More rigorous energy efficiency standards are being applied to new homes in Victoria, but the same cannot be said for the state’s existing housing stock.

Except for homes undergoing a major renovation (altered by more than 50 per cent), no minimum energy standards for established properties currently exist — leaving many homeowners and renters shivering through winter, and sweltering in summer. (A 2015 study published in medical journal The Lancet found more people die from the cold in Australia than in Sweden.)

Sherrin Yeo and her family bought a heritage home in Ascot Vale, Melbourne with an energy rating of just 2.2 — a low but average rating for an existing home in Victoria. She always wanted to build a new sustainable home from scratch, but saw potential to update this one significantly to reach modern standards.

The renovations, designed by Brave New Eco and Geometrica, have increased the home’s performance by over 160 per cent.

We spoke to Sherrin to learn how she did it and her advice to other renovators.

Why did you decide to renovate your period home?

The house was certainly liveable, but it drove us crazy that we were on this amazing north-facing block with a park and views of beautiful trees from the garden, but we couldn’t see any of it.  We were always having to turn on the lights, even on a bright and sunny day, because the main bathroom and windowless laundry were located at the rear of the house and blocking the view. I’m assuming the previous renovation was done in a hurry to add some extra space, but the design was terrible.

What was the first thing you tackled through renovations?

We added an en suite to the main bedroom pretty soon after we moved in — we were sick of having a single bathroom with the toilet in the bathroom which was getting too tricky in a four person household.  We were able to tack the en suite onto the side of the main bedroom by building out to the property boundary.  We didn’t have the money to do the full renovation at the time.

When and why did you later decide to extend the home? 

We spent about five years thinking about and planning a bigger renovation, including discussing with about three different architects/designers.

We knew we wanted to open up the back of the house and have slightly more space, but we were also keen to avoid getting carried away and building a house with too much space that would be more expensive to heat, cool, and maintain.

House sizes in Australia are pretty crazy these days and a clever, small and efficient design was important to us in terms of sustainability, lifestyle and maintenance.

Was sustainability important to you when renovating?

I’m an engineer, so functionality and sustainability were always the number one priority for me! I always dreamt of building a sustainable house, but living in inner-city Melbourne, in a sustainable renovation, was the next best option.

Did you face any challenges in making the home more sustainable?

Finding a designer that understood our central drivers of sustainability, and keeping things a bit smaller than other clients might ask for, was more challenging than expected. Things have probably changed a bit in the last couple of years, but it felt like some designers valued aesthetics above thermal efficiency, sustainability and functionality.

It was also extremely hard to convince heater suppliers that we wanted a new electric heat pump hydronic heater rather than a new gas boiler. (There was a pre-existing gas hydronic system when we moved, but the boiler was really old and needed to be replaced.)

This was about three years ago, when the discussion about households going all-electric wasn’t nearly as mainstream as it is now. As an engineer working in renewable energy, I felt it was obvious that purchasing new gas appliances was a really stupid thing to do, but I got a ridiculous amount of pushback from all the heater suppliers I spoke to. I recall one of them describing me to our builder as ‘one of those,’ implying I was a crazy zealot for not wanting to install gas.

We now have a heat pump reverse cycle air conditioner, as well as an electric hydronic heater.  The hydronic heater was a bit of a luxury — the split system can heat the house just fine — but I prefer the conductive heat from a hydronic system.

In the end, we found a design team we were really happy with.

Can you outline some of the sustainable elements of the renovated home? 

The renovated home is all-electric including heat pump hydronic heating and hot water, and an induction cooktop — all powered by an 11.6 kW solar PV system.

We don’t have a battery, but we’re hoping to buy an electric car in the next few years once bidirectional charging options have improved, so we can use our car to power our house at night time.  We don’t drive much at all, so we’re happy to use up the battery life to power the house. In my mind an electric car can be thought of as a mobile battery rather than just a car.

Altogether, renovations have raised the home’s energy rating from 2.2 to 5.8 stars.

Was anything done to update the original rooms of the house?

We retrofitted insulation to the old parts of the house in the walls, ceiling, and floor. We weren’t able to get to all of the underfloor areas due to lack of access.

Otherwise, the front part of the house is in great condition and is pretty much original, other than us adding an en suite to the main bedroom. The bedrooms are all massive (probably bigger than we would have made them if we were building from scratch), but the kids love having the space.

What do you love most about your home now?

It is so comfortable to live in — cool in summer, and warm in winter. The design and colours have a really calming effect, and it is so lovely having the living spaces so connected to the beautiful outdoor spaces — both our own garden and the park behind us.  As a single-storey house, which is just the right size for our family, it is also really easy to clean and maintain, which is a massive plus!

It’s just a lovely, comfortable, calming place to live. I no longer look around and spend time fantasising about how to make the house more pleasant to live in.

What advice do you have for other homeowners interested in creating a more sustainable home?

Educate yourself, and don’t let anyone talk you out of what you want to do.  If you’ve done your research you’ll probably know a lot more than many of the suppliers you’ll be dealing with… I’m so glad I didn’t let heater suppliers talk me into using gas appliances!

Story in partnership with Momentum Energy. Momentum Energy are owned by Australia’s largest renewable energy generator and offer accredited GreenPower. Sign up to a greener power company.