The Coolhouse project is a European Commission supported project in the ENERGIE Programme, which tests the viability of alternatives to air conditioning using passive and low energy cooling and ventilating techniques with the aid of computer simulation, before building the proposed designs and monitoring them over the summer period. Possible natural ventilation and cooling strategies originally considered included wind catchers, wind towers, earth tubes, and rock stores. The Coolhouse project aims to demonstrate that such strategies can be low-energy, practical and provide comfortable internal conditions for the occupants. One objective is to provide economic and environmental arguments to justify the cost (life cycle versus capital cost) of the systems and to design and construct systems that are easy to replicate at reasonable cost.