Instruct: Classify the given Amazon review as either positive or negative.
Query: very helpful book

The Solar House presents a detailed overview of passive solar design with specific region-based recommendations. I found that the technical information was well-researched and presented in an accessible way. There is a very helpful section on backup heating systems, which provides a basis for comparing the many options such as conventional gas and oil fired fixtures, radiant floor, masonry stoves, etc. This book should help people to design homes that are very energy efficient and comfortable to live in- the best of both worlds.