Cape Paterson, Victoria

A house that aims to balance energy efficiency and material selection to achieve affordability and sustainability.

A photo of a new build in Cape Paterson. The north side of the house features a row of solar panels designed to shade the interior from high summer sun.

The house is designed to take advantage of sunlight and prevailing south-west and north-west winds. Solar panels are oriented to the north for power production and to shade the interior from high summer sun.

Photo: Warren Reed (© Beaumont Building Design)

NatHERS thermal comfort rating

9.1 Stars

Heating: 16.5MJ/m²/year

Cooling: 8.8MJ/m²/year

Total: 25.2MJ/m²/year

Sustainability features

  • Sealed airtight building
  • Recycled solid bricks for thermal mass
  • Insulated concrete slab with cement replacement and recycled aggregate
  • Electric clerestory windows
  • Argon-filled double-glazed low-emissivity (low-e) windows
  • Solar photovoltaic (PV) system with battery for energy storage
  • Heat pump hot water system
  • Energy-efficient appliances
  • LED lighting
  • Rainwater tanks
  • Water-efficient toilet suite and tapware
  • Low-formaldehyde joinery (E0 rating)
  • Low volatile organic compound (VOC) paint
  • Food production

Project details

Building type: Low density housing

NCC climate zone: 6 – mild temperate

Developer: The Cape

CORE 9 designer: Beaumont Building Design

CORE 9 builder: TS Constructions

Energy management: Phillip Island Energy Rating

Size: 167m² (house 131.59m², garage 35.59m²)

Size of land: 456m²

Cost: $420,000 including garage

Site, block orientation, location and climate

The house is located on the outskirts of Cape Paterson, a coastal village 144km south-east of Melbourne. The oceanic climate has south-west to north-west prevailing winds. The average daily maximum temperature is 13.5°C in winter and 23.5°C in summer.

The property is on a corner block of a residential development, The Cape, with a clear northern frontage to the street.

 

The angled blades of a shading device on the outside of the house.

Fixed shading on outdoor areas allow winter sun to enter through north-facing glazing, but excludes summer sun.

Photo: Warren Reed (© Beaumont Building Design)

Design brief

The developer requires that every house in the residential development:

  • has a NatHERS rating of at least 7.5 stars
  • is less than 200m² in size
  • has at least 2.5kW of rooftop solar
  • has a 10,000L rainwater tank
  • adheres to passive solar design principles.

The entire site is all-electric and has no reticulated gas.

The designer wanted to create an affordable, carbon-positive home that uses renewable energy sources to reduce running costs and generate enough energy for the home’s operational needs (with surplus fed back to the grid).

The house had to:

  • be suitable for a family, with 3 bedrooms, 2 bathrooms and open-plan living areas
  • be designed with passive solar principles for light, ventilation, heating and cooling
  • eliminate wasteful spaces to reduce construction costs, as well as heating and cooling loads.

Design response

CORE 9 is a low-maintenance, compact, 3-bedroom house. Starting with a rectangular shape, the designer tested the width, length and height ratios that would reduce costs and optimise energy efficiency.

The house is positioned and designed to take advantage of sunlight and prevailing south-west to north-west winds. The house faces north for daylight and low winter sun, and the inverted roof truss with electric clerestory windows increases light and passive solar gain. Solar panels face to the north for maximum energy production and shade the interior from high summer sun.

The layout uses open-plan living areas with no hallways or entrances. The living, sleeping, and wet areas are zoned to provide privacy, decrease noise disturbance, and assist with thermal control.

Building products, such as low-carbon concrete flooring and reverse recycled-brick veneer walls, reduce the environmental impact of construction and provide thermal mass. The construction uses recycled and upcycled materials that can be reprocessed after use, and standard material lengths that minimise off cuts.

The open-plan living area features clerestory windows, large sliding glass doors and a ceiling fan to help maintain comfortable temperatures, year round.

Operable clerestory window in the living areas purge hot air in the warmer months.

Photo: Warren Reed (© Beaumont Building Design)

Cladding

Lightweight steel is used for the external cladding and roofing because it is a durable, low-maintenance, high-strength product that has excellent spanning capability. The cladding is painted with a natural material that uses no artificial glues, resins or formaldehydes in its production.

Windows

The house features double-glazed windows inside thermally broken aluminium frames. These windows have a reinforced polyamide strip between the inside and outside aluminium profiles that create an insulated barrier within the window frame. The polyamide strip has low thermal conductivity to minimise heat transfer and improve thermal performance. For more information on insulated glazing units, refer to Glazing.

Heating and cooling

The house maintains a comfortable temperature range of 18°C to 25°C most of the year with no artificial heating and cooling. This is achieved through passive solar design and material selection.

The house is oriented north and has sliding glass doors, clerestory windows and a raked roof truss for passive solar gain in winter. There is a 900mm eave overhang and solar PV pergola that minimise solar absorption in summer, and a timber blade shading system that obstructs western sunlight.

Windows on the south, east and west façades permit cross ventilation and natural cooling. Openable clerestory windows in the living areas remove warm air, and eaves and blinds shade windows in summer.

The thermal mass of the concrete floor and reverse brick veneer walls help regulate internal temperatures. Ceiling fans and smaller windows on the south and east elevations increase air circulation and cross ventilation.

An exposed brick wall in the kitchen helps regulate internal temperatures.

