This book aims at presenting compact knowledge of low energy buildings. The issues discussed include, among others: • architectural elements of energy-efficient houses, such as location shape and functional layout • construction of opaque and glazed partitions, diminishing heat losses and enabling the effective use of solar energy • construction of envelope joints minimizing thermal bridges • implementation of design principles in practice, presented by examples of single-family buildings, multi-family housing estate and public utility buildings • energy-efficient technical systems using renewable energy sources. The content of the book may be important to all of the people taking part in building processes, especially designers and contractors. The publication is also addressed to students and individual investors, wanting to increase their knowledge about low energy buildings and their components.