This Mid North Coast couple spent $60 on electricity in three months

Mid North Coast couple Emma and Scott Kark have lived in their new passive home for a little over a year. Their electricity bill for the last quarter was $60. 

With their solar system hooked up in November, this figure is expected to drop.

💡What happened: When the Karks bought one hectare in Verges Creek, Kempsey Shire, they knew they were going to design and build a home using passive house principles. 

Why? Because they wanted to live sustainably – both environmentally and financially – and comfortably.

❓What’s a passive house: A passive house is a design standard that optimises the “thermal envelope” (the layer separating inside from outside) of a building. 

Such a house requires minimal heating and cooling by using insulation, airtightness, appropriate window and door design, and ventilation systems with heat recovery – a system that draws in fresh external air and extracts heat from outgoing, humid air for temperature control.

The design ultimately uses less electricity, saving money for the homeowner, while reducing their carbon footprint.

🌏 Designing for the current climate: With a warming planet and rising utility bills, passive homes make sense. 

The Karks hired an architect who specialises in passive house design.

Their single-storey, two-bedroom house is not only well-insulated, it’s vacuum sealed, eliminating any drafts. The airtight building has a vapour barrier wrap under the external cladding that prevents external moisture like rain entering, while allowing internal water vapour to exit to avoid damp and condensation. 

The home has double glazed windows, and a heat recovery ventilation system. It’s north-facing and the floors are made of concrete to utilise sunlight to warm the home. Scott built a pergola on the west-side of the house and curtains are used in their west-facing bedroom during the warmer months to keep the house cool.

💰 The bottom line: The build cost the couple about $460K, not including the architect fee. 

Emma said it “cost a bit more than building a normal house” but that some of the elements - recycled timber cladding, burnished concrete floors and large windows and sliding doors - were personal choices and not integral to the passive principles.

Regardless, the couple say the extra upfront outlay is already being paid off.

• “We definitely didn’t need the heater in winter. So we saved there,” Emma Kark told the Mid North Coaster. “I absolutely hate winter, and I hate being cold, but this was my favourite winter ever, because I barely even noticed it.” 

This summer temperatures in Kempsey Shire have peaked in the low 40Cs.

• “It has been quite hot,” Emma said. “We do sometimes put the aircon on, but only for an hour and it'll cool down the whole house. So it is really efficient at circulating air throughout the house.” 

⏩ Future of housing: Emma says passive design “should be the future of the housebuilding industry, from not only a sustainability point of view, but just a comfort point of view because it does make such a difference”.

🦺 Home Energy Assessor: Coffs Harbour’s Christopher Oakes is a carpenter. Born in Ireland, he has worked on passive houses in his home country, and believes they are important for our future.

Since moving to Australia he has become an accredited Home Energy Assessor, helping homeowners make changes and plan ahead to improve the energy efficiency of their existing homes while reducing their carbon footprint.

• “This is an area where Australia is really lagging behind,” Oakes told The Mid North Coaster.

He says Australians need to bring houses “up to standard if we want any chance of hitting our carbon reduction targets of net zero for 2050”.

🌡️ Rising temperatures: Australia’s National Climate Risk Assessment shows in detail how climate change is impacting our communities, economy, infrastructure, environment, health and way of life. 

The assessment also shows the difference between a rise of 2C in pre-industrial temperatures and a rise of 3C. As an example, there are currently about four severe/extreme heat days per year nationally, but under a 3C warming scenario this would climb to 14 days.

🏡 For all homes: New builds and existing homes can benefit from the passive house concept. You can learn online or consider hiring a home energy assessor to visit a home, measure the performance of the dwelling and the running costs, and present a plan on how the residents can make it better.

Oakes recommends changing lightbulbs to LEDs, and says the biggest contributor to home energy bills are hot water and swimming pools. 

• “Nothing else out there pays back as good as investing in things like solar, or a heat pump,” Oakes said. “Give it five or 10 years and you’re making money.”

A home energy assessor can cost between $300 and $500, sometimes more depending on the job.