Light house-designed house

Sustainable scientist

As Jenny Edwards moved from science communication to science in sustainable home building she gained an architecture business along the way.


Cass Proudfoot

Jenny Edwards is the director of Light House Architecture and Science in Canberra. This HIA member business is all about using mainstream builders and materials to build sustainable houses. They achieve impressive energy-efficient results by using clever science and smart architectural design. Even better, the use of standard construction techniques makes Light House homes affordable.

‘We don’t chase the newest technology, until it is proven, and readily available,’ Jenny says. But as the resident scientist, she keeps a close eye on new products and construction methods for energy-efficient homes.

The demand for sustainable housing continues to grow, as more people become aware of the comforts and energy savings of homes that need minimal heating and cooling. Light House homes are warm and light, even in Canberra’s cold winters, and it is all down to good design, and careful construction.

Builders don’t need specialist skills to construct Light House homes, just an interest in sustainable building, and pride in their work.

‘It is all about precision work,’ Jenny says. ‘They need to focus on sealing holes in the internal building envelope. But it isn’t rocket science.

‘We use standard construction except we use carefully taped vapour permeable membrane on the outside of the timber frame, instead of foil sarking.

‘Through good design we minimise the number of holes in the building envelope’

‘Through good design we minimise the number of holes in the building envelope. For example, by combining lights and ceiling fans or using wall mounted LED strip lighting rather than having lots of downlights, and not putting holes in the ceiling for ducted heating and cooling systems.

‘We also use good quality double glazing and ensure it is installed well. With good solar passive design there is often very little benefit in the extra expense of triple glazing in Canberra’s climate.’

Light House-designed houses are all about smaller, smarter design. They use thermal performance modelling software to check and optimise the energy efficiency rating of their projects at every stage of the design process.

‘Our homes are well oriented, and designed to be space efficient, well insulated and air tight,’ Jenny says.

For Light House, the inner gyprock lining is the vital part of the sealed building envelope. Even for renovations they often re-do the gyprock throughout the home to prevent air leakage.

‘In Canberra a well oriented, well designed home with an insulated slab, double glazing and wall and roof insulation will only need heating in the very coldest months, and won’t need any air conditioning at all,’ Jenny explains.

This is an impressive result for a city with summer temperatures up to 40 degrees, and winter lows down to minus six or even lower.

Jenny Edwards
Jenny Edwards, director of Light House Architecture and Science
Photo courtesy Living Green Designer Homes
Light house-designed house 2
The use of standard construction techniques makes Light House homes affordable
Photo courtesy Living Green Designer Homes

With such a variable climate, it is worth the extra care taken in the construction process, to end up with homes that stay comfortable no matter the weather extremes outside.

Light House has a full testing regime for their builds, using a blower door to test for air leakage in the building envelope and a thermal camera to find the cold spots or gaps in the insulation.

‘Builders can be terrified the first time I come in with the blower door and camera to test the building performance,’ says Jenny. ‘But once they realise it is just about sealing up any gaps they understand.’

Jenny herself has been the victim of badly designed and built homes ‘with frost forming on the inside of the bedroom windows at night’. Those cold nights are part of what drove her to create something more suitable for the climate.

It all started with a Canberra home she bought in 2007. ‘It had good orientation, and an EER of 2.5, but lacked insulation, and had very leaky single glazed windows,’ she remembers.

So there was room for improvement, especially in draught reduction. Around this time Jenny saw a blower door in action on TV.

‘So I thought, ah, that is what I need for my house, I’ll ring up and organise a test.’

‘Our homes are well oriented, and designed to be space efficient, well insulated and air tight’

But it wasn’t that simple. The one she’d seen on TV was in Victoria and turned out to be the only one being used for residential testing in Australia. Also around that time she discovered thermal cameras.

‘I realised there is a perfect match, team up the blower door testing with the thermal camera and you can actually communicate the results to people with something they can see.’

The blower door tests the overall air leakage of the house, while the thermal images can show hot or cold spots where air leaks create temperature differences.

Not one to wait around, Jenny took her idea and ran with it. She left her job, went to New Zealand to buy a blower door, trained in large-scale air leakage testing at the Wisconsin Energy Institute in the US, learned all about thermal performance modelling in Australia and then started up a business in Canberra doing house energy efficiency rating and performance testing.

Demand was high and she soon found herself working with an architecture and building company, then joined them full time as a director and energy adviser.

As demand for energy-efficient houses expanded, the design part of that business grew too big for the construction side to handle. The business separated, and the design and energy side was reborn as Light House Architecture and Science, with Jenny as the sole director.

Light House
Our homes are well oriented, and designed to be space efficient, well insulated and air tight
Photo courtesy Living Green Designer Homes
Light House
Light House homes are warm and light, even in Canberra's cold winters
Photo courtesy Living Green Designer Homes

Not many architectural businesses have a scientist at the helm, but Jenny is making it work at Light House. In fact, she has always had a strong interest in architecture and building.

After high school, she seriously considered studying architecture, but eventually followed her friends to the local university and did science.

‘But it was a hard decision,’ she says.

Home design took a back seat to science for a few years as Jenny gained a masters in science communication, and worked in Canada, Western Australia and the Philippines.

‘And I lived in some dreadfully uncomfortable houses, and a couple of good ones in that time,’ she says. ‘So when I came back to Canberra I knew I wanted a really good house.’

Now she has made herself a really good one. In September Jenny’s own home won the HIA Australian GreenSmart Sustainable Home award.

The home was designed by Light House and built by 360 Building Solutions. ‘It really works,’ she says. ‘I have teenagers, but our energy use is that of a single person. And it is a wonderful, warm house to live in – I love it.’

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