It’s a great feeling to be so fossil fuel free

In 2002, Kevin and Penelope purchased a 1960’s brick veneer home. Older Melbourne homes tend to have poor energy efficiency, with no insulation in the walls or floors, only a small amount in the ceiling, and windows that leak and rattle in the wind. Over the years, Kevin and Penelope have been able to make vast improvements to their home’s energy efficiency.

Although a major goal was to retrofit to passivhaus standard (no heating and cooling required), they soon found the orientation of their house wouldn’t allow this. They considered powering their home off solar, but it was just far too expensive at the time. Instead, they invested in a solar hot water system and began to retrofit the house bit by bit as funds and opportunity arose. Rather than install expensive solar panels, they calculated that it would be more cost effective to invest in wind power, so they purchased enough shares in the Hepburn Community wind farm to cover their electricity consumption.

Not a cent in electricity bills

Three years ago, as solar system costs became much more affordable, they were able to install solar PV panels. Due to potential grid instability in prolonged heatwaves, they also chose to invest in a battery. The 9.6 kW panels generate much more power than Kevin and Penelope expected, and they only draw from the grid a handful of times per year – and that’s just to charge their electric car in winter. The panels are mostly east and west facing, because there was very little north-facing roof available, but it has the benefit of producing more power in the morning and afternoon when the grid demand is highest. The couple chose to go with PowerShop and they have not paid a cent in electricity bills since the installation.

First up, insulation and window upgrades

The work to retrofit their home began with replacing the insulation. In the ceiling, the old worn-out bulk insulation was replaced and foil installed between the rafters against the roof tiles to act as a radiation barrier; it’s highly effective, reducing radiant heat transfer by 90%.

The home’s “leakiness” was solved by replacing the old decaying windows with high-quality triple-glazed windows equipped with European-style closing mechanisms. To fill gaps between the walls and window frames, a formaldehyde-free foam was pumped into the wall space between the brick veneer and plaster walls.

While triple-glazing is a vast improvement on single-glazing, significant heat transfer can still occur in comparison to a well-insulated wall. On the south-facing walls, glazing was reduced substantially and insulation was achieved through reusing existing thermal curtains and sewing more for other windows. Finally, pelmet boxes were added to help minimise convective heat loss.

While Kevin and Penelope’s original aim was for a 10-star energy-rated home, they are quite comfortable in their estimated 8-star house, which uses only a small reverse cycle air-conditioner (designed for a bedroom) for all their heating and cooling.

Driving that’s powered by the sun

Owning an EV had also been a part Kevin’s plans for some time, and in 2018 he decided to go with a second-hand Tesla model S. His experience with Tesla’s customer service was exceptional. Kevin had been watching Tesla second-hand sales and jumped at the chance to buy when prices suddenly dropped dramatically, when there appeared to be an over-supply of second-hand EV’s.

The car Kevin selected was 18 months old, for which Tesla provided a four-year warranty. When he went to pick up the car, all signs of wear and tear - those little chips and scratches - he’d seen at first inspection were gone. The car had been beautifully repaired. A smart charger was installed at home to charge the car using excess solar, and the car is left plugged in during the week when it’s not in use. The majority of Kevin and Penelope’s driving is powered by the sun from their own solar panels. They say it’s a great feeling to be so fossil-fuel free, and we’d have to agree!