The northern orientation and compact floor plan bring daylight into the kitchen. Recycled solid bricks provide thermal mass.

Photo: Warren Reed (© Beaumont Building Design)

Insulation and sealing

The house has underslab insulation, wall and ceiling batts, and a roof blanket. There is R2.5 glass batt insulation and a 20mm air gap in external walls, R5.0 glass batt insulation in all ceiling areas, a R1.0 roof blanket underneath the metal roof, and R1.5 underslab insulation. There is no insulation in the internal walls.

All windows are tightly sealed to minimise air leakage, and external frames are sealed to the floor to eliminate air movement beneath the frames.

A modern bedroom features an exposed brick wall and a ceiling fan. Natural light enters the bedroom through a north facing window.

This bedroom has a reverse brick veneer wall for thermal mass and ceiling fan for cooling where needed.

Photo: Warren Reed (© Beaumont Building Design)

Lighting

The northern orientation and compact floor plan of the house allow daylight into the kitchen, dining, lounge, and 1 bedroom. The north-facing floor plan extends out on the east and west so that all living areas and bedrooms receive sunlight. The inverted roof truss with high clerestory windows increases the levels of natural light to reduce the need for artificial lighting.

There are 16 sealed LED downlights throughout the house, saving energy costs and greenhouse gas emissions over the lifespan of the fitting.

Appliances

Appliances have been specified for their affordability and energy rating. Energy-efficient appliances include: an induction cooktop; a water- and energy-efficient dishwasher; a 4-star-rated fridge; a hot water heat pump; LED lighting; and water-saving taps, showers and toilets.

Renewable energy

A 6kW solar PV system with a 4.8kWh battery powers the home during the day and stores enough energy for much of the night. Any excess electricity from the system is returned to the grid.

There is a 15-amp electric car charging point in the garage that uses solar electricity.

An isolator switch ensures there is no wasted electricity while the house is not in use, cutting power to everything but the fridge, smoke detectors and sensor lights.

An open-plan living area features a recycled-brick wall, the remaining walls are painted white. The ceiling is made of a blonde panelled wood.

Reverse recycled-brick veneer walls and a concrete slab floor provide thermal mass.

Photo: Warren Reed (© Beaumont Building Design)

Hot water

A heat pump hot water system has a 4.5 COP (coefficient of performance). The hot water system generates 4.5kWh of hot water for every 1kWh of energy used and can be powered by the onsite solar PV system.

The bathroom, laundry and kitchen are close to each other so shorter pipes can be used. This minimises heat loss and increases the efficiency of material use.

Water

To reduce reliance on mains water, two 5000L rainwater tanks are connected to the toilets and all external taps. Water-efficient appliances and fixtures, such as the kitchen tap, shower heads, toilet, dishwasher and washing machine, also reduce indoor water consumption.

Native species have been planted in the garden to decrease outdoor water usage, and a lack of paving allows water to be retained on site by reducing run-off.

Waste

A goal of zero waste was set for the construction of this house.

The design uses prefabricated materials and standard sizes and lengths in common building materials to reduce offcuts. Exact quantities were ordered from suppliers to avoid unnecessary packaging of goods.

Materials that could be upcycled or had a recycled component were used where possible to reduce potential landfill. Recycled solid bricks were used in the walls, and fly-ash, a by-product of coal combustion, was added to the concrete slab. All waste produced during construction was sent to a transfer centre, where components were separated and recycled.

All waste from the site during construction was sent to a transfer centre where components were separated and recycled.

Recyling bins have been incorporated into the design to encourage householders to recycle.

An isolator switch ensures there is no wasted electricity while the house is not in use, shutting down power on exit to everything except the fridge, smoke detectors and sensor lights.

Embodied energy

Materials and construction processes that reduce embodied energy were selected. The building was designed for longevity, reducing its maintenance and embodied energy over time.

Locally sourced and Australian-made building products were used to reduce embodied energy generated during transport and delivery to the site. The timber framing, trusses and cladding are sustainable plantation timber and recycled timber, and the walls are recycled brick. The low-carbon polished concrete floor includes a 30% blend of cements that are more environmentally friendly, such as slag and fly ash, to lower the lifecycle impact of the product.

A graphical representation of the floor plan of a home.

The floor plan places living areas to the north for solar heat gain in winter, has zoned areas for heating and cooling and places bedrooms to the south where they may be cooler in summer.

Plans: Beaumont Building Design (© Beaumont Building Design)

Additional information

There are numerous shared facilities at The Cape to encourage residents to make more sustainable choices. The development is also planning to add a 7000m² community garden, along with a greenhouse, composting areas, worm farms, an orchard and poultry. This will give residents access to locally grown organic produce, decreasing their grocery expenses and providing the health and social benefits of gardening.

Evaluation

This house has won several national, state and regional awards, including 2019 HIA Australian GreenSmart Home and HIA Australian GreenSmart Sustainable Home.

The house is a prototype and has been used as a display home. Several energy bills have been received in credit. An assessment of the home’s energy consumption has predicted a credit of $200 per year for an average family of 4. This matches the stated goals to eliminate utility bills with a mix of solar power, solar hot water and rainwater harvesting.

Based on its performance as a display home, internal temperatures are likely to remain between 18°C and 25°C for most of the year.

Author

Renew, 2020.

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