Net zero evolution

Built with precision and restraint and the clear intention of demonstrating that sustainability and environmental principles can co-exist with volume building philosophies, SHINKA House represents a blueprint for the future of the Australian suburban family home.

The 300-square-metre, four-bedroom beauty was designed and built by development and residential building company Sekisui House. It’s located at Gledswood Hills, a planned community in Sydney’s south-western suburban growth corridor. Construction commenced in 2018, and after an extended showing, the home sold at a hotly contested auction in June last year.

So what makes SHINKA House so different from its neighbours? Aside from its contemporary aesthetic, it stands out because it’s one of the first 8-star net-zero energy homes to be built on a Sydney greenfield site. Behind the street frontage, this home offers unsurpassed comfort, liveability and high-level environmental credentials. ‘Net-zero energy’ means the house itself generates as much energy as it consumes – and it consumes very little.

With its focus on sustainable urban development, Sekisui House has been transforming the global housing landscape since it was established in Japan in 1960. The company arrived on Australian shores in 2009 and has master-planned about a dozen communities around the country – including West Village in Brisbane, which features a magnificent shared green space called ‘The Common’ that won the 2021 HIA Australian Outdoor Project award.

While SHINKA House is its first foray into net-zero energy in Australia, it’s something the company has been doing for a long time in other housing markets. ‘In Japan, almost 90 per cent of homes we build are net-zero energy, and we’ve built over 60,000 net-zero energy homes worldwide,’ says Craig D’Costa, executive general manager of Sekisui House Australia.

‘With SHINKA House, we targeted a NatHERS rating of 8 stars and achieved 8.1,’ Craig says. ‘However, we did that in the context of a price ceiling. We were conscious about trying to deliver a home that achieved a high level of sustainability and low-operating costs and still be attainable by the average consumer from a cost perspective.’

The home’s performance is underpinned, first and foremost, by a well-considered design. ‘We took the approach of looking at the passive design before adding or augmenting with appliances or other technology,’ Craig explains. ‘There’s a lot of work that can be done by paying attention to the orientation, having windows in the right locations, external shading elements and eave overhangs, and thermal mass in the right locations to ultimately reduce the operating costs of that home.’

The crafted interiors are gently evocative of Sekisui House's Japanese heritage, with architectural timber elements, uncluttered lines and a crisp monochrome palette. A centralised void soaring above the living areas and generous amounts of glazing create an overwhelming sense of space and light. This openness of the design, which characterises many Sekisui House homes, is a by-product of the company’s proprietary construction system, SHAWOOD. ‘It’s a different construction methodology to traditional building in Australia,’ Craig explains. ‘At the core of a SHAWOOD home is what we refer to as a metal joint glulam structural frame system. The laminated timber posts and beams, imported from Finland, are tested and rated for structural capacity. We use a portal framing technique that allows us to span post-to-post up to seven metres. Then we expose the beam, so it creates that distinctive architectural language.’

The structural components of the SHAWOOD system deliver millimetre-perfect calibration and are designed to lock together for extreme rigidity and strength. For SHINKA House, Craig says the construction tolerances onsite were around three to five millimetres. In terms of energy efficiency, this translates into superior air-tightness – an essential factor in optimising the home’s thermal stability. Together with high-performance double glazing and insulation, the operational electricity demand for heating and cooling in SHINKA House is predicted to be 85 per cent less than the average Australian home.

Technology plays a supporting role: essential but also secondary to the design and construction innovations. The house carries a traditional PV generation system coupled with a 7.2 kW/hour storage battery. Water and energy-saving appliances, LED lighting, geothermal augmented air-conditioning, and smart automation systems round out the package.

Fittingly, SHINKA translates to ‘evolution’. And that’s really what this amazing house represents. At every design and development stage, the focus was on delivering a home with broad consumer appeal, a home that’s attainable and replicable. Something that, in time, will effortlessly translate into the mass market.

‘Sekisui House has a stewardship of sustainability in all our products, whether it be land development, apartment projects or housing,’ Craig says. ‘We hope that in the future, when consumers are looking to build a new home, they are considering things like orientation and sustainability inclusions as essential criteria, along with things like the facade or interior cosmetic features.’

www.sekisuihouse.com.au 

Materials:

• Power charging for electric vehicles
• Roof & ceiling insulation exceeding R5.0; external wall insulation R2.5
• 3.48kW PV system
• 7.2 kW hr battery
• Water-efficient tapware, showerheads and appliances
• LED lighting with motion sensors
• Geothermal-augmented air-conditioning
• 3000-litre in-slab water tank
• SHAWOOD framing system
• Low VOC materials and finishes
• Double glazing