New and renovated homes are rated according to the environmental impact of building and occupying them. The categories are: Energy: operational energy and carbon dioxide emissions Transport: location issues related to transport Pollution: air and water pollution (excluding carbon dioxide) Materials: environmental implications of materials selection, recyclable materials Water: consumption issues Ecology and land use: ecological value of the site, greenfield and brownfield issues Health and well-being: internal and external issues relating to health and comfort Credits are awarded where specific performance levels are achieved in each category. Various options are available to developers to gain these credits. The number of credits available in each category does not necessarily reflect the relative importance of the issue, as the total rating is calculated according to a series of weighting factors. 23 pages. For further information see http://www.breeam.org/ecohomes.html Reprinted with minor revisions 2003 - For changes since then (latest version April 2006), see http://www.breeam.org/pdf/SummaryEHChangesFrom2005to2006_v1.1April06.pdf