The book is intended for readers who are interested in energy saving methods. Most of it is written in popular form with minimal use of mathematics. According to the author, humorous drawings and statements will help to understand the essence of the main ideas, as well as to become interested in other, deeper books on thermodynamics and energy technology, including those given in the list of literature. Some provisions of the book are paradoxical, but confirmed by practice. The book can be useful to a wide range of readers - from schoolchildren to professors and chemical engineers.