Six years ago, Emily Walter and her husband wanted to upgrade their house in Canberra’s Macquarie suburb. The couple with two children, lived in an “ex-govie,” or government brick veneer house that was stock standard in the national capital in the 1960s.

The cookie-cutter rectangular house lay north-south on their block, copping the full glare of Canberra’s harsh morning and afternoon summer sun, and with just one north-facing window to let warmth into the house in winter.