Townhouses could be the sweet spot for people looking for inner city housing that has enough room to comfortably work-from-home. The trouble is, this housing type is notoriously hard to make energy efficient. But a new residential development in Northcote, Melbourne, looks like it can change all that.
The pandemic has people yearning for more space but with land at a premium and the need to avoid urban sprawl that cuts into food bowls and natural habitats, the need for higher density housing hasn’t gone away.
These covid-affected conditions have the townhouse market looking healthy, according to the Dr Andrew Wilson, chief economist at Australian property platform Archistar.
While demand for all higher-density dwelling types are subdued compared to detached homes, which have benefited from government stimulus programs such as HomeBuilder, townhouse construction continues to outperform units. Townhouses now make up 42.7 per cent market share of overall higher-density development.
From a sustainability perspective, the trouble with townhouses is they are an inherently inefficient building typology because they span multiple levels, sometimes as many as three or four.
This creates heat transfer between the different levels with hot air rising to the top level, SDC director Ben De Waard explains.
“The bottom is hard to keep warm and the top warms up too much.”
SDC was the sustainability consultancy on a new residential development at Northcote, a northern Melbourne suburb, that will comprise 74 townhouses with an average NatHERs rating of 8 stars on a 12,000sqm site that was previously a bus repair shed.
The Northcote Place project, developed by Metro and designed by ClarkeHopkinsClarke Architects and Akas Landscape Architecture, will also have 80 per cent indigenous species in its landscaping as part of the project’s regeneration ambitions.
In sustainability-minded Northcote, the focus on low impact living has paid off, with 80 per cent of stage one residences already sold before construction has started.
Construction is set to commence soon after current demolition works are completed.
Unpacking the townhouse energy performance challenge
SDC’s De Waard says that achieving a higher thermal performance rating involves thinking carefully about the home’s thermal performance level-by-level and adjusting the window proportions, glazing and shading accordingly.
It’s also important to have doors that stop air moving between different levels, helping to slow down the heat transfer. The townhouses have sliding doors at the bottom or top of the staircase at each level, which act as an airlock and helped push the project’s overall energy rating from 7 to 8 stars. De Waard says it’s possible to separate the different levels and still have light coming in through by using glazing.
Making the best use of insulation is also important, as it’s relatively inexpensive compared to other key components such as high-performance glass. While De Waard wasn’t involved in the budget decisions, he says the client was able to source the windows and glazing at a competitive price.
“In the past, it’s been a deal breaker.”
The message for De Waard is that it’s not insurmountable to achieve high energy ratings in townhouses.
It will also be possible to replicate the high-performance design in other Melbourne sites, he adds, provided dwellings have the same orientation.
Less roofspace for generating solar
The other sustainability challenge with townhouses is that there’s less roofspace for generating solar power than a low-density freestanding home. Each of the Northcote townhouses will have 2.5kW system, De Waard says, which won’t quite meet a household’s energy needs. But thanks to the 8 NatHERS rating, the solar generated will go further than a system this size usually would.
The homes are also wired for batteries and electric vehicle charging should homeowners wish to install them down the track.
Other sustainability features include durable materials, north-facing living areas, cross ventilation, large eaves, ceiling fans in all bedrooms and living areas and rainwater tanks.
According to ClarkeHopkinsClarke multi-residential associate Janice Tan says, the team “delved deep with materials selection too, assessing provenance, wastage, supplier credibility and environmental performance ratings.”
The development also has permeable paths (allows rain to soak through the pavement into soil), community gardens and ample shared outdoor spaces “designed as habitat, not decoration”, Tan says.
There’s also considerable flexibility on offer, with two, three and four bedroom townhouses on offer so that people can stay in the area as their needs change.
“Beyond stars we wanted to create the most well-rounded sustainable townhouse living in Australia, and we were open about how to achieve that on this site,” Metro general manager, David Steele, says.
The development also ticks the 20-minute neighbourhood box with central mews for pedestrians and cyclists that provide a missing link between local bike paths, street furniture, access to the Merri Creek Trail and a new footbridge to the CERES Community Environmental Park.