Glanville, South Australia

New house using passive solar design, including a combination of heavy and lightweight materials, to overcome the constraints of a narrow block where the longest side faces west.

The house as viewed from the street. A roof of the carport has solar panels which are east-facing.

The home has a 6.2 kilowatt (kW) photovoltaic system with east-facing panels forming the roof of the carport and west facing panels mounted on the main house roof.

Photo: Finn Howard (© Finn Howard Photography)

NatHERS thermal comfort rating

8.1 Stars

Heating: 26.2MJ/m²/year

Cooling: 16.6MJ/m²/year

Total: 42.8MJ/m²/year

Sustainability features

  • Reverse brick veneer and lightweight cladding
  • Tightly sealed building envelope
  • Double-glazed, thermally broken windows and doors
  • Heat pump hot water system
  • Solar photovoltaic (PV) panels
  • LED lighting
  • Ceiling fans
  • Rainwater tanks for internal use
  • Reducing stormwater runoff
  • No volatile organic compound (VOC) paints and finishes

Project details

Building type: Low density housing

NCC climate zone: 5 – warm temperate

Designer: Matt McCallum (Living Building Solutions), Ashlee Goodchild

Builder: Owner builder

Size: 145m²

Size of land: 375m²

Cost: $240,000

Site, block orientation, location and climate

This 375m² corner block is located in the north-western suburbs of Adelaide, in a warm temperate climate zone with hot, dry summers and cold, wet winters.

The block has a challenging orientation for passive solar design, with the street on the northern elevation and the block’s longest open side facing west.

A view from the outdoor courtyard towards the house with a timber deck and large sliding glass doors.

The second pavilion is separated from the bedroom wing by an internal study and external courtyard. High windows bring northern light into the rear of the home.

Photo: Finn Howard (© Finn Howard Photography)

Design brief

The owners wanted to demonstrate that it was possible to cost-effectively build a comfortable and efficient new home, while overcoming the poor orientation of this suburban block.

The owners had already built a high performing house on an ideally orientated block. Their previous home was optimised for winter conditions, but on this project they wanted to achieve greater indoor comfort during Adelaide’s hot summers. Heatwave events are predicted to become more frequent and severe in the future, and rainfall is expected to decrease over time. The owners wanted to focus on passive cooling because their last home became too warm in summer. The designers were aware that prioritising this goal may result in a cooler house in winter, so they sought an efficient heating solution for use on days with little or no sun.

Design response

The house plan was kept deliberately small, with just 2 bedrooms, 2 bathrooms, a study and main living area. Anything larger would be more expensive to heat and cool, resulting in higher energy bills. Keeping the plan as small as possible would also save materials in construction.

The house is divided into 2 distinct sections to overcome the challenges posed by the site’s poor orientation. The front part, which overlooks the street and faces north, resembles a single-fronted cottage. It blends in with the traditional cottages in the neighbourhood with a veranda and narrow eaves, 30° pitched roof and lightweight construction.

Room placement has been carefully considered in the design, with lesser-used spaces such as the laundry, a bathroom and storage placed along the western orientation where the sun can typically make rooms heat up in the afternoon. There are very few windows on this side of the house to limit heat gain.

The bedrooms are on the eastern side of the front section of the home, so that they will not be affected by the sun in the late afternoon and become uncomfortable for sleeping. The east-facing carport continues the roof line of the bedroom wing.

A second pavilion towards the back of the block is separated from the bedroom wing by an internal study and external courtyard. This allows the main living space to capitalise on a more favourable northern outlook. The open plan living room, featuring kitchen, dining and lounge spaces, benefit from high-level windows that facilitate cross ventilation using the local sea breeze. The carefully positioned doors and high-level windows also bring in abundant natural light.

Considerable attention was paid to outdoor areas across the site to help counter the challenging orientation. Deciduous plants in the courtyard provide summer shade and the western edge features bamboo planting that mitigates heat build-up inside. Existing trees outside the western boundary also help in this regard.

