All too often we come across people who believe that they’re not able to build a passive house because they have a relatively small budget. But, while passive houses can be costly if one opts for all the bells and whistles, they certainly don’t have to be. In fact, our building partner ISMART just delivered a family home in West Leederville for under $500k, and in just 7 months at that! So, as a prime example of how a standard Passive House home can be delivered at an attainable price point, let’s look at how we did it; and how you can do it, too.
Passive house experience
As you’re likely aware, a passive house is much more complex than a standard home. The designer or architect needs to consider countless elements—from an airtight building envelope and ventilation to high-performance doors and windows—to ensure the end product is, indeed, passive. And if you want to ensure your architect has the knowledge to cut down on costs, it’s even more important that they have extensive experience. With this, they’ll understand where shortcuts can be taken, and what materials and products will offer high-performance results whilst remaining cost-efficient.
An experienced architect should also have the industry knowledge to find a good team of builders at good value. If possible, make it a priority to find such builders early, as they can provide important advice on costs and detailing during the planning process that will ensure you have a smoother construction experience. Of course, they should be paid for any time they work on your project to ensure they can prioritise it themselves, and spend the time needed to provide quality advice.
Size and floorplan
It’ll be of no surprise to hear that the size of your home will have a big impact on your budget, so try to think practically about your home and be prepared to compromise on space. Flexible design can also be a gamechanger, where rooms can have multiple uses. In this home, for example, we combined the bathroom and laundry to save space.
As the walls of a home (along with roofs and glazing) tend to be the most expensive part of a home, the overall floorplan should be designed to minimise these. Square or rectangular homes are ideal as they have the best floor-to-wall ratios, along with open-plan designs with few interior walls.
Then we come to the roof structure, which should remain simple and affordable wherever possible. In this West Leederville design, the majority of the rooms have a simple, cost-effective truss roof. We only opted for cathedral ceilings in the living areas where they’d have the most impact and would allow northern light into the rooms through high windows.
Beautiful design choices are still possible in budget-friendly designs.
Material choices
When choosing the materials for a budget-friendly passive house, functionality and cost should play just as much, if not more, of a role as design. But sometimes, this doesn’t simply mean choosing the cheapest material. One of the best things we did with this project was to work to standard material sizes. The exterior cladding is set to the maximum sheet sizes so we could save the labour costs of cutting each sheet and reduce waste. It also looks great aesthetically as there are no joins. We did the same for windows and doors, as standard sizes will always be cheaper than custom.
In this project, we also substituted the expensive lift and slide doors that we usually use, for French doors. These are still highly functional as they seal airtight, have lots of glazing and can open outdoors, while still being cost-effective.
Next, let’s consider how to reduce the cost of cabinetry, which are one of the most expensive fixtures. In this project we designed a kitchen with minimal cabinetry to ensure it was still highly efficient without being excessive. To do this we opted out of a kitchen island—which also helped open up the space—and instead chose to wrap the cabinetry around the walls in an L-shape. These were all simply designed with common materials to reduce the complexity for the cabinet makers and reduce the cost.
All other materials and finishes remained very simple, like carpet in the bedrooms, polished concrete flooring and, finally, simple plasterboard and paint on the walls. This led to a clean, modern design that remained affordable and allowed us to make other more expensive decisions, like high-flushed door frames to add to the design.
External additions
External additions can be anything that’s outside the main thermal envelope of the home, including exterior patios, garages, pools and landscaping. However, it’s the thermal envelope of the main house that should always take priority in a passive house, as you’re unlikely to ever change it. Then, when the funds are available, you can think about external additions. In this project, for example, our clients came up with the funds for the garage half-way through the build, so that’ll be completed very shortly after the main home.
Ultimately, designing a passive house on a budget is all about prioritisation, to spend money where it’ll have the most impact, and save money everywhere else. If you’re worried about whether you can afford it, it’s best to work with an architect as early as possible. They can even help you choose the right block, with consideration for slopes, orientation, retaining walls and overshadowing which can all have significant impacts on building costs. If you have a budget passive house project in mind, no matter the stage you’re at, get in touch with us at Leanhaus to see how we can help.
Written by Ellie Prober with Ben Caine.