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Everything you need to know about environmentally sustainable design – from basic principles to maximising performance

The sustainable design

Having been successfully emancipated from the domain of “hard-core greenies” into the psyche of mainstream Australia, environmentally sustainable design (ESD) principles are having a progressively deeper impact on the very make-up of the country’s contemporary luxury homes and communities. Admittedly, clarion calls from designers to create homes that deploy ESD principles, such as passive solar, good site orientation and cross ventilation is nothing new. But spiralling energy/water costs, state-based building codes — and renewed interest in saving the planet — have imbued Australians with a newfound respect for more holistic sustainability when it comes to 21st century home design. Having progressed from being purely compliance-driven, there’s now a broader recognition that by allocating up to 10 per cent of a design/build budget on sustainability, homes will be more comfortable to live in and cheaper to operate.

Maximising performance
According to Bruce Fyffe of Fyffe Design Services, the hallmarks of ESD-designed homes combine time-honoured first principles, such as good site orientation with an innovative use of space and materials/fittings that require less embodied energy to produce, while minimising the power needed to heat and cool. He says sustainability is indelibly compromised when a house is forced onto a site. “It doesn’t cost to customise a home design that will use the elements to maximise overall house performance,” says Bruce. With grown-up kids having fled, Bruce and partner recently decided to simply their lifestyle by rebuilding and downsizing into a 240sqm family home in Sydney’s Castle Hill with just one living area. But with one eye on a future resale market, they decided that sacrificing a bedroom for an additional living space was a prudent move. By using a 1.6-metre-wide cavity sliding door, Bruce is able to create one large living area — leading to a generous al fresco — that can be split in half, depending on who is living in the house. By combining 2.4-metre-high doors and windows with clerestories above, north-facing living areas can maximise winter sun, while extended (705mm) eaves minimise the effects of summer heat. “Due to good overall design, brick veneer with lightweight cladding, low-E lighting, good site orientation, and one central living zone, our power bills are a fraction of what they were,” says Bruce.

Back to basics
After 43 years designing homes, it still surprises Fred Miniter of Pratt Miniter Constructions how many “so-called” experts still overlook the basics when designing both high-end and less prestigious homes. According to Fred, most designs fail to get the fundamentals right on the basic stuff such as site orientation, insulation, and convective air flow. When buying land he recommends always trying to get north into the backyard to capture winter sun, and that means taking the time to understand the site and observe the typography. He says a good litmus test for any good designer is asking them how they’re going to get winter sun into the house. Before working out the fabric and roof coverings, Fred says it’s equally important to ask designers where the winter wind and summer breezes will come from that will ventilate the house via any courtyards and properly positioned windows. Similarly, he warns that bad advice, especially around all-important insulation, can be highly damaging to a home’s overall performance. “In recent years we’ve seen the emergence of houses without eaves. While this saves building costs, it allows the home to become more uncomfortable when summer arrives,” says Fred. “Lack of eaves overhang, combined with insufficient insulation to the wall cavity, can cause discomfort to the owner and a subsequent increase in power demand.” While sustainability doesn’t have to be majorly expensive, he says it’s important to ensure the choice of insulation actually does minimise and not compound the need for artificial heating or cooling. “Unbeknown to many, the clever use of foil can achieve the same outcome as bulk insulation, only more cheaply,” says Fred.

Design responses
Taking design response to prevailing typography to new heights is the Wilson house, located at Flinders on Victoria’s Mornington Peninsula. Designed by Sustainable Built Environments (SBE) to maximise environmental performance — by placing north-facing double-glazed windows sized to meet the house’s internal thermal mass — the Wilson house captures southerly views over Western Port Bay without affecting thermal performance. Anchoring the house to the site is a circular entry centre point which connects to threemetre- high insulated curved walls. Constructed of insulated rammed earth, these walls create an earthy spine that the house flows off to capture the 180-degree views of Western Port Bay. In addition to R7 insulation in the roof and R3.5 in walls, numerous other energy-and waterefficient home features that balance quality and view with environmental performance within the Wilson house include: evacuated tube solar hot water system, 40,000 litre of rainwater tanks, reverse brick-veneer walls, and hydronic heating linked to a combination boiler boosting the solar hot water.