A view from the street shows a fence that is made of metal sheets that have been cut decoratively to produce a pattern.

The front part of the house is a lightweight construction designed to blend in with the single-fronted cottages of the neighbourhood, with a second pavilion towards the rear designed to capitalise on a favourable northern outlook.

Photo: Finn Howard (© Finn Howard Photography)

Cladding

This house is constructed using a combination of heavy thermal mass and lightweight cladding. East and west walls are constructed using concrete limestone blocks made from reconstituted lime and cement. These were chosen for their ability to store warmth and coolth and provide stable indoor temperatures, especially in summer. The remaining walls and roof were made from lightweight cladding to limit embodied energy where possible.

The east and west walls are constructed using reverse brick veneer, comprising of framed timber studwork to internals, internal limestone blocks and external walls made from structural insulated panels (SIPs), steel wall cladding and matrix boards.

The roof is made from lightweight steel, apart from the carport, where solar panels form the roofing material.

Windows and doors

All of the windows and sliding doors are double glazed with thermal breaks to help stabilise the internal temperature across the extremes of summer and winter.

The front door and laundry door have security mesh screen doors added, which makes them easier to leave open at night to flush out hot air in summer.

Heating and cooling

This house has been designed to remain cool inside as Adelaide experiences more extreme summer temperatures, with heatwave conditions and maximum temperatures projected to increase over time.

The house uses passive design techniques such as:

  • extended eaves that protect the high-level northern windows in the living room
  • the placement of windows and doors to capture breeze paths through the main living and passageways
  • shading to windows and walls in summer to reduce heat transfer from the outside.

In certain places throughout the house, thermal mass such as concrete floors and reverse brick veneer walls absorb heat from the sun to help naturally warm the home in winter.

The owners also installed a slow combustion wood heater for winter warmth. It is mainly used on cloudy and rainy days, because the house passively captures and retains heat from the sun on sunny winter days.

There are ceiling fans in the bedrooms and main living area, but no air-conditioning in the house.

Insulation and sealing

The house is well insulated with a reflective blanket in the roof (R1.5), earth wool in the ceiling (R6), and earth wool to the internal walls (R2.5). Structural insulated panels (SIPs) were used for the external walls to provide structural integrity and insulation in one product with very little waste.

A protective membrane between the internal and external walls helps to reduce moisture transfer from outside to inside and the build-up of condensation in the walls.

The house was subjected to a blower door test to establish the airtightness of the design and construction. It achieved a result of 4.7 air changes per hour (ACH), indicating that it is tightly sealed against leaks. This helps to reduce heating and cooling costs.

The house was subjected to a blower door test to establish the airtightness of the design and construction. It achieved a result of 4.7 Air Changes Per Hour (ACH), indicating that it is tightly sealed against leaks reducing heating and cooling costs. The average result for new Australian homes using the blower door test was 15.4 ACH, according to a CSIRO Study.

A study area with a desk and rug on the floor.

The study area links the front and rear pavilions. All of the windows and sliding doors are double glazed to help stabilised the internal temperatures across the extremes of summer and winter.

Photo: Finn Howard (© Finn Howard Photography)

Lighting

Rooms are naturally lit during daylight hours with many high windows on the north and the east. An external courtyard on the north also brings natural light into the home.

To reduce the energy consumption of after-hours electric lighting, LED light fittings were installed throughout the house.

Appliances

The home uses all electric appliances, including an induction cooktop and a heat pump for hot water, and appliances are largely fuelled by solar power generated on the roof. There is no gas connection to the home.

Renewable energy

The home has a 6.2kW photovoltaic system with a 5.0kW inverter, with east-facing panels forming the roof of the carport and west-facing panels mounted on the main house roof.

Since it was installed in April 2018, the solar electricity system has supplied approximately 3 times the energy needed by the household.

The owners opted for an oversized system to provide sufficient energy for future battery storage, especially over cloudy days in winter. The owners plan to install batteries and disconnect from the grid to become self-sufficient for energy in future.

