a significant shift.

”In parts of Australia with mild weather, 6 stars has been reasonably easy to achieve, even with poor design. But for 7 stars you really need to think about thermal performance up front,” Ash tells us. And this performance is influenced by essential elements in the design and build of the house – some that can’t be overlooked.

DESIGNING A 7-STAR HOME

ORIENTATION IS NUMBER 1

“The first question you must ask is: ‘How can I use the natural conditions to heat and cool my home for free?’ Wherever you are in Australia, that's what you should be thinking,” Ash says, “The answer to this will influence the orientation of the home.”

Choosing the orientation of your home – including window placements – based on its location and climate is the single most crucial part of designing a 7-star, thermally efficient home – it’s the first step that shouldn’t skipped.

“If you live somewhere that gets hot, you need to think of how to keep that heat out of the home. And if you live in a coastal area, consider how cooling breezes can be optimised. Plus, in colder climates and with winter in mind, it’s essential to look at how to use the sun's energy to heat your home for free,” Ash says.

“From that point, you can start looking at things like insulation, thermal mass, shading, and finesse from there,” Ash says. “But if you get that orientation wrong, you can never make up for it.”

DESIGNING A 7-STAR HOME

MATERIALS MATTER

When it comes to materials, the most crucial measure is performance. However, if your sustainable approach extends to how the materials impact the environment beyond your home’s performance, extra consideration must be made here.

“Once you start to get into material selection, you're starting to talk about environmental impact and lifecycle analysis,” Ash says. But to build to a 7-star rating, it boils down to performance, and that’s measured in R-value, known as a thermal resistance rating.

“You just want a high R-value in your walls. It doesn't really matter what they're made from," says Ash. “As long as you meet the principles of physics and performance, the material performance itself can be achieved several different ways.” And one way to achieve a given R-value is by incorporating the right insulation correctly. Insulation is key.

DESIGNING A 7-STAR HOME

HOW WINDOWS MAKE THE DIFFERENCE

"Windows play a huge role in allowing heat in and preventing heat escaping. We need to have windows in the correct locations and made of the right material so we can control those elements,” Mick says.

“Heat loss or gain through walls is marginal compared to the windows. Even though windows take up a relatively small proportion of any room, they can account for the greatest amount of heating or cooling, in or out,” says Ash. “By putting in proper glazing, you will save a lot of money on your heating and cooling costs. It's often the single biggest thing you can do that will make a material difference to the comfort of a space.”

And this is where, as Mick mentioned earlier, the right products come in. Green Homes are proud to be working with products from Trend in their builds.

“From top to bottom, they get it. They're as passionate about sustainable homes as we are,” Mick says.