Since 1998, the Department of Education and Science has been using a process of design, awareness, research and technology known as DART to develop energy efficiency in educational buildings. Currently all primary schools built in accordance with the Department's primary schools technical guidance documents are capable of being up to 2.3 times more energy efficient than schools built to international best practice. In this article, the author explains how Ireland has incorporated low energy design into primary and post-primary schools and gives an overview of projects that have helped inform this approach. (Contains 1 figure.)