In these days of spiralling energy prices, how a home is built can make all the difference when power bills arrive, with their growing impact on the household budget.

The Illawarra Flame has been granted exclusive access to one of the nation's most energy-efficient homes, created on the Southern Highlands and boasting a 10-star passive solar energy rating. The home's owners want to remain anonymous, but with a lifelong passion for the environment and protecting the planet, they're keen to share their experience in the hope it might encourage others to  create more liveable homes.

This story and the ground-breaking project has had a long gestation period, dating back to 1997 when the family identified the ideal location on an acreage.

Bringing a 30-year plan to fruition

"It took us nearly 30 years to plan, design and prepare the site for this project, but it's been well worth the wait," said the owners. For the purpose of this story, let's call them Max and Dawn.

"There were no trees on the property when we bought it, essentially it was an open paddock," Max said.

So in the year 2000, they started planting with the aim to have an established garden when they were ready to build and move in.

It was a whole two decades later, after much consideration and a change in architect, who truly understood and shared their vision, that construction began.

"We decided to move up here from the South Coast to beat global warming. It's six degrees cooler up here," Max said. The heating and cooling of their home is such a key to their new life on the highlands. 

As well as their desire to create a home that has a minimal impact on the environment, another important aspect of the home's design was to provide enough space to accommodate three generations of the family in the same place. But more on that later.

Those early plantings, now fully grown, today provide a wonderful mature garden, a mix of deciduous and native trees. In planting the garden, one of the main goals was to create a microclimate within which to build the family home, and the planting of a strong windbreak to protect the property from the prominent southerlies and westerlies has done just that. It was also important to leave the northern side of the home as a protected sunny lawn which allows unimpeded solar access to the home.

Creating the ultimate energy-efficient home

Then came the layout and design for the house, and just as importantly, decisions about which materials to use and how to use them to create the ultimate energy-efficient home, and with it, desirable comfort without the need for much cooling or heating throughout the year.

"We had all the concepts in our mind. We knew all the principles," Max said. "It's not a complicated process if you follow the principles."

The other non-negotiable for the home builders was to create a building that would stand the test of time, a natural enough desire given this property is multigenerational.

"We confidently believe this house will last 200 years," Max said proudly. 

The key to the home's layout is its orientation. It has a long, north-facing elevation that captures the maximum winter sun, and its slender design means it minimises the impact of the hot western sun in summer.

"It's free solar energy," Max said. "Every living room and bedroom has a full ceiling to floor northern wall of glass (double gazed) with no outside shading. Because it's so well insulated, the home heats so quickly. This morning it was 11 degrees outside and 21 degrees inside with no artificial heating."

The home's exterior uses lightweight materials and is light in colour to absorb less heat in summer. The stone block work absorbs the sun's heat and then gradually releases it back into the home.  Inside, the use of slab ground flooring, and brick, stone and concrete helps store the heat during winter, reducing the need to heat artificially.

A home that's liveable all year round

"If you work the house right, it's still very liveable year-round. As long as the sun's out the temperature inside comes up to 22 degrees. The key is, once you have got the heat in you keep it through the thermal mass of the masonry inside," Max said.

"We rarely need to light the fires in winter. We also have very good insulation, which is packed so well without folds or gaps."

Verandahs and garages have deliberately been located so as not to impact on solar access.

Purpose designed and built for Max and his family, the spacious single-level home sits beautifully in the leafy landscape. 

While its 10-star rating achieves the aim of creating a comfortable home that ticks all the boxes for energy efficiency, it also meets the needs of a family growing old together in a little piece of Southern Highlands paradise.

The main house is split in three.  Max and Dawn's  bedroom, kitchen and living space can be sealed off from their daughter and son-in-law and their kids, with a central shared space available for everyone when the family wants to come together.

Max says everyone has embraced the concept of multigenerational living. "It's how most of the rest of the world has always lived. It's just us westerners who haven't quite got it yet."