Hot water

The house has a 320L heat pump for hot water. This was chosen because heat pump technologies work well in this climate, and the storage capacity means the owners will never run out of hot water. The system is also very quiet in operation and will require little or no maintenance over its projected lifespan.

Water

Expecting Adelaide’s rainfall to decrease over time, the owners installed 2 x 3,500L rainwater tanks. These are located on the western wall outside the living room, where they provide a buffer against heat absorption, and are plumbed to the internal cold-water taps. All of the downpipes from the main house flow into these 2 tanks, thereby maximising water capture.

Measures have been installed throughout the home to ensure the water is suitable for drinking. These include leaf guards on the gutters and rainwater flush diverters on down pipes, which divert the first rainfall to exclude any dirt that has settled on the roof since the last rain. There is also a water filter on the kitchen sink tap.

Inside the home, all of the taps, showers and toilets are WELS-rated to 5 stars, to reduce water consumption.

Outside, the owners planted a mix of succulents and natives in the garden to reduce the need for manual watering. They also chose porous landscaping materials to reduce stormwater runoff.

The glass sliding doors in the living room open to the outside courtyard.There is a brick wall that provides a high thermal mass.

The study area links the front and rear pavilions. All of the windows and sliding doors are double glazed to help stabilised the internal temperatures across the extremes of summer and winter.

Photo: Finn Howard (© Finn Howard Photography)

Waste

The selection of building materials, including structural insulated panels (SIPs), limestone blocks and lightweight cladding, which integrate structure and cladding, meant there was minimal construction waste removed from the site during the build.

Embodied energy

The house features some materials like concrete and reverse brick veneer that were selected for their thermal mass to passively heat and cool the home, but are high in embodied energy from their manufacture. However, lightweight materials, such as structural insulated panels, steel cladding and roofing, and matrix board were used elsewhere in the home for their low embodied energy.

In addition, the landscaping uses a combination of bark chips and stone chips, which contain less embodied energy than concrete or paver solutions, with the added benefit of improving water retention on site.

Additional information

The owners selected a range of low waste and no-VOC finishes and fittings, including natural floor sealer and natural paints, natural coir carpet to the bedrooms, and recycled benchtops for the laundry and ensuite.

The owners have installed a vegetable patch to grow their own food, and plan to add beekeeping to their garden soon.

A graphical representation of the floor plan of a home.

Floor plan of Glanville house design.

Plans: Matt McCallum (© Living Building Solutions)

Evaluation

Because this house was conceived as an experiment to determine whether it was possible to comfortably and efficiently overcome the site’s limitations, the owner has installed thermal monitoring systems to compare actual energy consumption figures against design-phase predictions. The system takes hourly temperatures in 3 main rooms, providing data to help refine the building’s performance and to inform future builds.

This house maintains a comfortable internal temperature of around 21°C in winter. The lowest recorded temperature was 17°C at 5am one winter morning, when it was 5°C outside, and no heating had been used the previous night.

The sunlight we get into the building in winter is absorbed by the thermal mass, and because this is a well-insulated and very airtight building, once that heat is inside, it doesn’t get lost,’ one of the owners explains. ‘The reverse applies in summer. Also, being located on a corner block, the prevailing wind from the south-west comes into the house to cool it down after dark. Night purging is definitely the best way to control summer heat.

The owner says that easy and inexpensive methods such as installing adjustable shading, planting more trees, installing additional doors to separate zones and using an outdoor umbrella to shade windows in summer, have helped to cool the home.

The owner is waiting for a deciduous vine to fully grow before evaluating the home’s summer performance; however, he says that the building has met one of his main goals of being cooler than his previous home. ‘The block lends itself better to catching coastal breezes. We don't have air-conditioning and only used the bedroom fans a few times last year, usually when it's been 40 plus degrees that day and overnight lows are in the mid to high 20s.’

Author

Renew, 2020

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