On hot days, most of the heat that gets into our homes is through the windows. On cold days, windows account for almost half the heat loss. High-performance insulating windows have been installed in Australian homes at a fraction of the rates for New Zealand, the United States and the United Kingdom.
As a nation we spend at least as much on renovations and retrofits as on building new housing. Upgrading the energy performance of existing homes should get at least as much attention as new homes to help make the transition to low-carbon living.