Gwyneth Paltrow and her husband Chris Martin have both championed green issues, but an audit of properties measuring heat loss shows their north London house is "leaking" energy," the Times of London reported.
Thermal images of the residences of 10 high-profile green campaigners in England found that their heat loss was either worse or no better than that found in the average family home.
The couple's home in Belize Park wastes 1,020 kilowatt hours of heat a year, the Times reported. A spokesman for Martin refused to comment.
Paltrow backed the “Act Green” energy conservation campaign, while Martin tried to offset CO2 emissions produced by his band’s second album by planting a forest of mango trees in India.
Other houses surveyed included Boris Johnson, the mayor of London, and Sir David Attenborough, a broadcaster.