New Cottesloe home designed to impress using minimal energy

For an environmentally conscious architect like Garry Baverstock, the decision to build a new home for his family was an ideal opportunity to prove, yet again, that there's no need to sacrifice aesthetics when creating an energy-efficient home.

Aptly named the Eco-Compound, this recently completed home in the suburb of Cottesloe, looks just as impressive as many of the surrounding residences. But, don't be fooled - this is far from being your run-of-the-mill luxury home. In fact, this home actually has very little in common with others in the neighbourhood as it has none of the excesses that usually accompany a palatial abode. There are no water-guzzling lawns, no inappropriate, non-water tolerant garden plants, no energy-draining chandeliers, no giant air-conditioning units and no large expanses of unshaded glazing. This is an eco-friendly house and one that stays cool in summer and warm in winter, yet using hardly any energy to do so.

Structural considerations

"Building an energy-efficient home starts with having the right block," explains Garry.

"This home has been orientated and shaped to take full advantage of the northern sun in winter. We have also placed windows in the right areas to allow us to capture the winter sun and use it as a source of free heating and free illumination inside the home."

As artificial heating and cooling is the biggest consumer of energy in the average home, eliminating the Eco-Compound's dependence on non-natural climate control was a major priority. While the building's orientation was one way in which this was done, the use of heavyweight materials was another. So, to ensure good thermal mass, the internal walls are constructed from brick (with a render finish) and externally, thick rammed limestone was used.

Ventilation windows were also strategically placed to collect cooling breezes at night during summer, and all the main rooms have ceiling fans to help circulate air and to drop the perceived temperature by around four degrees.

So successful have these solar passive initiatives been that the temperature in this home has yet to go below 22 degrees at night, even when it has been as low as 11 degrees outside. The success also applies to hot days.

"The day we moved in during March it was 39 degrees and the following day the temperature hit 42 but inside the house it was extremely comfortable,' says Garry. "At night we just opened the windows and turned on the ceiling fans."

Garry adds that a good solar passive home should have a maximum temperature increase of five degrees on a very hot day and two degrees on a normal warm day. And, in winter, this home should be 5-10 degrees warmer than a non-solar passive dwelling - amazing results using minimal electricity.

But this home is as much an energy-efficient home as it is a solar passive one - meaning that all areas of energy consumption were considered; not just heating and cooling.

Appliances and fittings

The sun's heating properties were utilised through the installation of a solar hot water system. A gas booster was added to provide hot water on cloudy days and the system operates to reduce water consumption as well using a dual-tank setup so that there is minimal to no cold water coming through the hot tap when the tap is first turned on.

Further water savings are made through the incorporation of a rainwater tank and the recycling of grey water from the laundry. The grey water is used to trickle irrigate the low water use native plants and fruit trees and there is an additional discharge tank underground to provide slow water seepage to the surrounding soil.

When it came to kitchen appliances, energy ratings were a major consideration in making the selection and the hot plates are an induction variety which run on electro-magnetic radiation.

Lighting

Due to careful design and planning, only minimal light fittings were needed inside the Eco-Compound. The need for artificial lighting was greatly reduced by the incorporation of skylights in the core of the home; these skylights comprise slats that are angled and spaced to allow winter sun in but exclude the hot summer sun.

"The skylights provide a central source of light that filters through the house and there is definitely no need for artificial lighting during the day," Garry says.

After dark, illumination is provided by low energy lights (many with dimmers) and fluorescent tubes - all strategically placed for maximum effect.

Electricity generation

To further reduce the home's reliance on electricity from the main power grid, a series of photovoltaic solar panels were added to the roof. It is anticipated that these panels will generate more than enough electricity to cater for the dwelling's use. Any excess power will be returned to the main power grid.

There is no denying that this home destroys the myth that an energy-efficient house can't be aesthetically stunning in its design and style. It's a home that is big on visual appeal and low on energy use and one that is sure to make people think twice about their priorities when building a new luxury home.

"These days status is the number one driver in house design and we need to make non-energy efficient homes a negative status symbol."
Garry Baverstock, Ecotect-Architects, Perth.