I think it depends on your personal circumstances and how strictly you want to follow to the plans - I suggest talking to a planner or a builder to get an idea of costs

We're looking into this but haven't decided if we will use these plans or use an architect with experience in passive solar design. I've started preliminary discussions with a builder who has experience with passive solar houses, although he predominantly does small scale volume building. Hoping he can bring his purchasing power and systems to this project but allow us the flexibility to create what we want. He's enthusiastic about passive solar design so that's a start. We haven't discussed these plans yet, but at a rough estimate he's suggested in the low to mid $300,000s for a 200m2 house including garage, polished concrete floors, reverse brick veneer, increased insulation, quality kitchen appliances, with BAL up to 19, static fire tank. Not including PV panels, driveways, landscaping. Does include hydronic heating.

Of course it does depend on the finish you want, type of builder you go with etc. Could easily be much more than what we were quoted. A discussion with a different builder, for similar sized house, to increase insulation as required, $2-3,000, add double glazing, $14,000, polished concrete floors, similar to fairly standard tiles or carpet. These are very rough estimates.

things that would also increase the cost, lots of glazing on north elevation, higher ceilings than standard project home. Large eves to the north, the room sizes are generous, internal masonry wall, draft proofing.

Life time running cost would be much lower than conventional house. I live in a cold climate so thermal comfort is important.

We have been looking at this site too. The 3 bed with courtyard is particularly appealing. Would love to know if anyone had used these designs.

We went to our builder with the courtyard design but was advised it would be too expensive due to the complicated roof you would require. We are building the 2 bedder with study but making the study a “bedroom”. Only in early stages

I’m seriously looking at this too. I was ideally wanting a strawbale house but also loved the courtyard design. I haven’t found anyone who has actually built any of these homes though. Would love to see one in situ.

The current issue of Sanctuary Magazine has the Banskia rectangle with small mods built in it. It's really nice and cost $300,000 (excluding off-grid tech - extra $100k).

https://renew.org.au/sanctuary-magazine/sanctuary/sanctuary-issue-52/

I also eyed off the courtyard design and wondered about roof, but also why North wall of lounge had no windows? Looks gorgeous but would need some tweaking.

Really want to see more examples of finished builds though.

There’s a website for the house: https://harmonyhouse.com.au/house.html great case study

I also found these people on Insta https://www.instagram.com/explore/tags/house255/

and smyleeblue - would love to see your progress.