Residential Case Studies

Energy efficient household and work in progress

Karen in Torquay


Karen and her family are passionate about sustainability. Their home boasts two chooks, a garden full of home-grown produce, 11,100 litres water storage and an array of energy efficient features.

“We’ve set up our home to be as energy efficient as possible,” says Karen. “And it’s still a work in progress.”

Double glazed windows, wall and ceiling insulation, and individual climate control zones throughout the house enable the family to easily maintain a comfortable inside temperature all year round.

The installation of LED lighting cuts household lighting costs, turning entertainment equipment off at the switch – via a power board – saves on standby energy use, and swapping from gas boosted to electric heat pump solar water improves efficiency while reducing costs.

“We’ve set the pump to run between 10am and 10pm so it heats water during the day when the sun is out and while the system is working. Being well insulated, the system keeps water hot overnight, ready for our morning showers.”

The recent addition of a 5.9kW solar system with an estimated annual output of 8,246kW hours has boosted the family’s cost savings even further without compromising reliability.

Rather than the whole system linking to one large inverter, each panel has its own micro-inverter. This means if one panel gets shaded or dirty, it doesn’t affect system performance.

“Our installer provides ongoing monitoring, so having micro-inverters makes it easier to identify faults with individual panels. It also allows us to easily add more panels in future, if needed,” says Karen.

The family is now awaiting the arrival of a battery to store excess electricity and is planning to replace its gas cooktop with an electric one, ridding the household of gas altogether.

“Instead of $105, our first full month bill (after installing a 5.9kW solar system) showed a $2 credit.”

Solar panels and passive solar design a winning combination

Terrence in Aireys Inlet


Terrence and his wife have been Powered By Positive since 2008 when they built their new home. More than a decade later, their investment in a rooftop solar system and passive solar design is paying dividends.

It all started when Terrence spoke to several suppliers during a meeting organised by Surf Coast Shire Council at the Airey’s Inlet Hall.

“It just made sound financial sense – and it’s good for the environment,” says Terrence who has a commerce background.

The couple also investigated other ways of making their new home more energy efficient, picking up ideas during Surf Coast Shire’s Sustainable House Day. Seeing several passive solar houses in operation was an eye-opener and prompted the decision to incorporate passive solar design features into the new house.

These include north-facing windows to capture winter sun, external blinds against summer heat, double-glazing, draught-sealing and thermal mass to store heat.

“Our builder was unfamiliar with passive solar design principles and initially resistant. Now the company promotes itself as passive solar builders!”

By today’s standards, the couple’s 1.5kW rooftop solar system is small. Together with passive solar design however, their energy bills remain low.

“When it’s the middle of winter and 25C degrees inside without any heating on, it’s pretty good!”

Now in its second decade, the solar system has been trouble-free and easy to maintain, the panels requiring only an occasional spray of water to remove dirt and dust. Guaranteed for 20 years, they will more than pay for themselves before then.

“Make use of the resources out there,” Terrence advises. “Access free information offered by Council. Talk to retailers. They are generally happy to answer questions and demonstrate energy efficient options.”

“Although we’re both home more, being retired, our daily energy use is only 3 to 4kW, even in winter.”

So easy with expert advice and guidance

Lynne and Trevor in Anglesea


Lynne and Trevor admit to taking a long time to decide to install solar power. Although keen to save money on energy bills and do their bit for the environment, initially it seemed too hard – until they attended a presentation hosted by Surf Coast Shire Council.

Lynne describes the presentation as the light bulb moment that led the couple to subsequently install a 3.3kW rooftop solar system in April 2017.

“The installer guided us through the process, explaining the pros and cons of each decision. In the end, it was super easy and went smoothly,” Lynne says, admitting to being delighted when the first bill arrived.

“Despite a tariff increase, it was 30 per cent lower than the same billing period the previous year.”

The couple have since reduced their overall energy use and costs even further by making simple changes to the way they use household appliances and installing extra insulation in the roof.

“We run our washing machine and dishwasher during the day to take advantage of the free power provided by our solar panels,” Lynne explains.

“The insulation batts recommended by our plumber have made a really big difference too – especially in the upstairs area, which used to be so hot and stuffy during summer. It was unbearable.”

As a Powered By Positive advocate, Lynne offers the following advice: “Just take the first step. Seek out information, make enquiries, find suppliers and tradespeople who share your values and are willing to guide you through each decision along the way.”

“We were delighted when our first bill arrived. It was 30 per cent lower despite a tariff increase.”

Trust, support and quality foremost

Rodney in Jan Juc


Rodney and his family are used to strangers knocking on the front door selling solar panels. It’s happened so often, they’ve become immune to the high-pressure sales tactics and the promises of big discounts for signing on the spot.

“For us, it’s more about quality, support and trust in the supplier than it ever is about price,” Rodney admits.

After upgrading to an energy efficient heat pump hot water service several years ago, in 2018 Rodney and his wife Debra decided to install a 4kW photovoltaic solar system. Although the installer did an excellent job, especially in minimising the system’s visual impact, the result produced some initial teething pains.

“We experienced problems with an ‘over supply voltage error’. This came up as an alert on my phone via the app set up to monitor the system,” Rodney explains.

“The installer was terrific, responding quickly and contacting the local electricity distributor to help fix the problem.

“Apparently, the electricity grid can’t always cope with the extra power feeding in from a solar system and the voltage gets too high. As this can damage electrical equipment, the system’s inverter responds by reducing output.”

With the problem rectified, the new system is providing reliable energy and proving effective in reducing Rodney and Debra’s quarterly electricity bills – from around $500 to less than $300. This is on top of the more than $600 saved annually via their heat pump hot water service.

Rodney says the next step involves installing a battery to reduce the family’s reliance on grid power even more. “They’re a bit expensive at the moment but we are certainly considering it.”

“Since installing a 4kW photovoltaic system, we’ve cut our annual electricity costs by at least $800, which is on top of the $600 saved by our heat pump hot water service.”