Residential buildings account for around 13 per cent of the Australia’s greenhouse gas emissions, and numerous studies have identified energy efficiency in residential buildings as one of the most cost effective approaches to climate change mitigation. There is an urgent need to identify the environmental opportunities available within this existing residential building stock. This paper surveys the key drivers influencing residential retrofitting for energy and water efficiency; outlines current and new retrofitting measures; and offers a practical cost guide to aid homeowners, industry groups and precinct managers to identify opportunities in residential retrofitting.