Katherine Post and Chris Gyngell had been looking to make a tree change for some time before stumbling across a beautiful bushland block with views over a manmade lake in Kyneton. 

Although at the time it was just scrub and a dusty car park, the then city-dwellers immediately knew this was where they wanted to build their family home. 

‘We wanted to build something really sustainably,’ says Katherine. ‘A family home where our kids could grow up comfortable and healthy, that settled gently into the landscape and trod lightly on the planet.’

Together with a sustainable dream-team including building designers Maxa Design, interior designers HeHe Design and builders Sanctum Homes, Katherine and Chris have created exactly what they set out to do. Their new home champions sustainable design and living, with passive heating so effective, it’s often a struggle in winter to convince the kids, Max (10), Heidi (7) and Pip (8 months), to dress for the outside temperature.

Here, they tell us how they did it! 

How long did the build take?

The build took seven months in total but the superstructure (using structural insulated panels known as SIPS) went up in just three days!

At what point did you decide you wanted to take a sustainable approach? Why?

After living in rentals for many years that were freezing in winter, hot in summer and had huge utilities bills we were pretty keen to build something that was as energy efficient as possible. 

The goal was to keep our impact on the environment as low as possible whilst also building a home that was really comfortable to live in. We asked our good friend Hamish White, director of Sanctum Homes, for advice and he recommended we look into PassivHaus – a building standard that originated in Germany and aims to build high performing homes that require minimal heating or cooling and are very energy efficient.

Can you please outline the sustainable elements of your new home?

It is built to the PassivHaus standard (currently awaiting certification from the Passivhaus Institut), which means it requires minimal heating and cooling to maintain a stable and comfortable temperature all year round, and is incredibly energy efficient. Our NatHERS rating is 8.2 stars. 

We have a heat recovery ventilation unit (HRV) which ensures a constant supply of fresh, filtered air indoors (the house is fully sealed so there are absolutely no draughts!) and removes stale air, moisture, and odours. We also have triple glazed windows and the house is carefully oriented for optimal solar gain. 

We are fully electric with solar panels and efficient appliances like a heat pump hot water system and an induction cooktop. Needless to say we were very pleasantly surprised by our first electricity bill, which was in credit!

Other sustainable elements of the build included; sustainable timber wall cladding; Colorbond wall sheeting, which has low embodied energy and a long lifespan; rainwater storage; heat pump heating and cooling – offset by the solar PV; and, high water efficient tapware throughout. 

Were there sustainable elements you wanted to include, but couldn’t? What were they and why?

We would have liked to include a battery to store the energy generated by our solar system but decided to wait to see how the technology evolves in the next few years – we will look definitely look at this in the future!

Were there sustainable elements you didn’t know about, and did end up including? What were they and why?

We didn’t know about heat pump hot water systems – these are brilliant and use very little energy to heat your water. We’ve been so impressed by our system and could never go back!

Did the inclusion of sustainable materials/elements impact the budget for the build at all? How?

It does cost a bit more up front to build this way – for example, high quality triple glazed windows are more expensive than standard windows. But there are big savings to be made long term with utility bills. We also wanted to ensure our building footprint was just the right size and not too big for our actual needs as a family, which is an important factor in the cost.

Another thing that helped keep our build on budget was to engage our builder early in the process to collaborate with our building designer. The builder was able to collaborate and advise on the design to ensure that our design was one that we could actually afford to build!

Some of the banks are now doing ‘green loans’ which means you qualify for a really competitive interest rate if you meet the criteria, so that has been a big saving for us as well.

What do you love most about this home now?

The house is so comfortable and easy to live in. We love waking up on a frosty morning in winter in a beautifully warm house that hasn’t had a heater on. It can be a bit of a challenge to get the kids to put a coat on before we head out the door because they don’t realise the temperature outside!

It’s also a beautiful part of the world that we feel so lucky to call home – in the last few weeks we have had an echidna knocking on our door and a beautiful family of Gang-gang cockatoos in our big tree, and we love watching the sun set over the lake.

Having now lived in the home for a while, how does it compare to living in a home without these sustainable features?

In the last rental we lived in before moving here, you could stand in the hallway in the middle of the house on a windy day and feel the wind blowing your hair. It just wasn’t sealed at all and full of draughts – it was really hard to maintain a comfortable temperature inside. And our energy bills were really expensive!  Living in a PassivHaus couldn’t be more different – it’s always a lovely comfortable temperature and the air quality in the house is really nice.

What has been an important lesson you’ve learnt during this process?

It’s so important to get a good team of people who know what they’re doing, share your values around sustainability, and who you trust to build your family home. It makes the whole process a pleasure and it shows in the finished result.

Any future plans for the house?

The house has been designed for us to age here (no stairs and plenty of good access!), so we’re hoping to spend many more happy years in this home.

This story was produced in partnership with Momentum Energy. Momentum Energy are owned by Australia’s largest renewable energy generator and offer accredited GreenPower. Sign up to one of Australia’s greenest power companies.