While some parts of the development industry push back at the idea of increasing energy efficiency requirements for new homes on the basis of cost, a Western Australia architect demonstrates that dialling up specifications for net zero is do-able and affordable. And he’s now offering his plans online for others.
Innovation began at home for Matt Delroy-Carr, principal of MDC Architects. Now, he’s aiming to shake up Perth’s project home sector through making affordable architectural designs for energy efficient and net zero-capable homes available for small builders and home buyers.
It all began when he was designing a new home for his family.
Delroy-Carr wanted to demonstrate that a small footprint home with maximum garden space and passive performance that was adapted for the local Perth climate could be achieved as an affordable build.
Working with a sustainability consultant to test the design, he discovered it performed well and had a low net footprint for both embodied and operational carbon.
The results also brought net zero systems to the forefront of his thinking, kicking off a learning process and R&D to understand why it performed so well and what improvements were possible to get to net zero.
“Net zero housing is really not mind-blowing,” Delroy-Carr tells The Fifth Estate. “Good design and small housing footprints tick off everything essential.”
Costs and trade-offs
The first home, which he and his family have been living in since 2022, has a footprint of 145 square meters. That’s roughly half the size of the average Perth detached home. It scored 7.2 NatHERS.
The construction cost came in at under $500,000 for an on-ground slab with a double-brick lower storey and timber framed upper storey with reverse brick veneer.
Some decisions were made around specifications to minimise operational and upfront or embodied carbon, with CERCLOS software used for the lifecycle analysis (LCA). Painting and maintenance, for example, add to lifecycle carbon, so materials were chosen that minimise the need for these.
Investigations into materials also examined basic lifecycle trade-offs.
For example, if high embodied carbon materials are used, is there a reduction in operational carbon? And if lower carbon materials are used, what does this mean for operational carbon?
MDC has designed and completed other energy efficient, low carbon homes and refined the design and specifications to create a suite of “off-the-shelf” affordable home designs for three—and four-bedroom plus study configurations.
Scaling the concept
Delroy-Carr explains that the New House Plans also integrate garden design as part of the site plan. The goal is to have liveable, adaptable and functional internal and external living space, achieve around 8 star NatHERS, and provide architecture that is climate-adapted and suitable for smaller sites. Using basic construction systems, building them could come in at around $400,000-$550,000, depending on the size chosen.
The high-performance nature of the homes means that once solar is added, operating at net zero becomes feasible.
The plans are now being sold via the practice website for $4999 for design and basic specifications for building systems, or $6999 for the design and specifications including CAD files and bill of quantities plus 3D renders.
Already, more than half a dozen clients have downloaded the plans, which he says means they have “paid themselves off” in terms of the investment in creating them.
He and his team are also working through user feedback to ensure they are applicable for a range of sites and home buyer needs. Recently, a courtyard home was added that maximises garden space on small blocks.
Giving small builders a market edge
The design initiative will also work well for smaller home builders struggling to compete with the big volume home operations, Delroy-Carr says.
One builder has already adopted the plans for a project that is now under construction and is “keen on doing more.”
“It is scalable for him, and it meets the market for affordable homes. We’re trying to find (more) smaller builders that want to work at that cost bracket.
“Partnering with builders is the way to go. Their customers often don’t want to pay $50,000-plus for architectural designs.”
Originally, he and his team thought double brick type homes would be the drawcard, as Perth is the “double brick capital of Australia”.
However, the builders showing the most interest are delivering timber-framed, lightweight construction. Products such as Hardiplank, weatherboard and corrugated metal cladding are popular for external facades.
This resonates to the pre-war Australian architectural vernacular of high ceilings, verandas, louvre windows, a sense of proportion and consideration of how a home addresses the street.
Delroy-Carr says it is both “interesting and fun”, providing contemporary spins on those traditions.
Embedding principles in policy
The thinking behind the home designs was also brought into play in his work with the WA government, consulting on the Medium Density Housing Code released in 2024. Medium density in Perth is largely about groups of townhouses and one to two-storey unit blocks, he says.
The main goal of engaging with the code was demonstrating the possibility to create “smaller, decent houses with decent gardens”. See our story: https://thefifthestate.com.au/innovation/design/new-code-to-boost-the-missing-middle-in-western-australia/