Toodyay House - a solar passive success

While many people have success retro-fitting their homes with energy saving features, there is still no better way to create an energy efficient house than starting with the right block and the right design.

A recently completed home in Toodyay is one outstanding example of what can be achieved when a dwelling's impact on the environment is a forethought rather than an afterthought. Before you start to build get to know your block. Spend time on your block finding out wind directions etc before deciding where to put the house.

Key Design Features

Home owner Dr Monica Leggett, one-time lecturer on sustainable energy and a major contributor to the development of the education program associated with the Subiaco Sustainable Demonstration Home, decided to practise what she preached when it came to building her new house.

"I strongly believe that it's the individual's responsibility to be more environmentally aware and it makes psychological, environmental, social and financial sense to build a more sustainable house," Dr Leggett said. Good access throughout the home was yet another item the owner wanted addressed as this was to be the dwelling in which she would live during her retirement years. As such, it is a 'universal-access home', designed for wheelchair access and ease of living. Doorways are extra wide and the home is all one level with no steps.

The two bedroom, two bathroom single storey home was designed by Griff Morris from Solar Dwellings who came up with a number of clever ways to meet his client's brief. And, as Toodyay is known for being hotter than Perth in summer and colder in winter, a design that did away with the need for artificial heating and cooling was high on the list of requirements.

But, of course, the first and foremost consideration in designing any passive solar home is orientation. In this case, the block faces north-east but the house has been placed at an angle so that it faces 12 degrees east of north as well as being part way up the block so that it could get advantage from the breeze. The house takes advantage of the winter sun with all living and sleeping areas - as well as both bathrooms - facing north.

Like all good passive solar homes, the layout of the interior is only two rooms deep as this allows the best penetration of light and warmth through the home.

The northern orientation of the bathrooms not only provided warmth and light to these traditionally cold, damp spaces, it also helped to make the home a low allergen dwelling as natural light, good ventilation and warmth discourage the growth of mould and mildew.

Monica asked for the garage to be at the back of the house so that it did not interfere with the ability to better manage the solar access. The angle of the garage improves air flow around the building and allows the resulting shape of the house to pick up the breeze (from any direction) and push it through the home.

Windows were kept to a minimum on the east and west ends of the house to mimimise the penetration of the hot summer sun. However as the cooling breezes on hot summer days are the late evening and early morning easterlies, two small louvre windows have been included in the east side to let the breeze in with a minimum of window size. They are working really well.

It is no use designing a house for Toodyay, Northam or York with careful attention to a sea breeze that does not arrive on hot summer days.

Management Tools

The open plan kitchen and living area is the largest open plan space in the house and tiling through the house adds to this thermal mass which is slow to warm in the summer as well as holding the heat in winter with the lower winter sun.

A little extra cost on the glazing gave a better overall performance of the home while also giving a higher degree of security. The windows are made from laminated glass with a clear protective film on the inside, enabling them to reduce heat transfer without a reduction in light penetration. Louvre windows have also been fitted at strategic points to allow cross flow ventilation.

The specially treated windows, venetian blinds as well as curtains and eventually a pergola are some of the tools which help Monica control the temperature and comfort of her home naturally.

Although the main living area is open plan, all the other areas can be isolated. By shutting off these areas, Monica can keep the central area cooler.

Compromises were made with the width of eaves. They needed to be wide enough to provide shade in late summer and early autumn but narrow enough to allow light in during winter. To accommodate this Monica plans to have direct control over them by installing a pergola with motorized, angled slats over a section of the patio doors so that she can close them on rainy days and when the hot sun is unwanted, open them during times when she needs the light and warming rays. She also plans to complement this with appropriate planting of deciduous vines to provide shade in late summer but allow the sun into the house in spring.

To further enhance this home's passive solar performance, insulation was added to the east and west walls. There is insulation throughout all the ceilings as well as glass fibre insulation with a foil coating under the roof to further reduce heat loss in winter and heat gain in summer. This double application of insulation in the roof cavity - one sitting on top of the ceiling, the other directly under the roof sheets - will help the interior of the house to retain a comfortable living temperature.

Also on the roof is an Ecovent for releasing hot air from the roof cavity. This vent is thermostatically controlled so that it opens only when there is excessive heat in the roof space.

With ceiling fans in the bedrooms and living areas, energy efficient lighting, a waterwise garden and three rainwater tanks, there is no doubt that this home is a showcase of great energy saving ideas. Even on the hottest of days, the temperature inside the home is more comfortable than Monica's previous Toodyay house which was air-conditioned but had the wrong orientation.

"How you 'manage' your house is one of the keys in reducing home energy consumption," she explains.

"I have an indoor/outdoor thermometer so I can monitor the temperature variations. On hot days, I don't open up my house until it is cooler outside than it is inside. I also try to reduce my use of appliances as well as the number of appliances I own. This reduces both embodied energy and energy consumption."

If you want to find out more about good passive solar design go to our home design pages. You can also call the Energy Smart Line on 1300 658 158 for a range of brochures on how to reduce your home's energy consumption.