However, it was also revealed that since 2004, energy consumption has started to fall.
The head of the NAO, Tim Burr, welcomed the findings, but added that homeowners could still do more to improve their green credentials.
He said: "There are encouraging signs that the long-term growth in household energy consumption is reversing.
"But most of us still forget to turn off the lights in empty rooms, and building regulations to save energy in homes are not always followed."
Recent research by Ernst & Young found that the government's aims to tackle climate change could increase the cost of energy in the UK by around 20 per cent.
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