Earthier palettes
Admittedly, many sustainable initiatives such as insulation and site orientation aren’t always easily noticeable at first glance. But when it comes to looks, what James Cooper of Sanctum Design is witnessing is luxury homes that, like the Wilson house, resonate with much earthier palettes. “We’re now seeing recycled timbers and natural materials such as hardwoods and stone, plus simplified finishes being set in a contemporary context along with an ever-widening array of modern external fabrics,” says James. Rather than being seen as a burden, James says “holistic sustainability” is now regarded as a function of good design process. Once seen as the bolt-on goodies or afterthoughts, he says solar power/heating and water collection are now “front and centre” in the sustainability stakes. What clients are now looking for at the mid to high end of the luxury homes market, adds James, is energy and resource security. The net effect is an “en mass” gravitation towards solar hot water, and PV (photo voltaic) solar electricity capacity. “There’s a perception that both regional centres and capital cities alike will experience power stress on the grid,” says James, “which only accentuates the risk of future blackouts.”

Securing supply
According to James, the “smart people” are investing in the security of their own solar hot water, PV solar power and water supply. With constant affordable services now seriously in question, he says people expect more frequent and potentially deeper utility cost increases, especially once there’s a price on carbon. “By reducing reliance on mains supply, people are underwriting their own access to services,” says James. In response to this new dynamic, much of his time is spent designing homes that deliver a “zero net” energy outcome. Interestingly, the idea of using active resource efficiency to produce as much energy as is used annually is no longer the exclusive preserve of residential homes.

Residential developments
The six units within an award-winning, sustainable townhouse development, Jarrah, designed by Sanctum at Lane Cove on Sydney Harbour, each boast generous PV panels and 10,000 litres of water storage connected to toilets and external taps to reduce potable water consumption. With 2.5kW of power per unit, or 16kW across the entire development, there’s sufficient energy to support the mains supply to ensure power bills are at worst minimal, claims James. Through thorough research, he says he was able to push well beyond “greenwash” lip service and take the sustainable outcomes within this mainstream townhouse development to new levels. By using recycled paving bricks and timbers extensively as feature cladding, together with lightweight timberengineered products, James says it was possible to deliver affordable solutions. In addition to a highly insulated building envelope, including R2.5 to walls and R3.0 to ceilings — to prevent heat from entering and escaping the building — the development also features double-glazed timber doors and windows to retain heat in winter and reject heat in summer. The thermal mass “heat bank” in living-room floors and dividing “party” walls helps retain heat from winter sunshine for passive heating, and soaks up heat in summer to provide passive cooling. “Clerestory openings allow low-angle winter sun to penetrate deep into the interior and allow hot air to escape in summer evenings, while operable louvres allow winter sun to penetrate living areas, and shading to glass and outdoor recreational areas,” says James.

The Eliza apartments
Featuring a unique “parametric” façade that varies on each level, The eliza luxury apartments currently under construction within Sydney’s CBD have been designed by Tony Owen Partners to respond to changing solar, view and planning conditions. Comprising 19 two- tofour- bedroom units — including a three-storey penthouse — with panoramic views over parks and harbour, developer Ceerose expects eliza to be completed by 2012. One of several Tony Owen Partners projects using digital design techniques to create exciting environmental solutions, eliza’s interiors are inspired by the classics of 20th century design, while the fluid profile of the exterior will be combined with classic, elegant materials to produce a progressively designed yet stately building.

Adaptable designs
Having successfully embedded passive solutions — such as site optimisation, high passive solar/ thermal mass, correct ventilation, shading and insulation — into the design process, the next challenge, says Jade Vidal of Bower Architecture, is designing sufficiently flexible living areas. He says the key to maximising efficiency while minimising wastage — both in construction and power consumption — is designing homes with interconnecting zones that can transform along with the changing lifestyle of its occupants. “Sustainability is all about durability, not only functionally but also in terms of its attractiveness to future owners,” says Jade. “So the more adaptable the design, the more it will appeal to the next generation of buyers.” Jade and colleagues brought this rationale to bear when designing a new 400sqm residence in Caulfield in south-east Melbourne. Based on the client’s brief, Jade was charged with knocking down the long-standing family home and re-building a significantly bigger five-bedroom dwelling designed primarily for accommodating and entertaining guests. “We had to design a home that was flexible enough to be opened up or closed down when only the husband and wife are living in it,” says Jade. “While the downstairs area is the domain of the residing couple, the upstairs has been zoned the grandchildren’s space.” The central courtyard and a void running the length of the house connect these zones and allow natural light to be captured, absorbed and bounced throughout the house. But to achieve this outcome, the design had to overcome limited natural light to the site due to the neighbouring house to the north. By creating a void in an upper-height gallery with glass and louvres, light hits the facing wall and is reflected back into key living areas. On sunny winter days, heat stored in the walls is released through the house at night. By opening external doors and the louvres within the upper-height gallery, the house is able to “self-exhaust” during the summer. “The use of black zinc and charcoal block externally contrasts with and conceals a surprising interior flooded with natural light,” comments Jade.

