The Watervilla

Dutch architect Herman Hertzberger says traditional houseboats were his inspiration, but notes that, as places to live, they're uncomfortable. His Watervilla – more a house than a boat – rests on a hexagonal frame of steel tubes roughly two metres in diameter. This not only keeps the house stable even in the rough waters of the North Sea, but also allows it to drift at will. The base supports a three-storey structure, containing three bedrooms, a bathroom, a living/dining room and a kitchen, and a large open space on the top level that can be used as an office or spare bedroom. An eight-metre-long gangway provides access from shore.

Obviously, it's possible to navigate the Watervilla, and it can rotate 90 degrees to capture the best solar orientation, but it doesn't have many high-tech systems in order to keep costs down.

Spitbank Fort

Spitbank Fort is situated a mile offshore at the mouth of one of Britain's busiest harbours. Started in 1864 as a defense against the French military, it is one of the most unusual military structures in the world.

Current owner Michelle Jacolow saw Spitbank Fort for sale five years ago and knew immediately that she had to have it. 'It's just the most amazing home. Everyone dreams of living by the sea, but how many people can say that they actually live in it?' she says. 'Everywhere I look, I have the most glorious views of the untamed ocean. I wouldn't change it for the world.'

Hockerton

The Hockerton Housing Project in Nottinghamshire: the first earth-sheltered housing development in the UK. This terrace is a self-built co-operative run by a team of five committed families.

Unlike Mole Manor, which is dug into the ground, this project is built into a south-facing hill. The residents generate their own clean energy using a wind turbine, recycle waste materials and cause no pollution or CO2 emissions. But perhaps the most remarkable feature of Hockerton is that using solar energy makes it completely self-sufficient when it comes to space heating and hot water.