An eco-friendly housing project which produces cheap electricity has won a sustainability award.
The four bungalows are housing association properties
The Honingham Earth Sheltered Social Housing Scheme in Norfolk consists of four bungalows insulated by layers of plants to retain heat.
The buildings have no conventional heating or cooling system and energy bills are as little as £4 a week.
The Royal Institute of Chartered Surveyors (RICS) Sustainability Award 2006 considered 41 other nominations.
Simon Pott, chairman of judges, commenting on the project, said: "As energy and sustainability concerns rise up the agenda, this project sends out a powerful message to us all: sustainable housing can be commercially viable and deliver value for money."