Houzz Tour: An Energy-Efficient Home for 3 Generations
This Australian house takes sustainability and accessibility to a new level
There are three pillars of sustainability we should aim to balance when building or renovating. Many of us concentrate only on economic sustainability — keep that budget in check or you might end up with a hefty mortgage and only half a house. The eco-friendly warriors among us might prioritize environmental sustainability instead — tread lightly or suffer the wrath of Mother Nature. But while economic and environmental sustainability are crucial, there is also social sustainability to consider. This means a project should be inclusive and not displace the wider community.
The house seen here encompasses all three pillars of sustainability, for an energy-efficient, mid-priced home that’s also wheelchair-accessible. Trifecta!
The house seen here encompasses all three pillars of sustainability, for an energy-efficient, mid-priced home that’s also wheelchair-accessible. Trifecta!
From the outside, this house looks like any modern home, and in many ways that’s the beauty of the project. It demonstrates that an environmentally sustainable home needn’t look any different from other houses on the street. The fact that it fits in is an example of social sustainability — the home doesn’t dramatically alter the character of the neighborhood.
The use of readily available materials and standard building techniques helped rein in the cost, checking the economic sustainability box. At first you might not notice the gradual slope or the width of the path to the front door, but that’s a hint that the home is also wheelchair-accessible. This is a multigeneration residence where the owners’ parents also live.
The use of readily available materials and standard building techniques helped rein in the cost, checking the economic sustainability box. At first you might not notice the gradual slope or the width of the path to the front door, but that’s a hint that the home is also wheelchair-accessible. This is a multigeneration residence where the owners’ parents also live.
Inside, the home is surprisingly light and bright. Though the house recedes deep into the lot, clerestory windows in the living area help light reach far inside.
The ground floor consists of a shared open-plan living, dining and kitchen area, which opens onto a sunny north-facing backyard. The space serves as a hub where all three generations of the family gather for meals, relaxation and entertainment. The grandparents’ bedroom, with en suite bathroom, is also on the ground floor for easy accessibility.
The ground floor consists of a shared open-plan living, dining and kitchen area, which opens onto a sunny north-facing backyard. The space serves as a hub where all three generations of the family gather for meals, relaxation and entertainment. The grandparents’ bedroom, with en suite bathroom, is also on the ground floor for easy accessibility.
In fact, everything on the ground floor is designed with accessibility in mind, making it easier for the grandparents to navigate. Flowing spaces in the kitchen, dining area and pantry, wider-than-standard doors, a cantilevered kitchen counter and low electrical outlets all take wheelchair maneuverability into account.
Above all, the owners wanted “a home that was energy- and water-efficient to minimize bills, and was in line with how they felt they should be living on the planet. That is, one that is as low-impact as possible,” designer Chi Lu of Positive Footprints says.
The owners also wanted lots of light and warmth in the home, so measures were taken to provide that in the most eco-friendly way possible. The home is designed to be passively warmer in winter and cooler in summer. A reverse recycled-brick veneer wall in the living area, along with polished concrete floors, help moderate the home’s temperature.
The challenge was to bring the winter sunlight deep into the rooms farther to the south, Lu says. “The solution was to create a tiered design with a raised central clerestory, to bring northern light deep into the belly of the house,” she says. “This means that it heats quickly when the sun comes out in winter.”
In summer, the concrete and brick help the home stay cooler, and the higher-angled sun is blocked by carefully designed eaves. At night, opening the clerestory windows and turning on the ceiling fans draw in the night air and capture sea breezes.
The owners also wanted lots of light and warmth in the home, so measures were taken to provide that in the most eco-friendly way possible. The home is designed to be passively warmer in winter and cooler in summer. A reverse recycled-brick veneer wall in the living area, along with polished concrete floors, help moderate the home’s temperature.
The challenge was to bring the winter sunlight deep into the rooms farther to the south, Lu says. “The solution was to create a tiered design with a raised central clerestory, to bring northern light deep into the belly of the house,” she says. “This means that it heats quickly when the sun comes out in winter.”
In summer, the concrete and brick help the home stay cooler, and the higher-angled sun is blocked by carefully designed eaves. At night, opening the clerestory windows and turning on the ceiling fans draw in the night air and capture sea breezes.
Reverse brick veneer construction, seen here, is the opposite of the typical brick veneer house, which has the bricks on the outside and lightweight drywall inside. The latter method is great for durability, but it wastes bricks’ inherent thermal mass properties.
By flipping the bricks to the inside and using corrugated iron, fiber cement siding or clapboard outside with a layer of insulation between, the home has far superior thermal performance, meaning less energy waste, a more comfortable home and lower utility bills.
