Interior design writer Elizabeth Wilhide gives practical advice on eco-sound materials along with 15 illustrated case studies showing how other homeowners have tackled the issue of conservation.

This is more service manual for the home than glossy coffee-table book, although it is choc-full of lavish colour photographs. From the start, it sets out to explain the eco ethos in relation to how we live in our homes.

What do people mean when they talk about 'ecological design'?

Wilhide explains that a lot of the terms now in common use are being bandied about - not least by some companies claiming spurious ecological benefits attached to using their products.

In it's true form, ecological design is the kind that makes use of resources that come from the earth in such a way that they can be returned to the earth without causing harm, and in a cycle that echoes the natural systems of living things.

'Sustainability' - a related but not exactly equivalent concept - implies using resources, including land and energy, with maximum efficiency, at a rate that does not compromise the needs of future generations.

While 'green' has become a blanket term for a range of environmentally friendly approaches, 'natural', and to some extent 'organic', are even less precise, particularly since such terminology has been increasingly appropriated by companies seeking to 'greenwash' their products.

In design terms, says the author, 'natural' and 'organic' have also been used to describe buildings that echo the colours and forms of the natural world, which is not the same as designing to protect the natural environment. In one sense, eco design is a way of going back to "rst principles, adds Wilhide.

In these style-conscious times, it is easy to become obsessed with the latest trend and to forget that the purpose of a house is to provide shelter. There are chapters in the book on choosing environmentally friendly materials, from paints to plaster, and including the old domestic virtues of thrift and household economy.

A handy manual for the 21stcentury homeowner for whom conservation must increasingly become a way of life.

'Eco' by Elizabeth Wilhide is published by Quadrille, ¤23