This publication contains two reports in a series produced by the International Energy Agency's Annex 28 to assist with the design of low energy cooling systems: 'Selection guidance for low energy cooling technologies' and 'Early design guidance for low energy cooling technologies'. Cooling is a significant user of energy in buildings, and its impact as a contributor to greenhouse gas emissions is enhanced by the fact that these systems are usually electrically driven. Annex 28 has explored passive and hybrid cooling technologies and strategies which have the potential to reduce energy consumption, and researched and documented tools to be used through the design process. This publication provides guidance on the initial selection of suitable low energy technologies, and presents a collection of simplified tools based on design charts and tables, and practical guidance, to assist with early design development of a technology.