Anatomy of a Brick Veneer Wall
By flipping the bricks to the inside and using corrugated iron, fiber cement siding or clapboard outside with a layer of insulation between, the home has far superior thermal performance, meaning less energy waste, a more comfortable home and lower utility bills.
Anatomy of a Brick Veneer Wall
Large double-glazed bi-fold doors, which are thermally broken — they contain an element that lowers thermal conductivity — connect the interior with the backyard without jeopardizing the home’s thermal performance. Given that windows and doors are a major source of unwanted heat loss and gain, it makes sense to pay extra attention to the glazing. This design proves that you can have generous openings — really connecting indoors and out — while being energy-efficient.
Though concrete is often not the most environmentally friendly product to make, being carbon-intensive, it does have a number of benefits. Concrete’s mass helps store thermal energy, and it’s durable, so it requires very little maintenance and has a long life.
Lu and the team took steps to mitigate the downsides of concrete while drawing on its strengths, creating an insulated floor slab for the home. This “eco-slab” uses up to 60 percent cement replacement (utilizing waste products from other industries) and other recycled materials to reduce its ecological impact. In addition, recycled glass was seeded into the surface of the wet concrete, so the polished floor has a glimmer — a nice combination of style and substance.
Lu and the team took steps to mitigate the downsides of concrete while drawing on its strengths, creating an insulated floor slab for the home. This “eco-slab” uses up to 60 percent cement replacement (utilizing waste products from other industries) and other recycled materials to reduce its ecological impact. In addition, recycled glass was seeded into the surface of the wet concrete, so the polished floor has a glimmer — a nice combination of style and substance.
The stairs and upstairs flooring are bamboo, a sustainable alternative to wood since it’s a fast-growing grass whose shoots are harvested without killing the plant. A bright yellow wall in the stairwell helps liven up what might otherwise be a dark space.
Upstairs are the parents’ bedroom, the children’s bedroom, a bathroom, the play area seen here and a spacious deck. “While the ground floor and garden make sure that there is plenty of shared time between the generations, the upstairs provides a retreat for the young family when required,” Lu says.
To counteract the fact that warm air rises, special phase-change sheets were installed behind the drywall to help keep the second floor cooler in summer.
To counteract the fact that warm air rises, special phase-change sheets were installed behind the drywall to help keep the second floor cooler in summer.
You can’t tell from this photo, but that lush-looking lawn is hiding a secret weapon in the home’s environmental sustainability arsenal. Ten feet below the surface is a looped pipe, an “earth tube” cooling system. It uses energy-efficient fans to draw warm air out of the home and underground, where the soil stays at about 64 degrees Fahrenheit. The lower temperature of the ground chills the air, which is then returned to the house.
A greywater recycling system, which helps keep the lawn green, also increases the conduction of heat from the earth tube. This cooling system was one of the biggest challenges of the project.
“As there is no such thing as an off-the-shelf earth tube cooling system, it needed to be designed from the ground up, using logic, common sense, Internet trawling and a fair bit of try-it-and-see,” Lu says. “Fortunately it has been successful.”
A greywater recycling system, which helps keep the lawn green, also increases the conduction of heat from the earth tube. This cooling system was one of the biggest challenges of the project.
“As there is no such thing as an off-the-shelf earth tube cooling system, it needed to be designed from the ground up, using logic, common sense, Internet trawling and a fair bit of try-it-and-see,” Lu says. “Fortunately it has been successful.”
A framework was erected along this east-facing wall as a support for climbing plants. In addition to being beautiful, the creepers will eventually shade the wall from the brunt of the morning sun.
Raised planter beds in the backyard, used by the family to grow organic produce, are at a good height for wheelchair-accessible (and back-friendly) gardening.
From the sunny backyard you can see some of the equipment that helps make the home eco-friendly. A rainwater tank provides water to the toilets and laundry. Solar panels on the roof help power the home. You also get a good sense of how the eaves help keep the sun out during summer, and how nice the connection between indoors and outdoors is when the bifold doors are open.
While most of the energy efficiencies come from the nine-star passive design, an integrated building-control management system designed by MacTech operates the home’s active systems to ensure peak performance. It has the ability to open and close windows, turn on fans and operate the earth tube cooling system to ensure the home maintains a comfortable temperature.
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Who lives here: Two grandparents, two parents and two young children
Location: Seaholme, Victoria state, Australia
Size: 2,475 square feet (230 square meters); three bedrooms, two bathrooms
Designer: Positive Footprints
That’s interesting: The home has a nine-star energy rating, and the ground floor and garden are wheelchair-accessible to cater to the elderly grandparents.