Brisbane ecohouse
A central courtyard also features prominently in the recently completed Riddel Architecturedesigned Hill End, a six-star energy-rated ecohouse in Brisbane’s inner-city West End. Built on a narrow (10-metre-wide) lot running northsouth along the Brisbane River, 80 per cent of the materials used on the Hill End house were painstakingly dismantled from the dilapidated family home that previously occupied the site. Most of the timber framing, flooring, linings and claddings were able to be reused, with most of the remaining 20 per cent being sourced predominantly from recycled materials locally. To overcome site orientation challenges, the home was split over three levels to create a series of private spaces and openings along its north-south axis from front to back, thereby increasing the flow of warm winter sun and cooling summer breezes. Also guiding the arrangement of spaces within the Hill End ecohouse, says Riddel Architecure’s Simon Boundy, was the owner’s desire for adaptable living/sleeping zones. “They needed to be able to operate separately or as one to accommodate several generations of family while maintaining privacy, a business/ home mix or a nuclear family,” he adds. By combining large overhangs, window hoods, outdoor living spaces, blinds, solar control-low-E glass, lightweight building materials and generous ceiling heights — together with recycled polyester bulk insulation to roof and wall cavities with sisalation or reflective bubble-wrap — the house operates effectively without air-conditioning. A dropdown louvre to the river terrace also provides shaded summer morning outdoor living and prevents indoor spaces from overheating, while a trellis with deciduous creepers shades the north-facing balcony. While natural daylight is maximised through the building and window design to reduce the need for artificial lighting, the house is also selfsufficient in both power and water. Equipped with solar hot water and 3kW of high-efficiency photovoltaic panels on the north-facing roof, the house generates more than its daily requirements, with surplus power being put back into the grid. To fulfill the owner’s quest for complete autonomy (from utilities), the house also boasts 71,000 litres of rainwater storage. Through a system of cubes of 100 percent recycled polypropylene with permeable top, water enters a 26,000-litre courtyard storage facility and supplies garden irrigation and swimming pool top-up. Meantime, in the front yard there are two 22,500-litre concrete rainwater tanks below the driveway that supply all taps, hot water system, washing machine, dishwasher and toilet backup. “Creating a home that responds so well to the surrounding climate couldn’t have been achieved if designers, builders (Robert Peagram Builders) and owner weren’t 100 percent committed to the project and its stated outcomes,” says Boundy.

Maximising comfort
Not unlike the Hill End ecohouse, Miniter says the 2000sqm home he designed for a retired couple near Broke in the Hunter Valley wine country is further proof there’s no excuse for poor site orientation — regardless of the challenges the typography throws up. He says going out to a vacant lot with a compass and checking where the sun is at various times of the day is the most basic, yet most commonly overlooked step to maximising passive solar and thermal mass within the overall design. To provide the owners with a view of their vineyard and distant mountain range — over al fresco evening drinks — meant Miniter had to construct the external loggia that was south-west-facing. One of the truly outstanding features of this country entertainer, an eightmetre- wide loggia has been designed with ceiling fans to further enhance air flow while the use of drop lines keeps insects at bay and prevents hot summer sun reaching the living quarters of the house. Based on international resort-style accommodation, three-metre-high ceilings maximise convective air flow, while each of the six bedrooms within the home is equipped with its own private quarters and ensuite. Given that it was designed specifically to accommodate up to 12 guests, Miniter says the true measure of the home’s sustainability is the overall comfort factor of all occupants when there’s a full house — and without expensive air conditioning. While the owners decided not to opt for a PV solar solution, Miniter says with solar hot water and six-inch quad guttering supplying two massive 120,000-litre water tanks, the home is well on its way to being fully autonomous.

Publish at: , last modify at: 30/06/2013

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