The Coolhouse project is exploring the viability of alternatives to air-conditioning in southern European countries using innovative passive and low energy cooling and ventilating techniques, with an emphasis on ground cooling. The project will demonstrate a variety of passive cooling techniques and the use of ground cooling systems for housing in Crete and Portugal, a nursing home in southern France and a community centre in Italy. The project partners include architects, energy designers, social housing providers and developers, the project will last 48 months. One of the principle objectives is to determine the potential of passive and low energy control of internal temperatures with the aim of providing occupant comfort, while reducing energy consumption and CO2 emissions. The Coolhouse partners aim to design ground cooling systems that are low energy, practical, low maintenance and easy to replicate at reasonable cost. The paper will describe the design parameters that influence the efficiency and cooling capacity of the ground cooling system, and cleaning, maintenance and possible drawbacks will also be discussed. Each of the projects will be described, with an emphasis on the technical aspects of the project in Portugal as it is the most advanced.