When it comes to custom renovations and new homes, it’s all too common for people to dismiss sustainability with the assumption that it will be too expensive for them. But whether sustainable homes are actually more expensive than their alternative is a bit more complicated than it seems. So, we thought we’d have a crack at answering this question ourselves – and explain why it’s not as simple as a ‘yes’ or ‘no’.
WHAT ACTUALLY MAKES A HOME SUSTAINABLE
To even begin answering the question, we must first explore how sustainability should be defined. While there are some standards available, like Passivhaus, what’s actually ‘sustainable’ will be different for every person. At Arklen, we prioritise longevity but also understand that sustainability is a thought process rather than something with a stringent set of rules. Every client and their home is different, so the approach to sustainability should change accordingly.
To simplify this a bit, sustainability is much more than the design and materials of a home. It must also consider how the home will operate in the long-term for the specific clients it’s being built for. Just as transportation emissions may negate the sustainability of an eco-friendly product imported from the other side of the world, the same might be said for one that has a significantly shorter lifespan than its ‘unsustainable’ alternative.
Similarly, what’s more sustainable in one home may be less so in another. Solar heat pump hot water systems are typically more sustainable than instant gas. But in our Vivaldi Street project, which is a holiday home, it would have been inefficient to include a system that’s constantly running, even when the clients aren’t there. So instant gas, which can be switched off, ended up being the more sustainable option. One must consider how they’ll use a home before deciding how to make it sustainable.
One of the stunning bathrooms at Vivaldi Street, with instant gas.
THE COST OF DESIGN
If you’re building a custom home, there shouldn’t be a cost difference between a standard and sustainable design. What’s important is finding a designer that you like and can consider sustainability—which most designers should be able to do these days. They can then help you decide how to prioritise sustainability in a way that works for your lifestyle. To reduce the overall cost, the best advice we have is to prioritise usable good-quality spaces over size, opting for a smaller house with a more efficient layout. In doing so, you’ll also be upping your sustainability game, as your project will need fewer materials and a smaller block size that reduces urban sprawl.
Bushy Road, one of our many projects that prove smaller homes can be just as good, if not better, than larger ones.
LET’S LOOK AT SOME NUMBERS
The reason it’s often difficult to answer if sustainable homes are more expensive is because there are two sides to the picture. Upfront, when you’re building your home, sustainable choices can cost more. But further down the line, when operational costs and longevity come into play, it’s usually the opposite and those sustainable choices end up making the home more affordable. Let’s look at a few examples.
Termite barriers
When it comes to protecting your home against termites, there are typically two options to choose from. Chemical barriers involve a reticulation line filled with chemicals that repel or kill termites. They also come with significant environmental risks including soil and groundwater contamination. Physical barriers, on the other hand, simply block termites from accessing the home with a barrier of metal sheeting or mesh and are usually the more sustainable choice. As you may have guessed, chemical barriers are usually the cheaper option, coming to about 20% of the cost of physical barriers. However, they also require annual treatment and inspection, while physical barriers usually last the life of the home and only require inspections to maintain their warranty. So, a few years down the line and those costs will have reversed with the chemical barrier coming out more expensive.
Installing a mesh termite barrier.
Structural timber
Another good example is the different levels of treatment for structural timber. At Arklen, it’s a non-negotiable on all our projects that any structural timber has an H3 level of treatment. This is a step higher than Australia’s minimum requirement of H2 but makes a big difference in its protection against termites and weather. Both have the same labour costs, but H3 treated timber costs an additional 25% at checkout (as of October 2024). More expensive upfront, yes, but we have no doubt this extra cost is worth the additional protection and longevity it provides, reducing costly repairs and/or replacements in future.
A higher rating helps to protect the timber from the elements during the build, which can make a big difference to longevity.
Solar
Now onto the one that you’re probably the most curious about. For this, we’ve gotten in touch with our clients at Dalgety Street to see how the inclusion of solar has impacted their power bills. For the 224sqm home, they spent $4,107 on a solar system with battery storage. Five years later, and they’ve found that the system saves them an average of 71% on their power bills each year. And this is just one example; the average payback period of most solar systems is only 4 years. After that, it’s all just savings.
Dalgety Street’s contemporary interior.
THE SUSTAINABLE INCLUSIONS TO PRIORITISE
If you don’t have the budget to prioritise sustainability throughout the home, a few sustainable inclusions can still be effective. The top three that we’d recommend considering are solar panels, double glazing and insulation. Solar panels are undoubtedly the easiest as they can make a difference on most homes and require minimal works. Insulation and glazing are also comparatively small jobs that can still lead to long-term savings. We do recommend getting advice for both these options, though, as their effectiveness may differ depending on the home design and its orientation.
DID THAT ANSWER THE QUESTION?
Ultimately, sustainability is a long-term goal, and so the cost-savings should be considered in the same way. While the upfront costs may often be more expensive, sustainable homes offer much better value for money, and almost always lead to savings in the long-term. We understand how complicated this can all seem, though, which is why we can work closely with you throughout the design and build. We can help you decide when the upfront costs are worth it or source alternative options that find a balance between those upfront costs and sustainability.