One of the most environmentally damaging trends in terms of the way we use energy in buildings is through the widespread use of air conditioning. It is claimed that stabilised rammed earth (SRE) walls can be used as a building-integrated form of 'passive' air conditioning. The walls are 'building integrated' because they form part of the building structure and are load-bearing. Critically, they offer the ability to passively cool a building by naturally absorbing heat. They can store this heat and re-radiate it when the ambient temperature falls such as at night time. This property of energy storage is referred to as the thermal flywheel effect and can greatly increase indoor comfort levels. The porous nature of the SRE material is coupled with the presence of clay minerals that also enable the walls to passively control the humidity of a building's internal environment, i.e. a humidity-based version of the thermal wheel.To date there has been no comprehensive research investigation aimed at quantifying the passive air conditioning properties of SRE materials. Although the passive effects of SRE materials have been exploited & monitored in buildings before, no study has been conducted to find how the material properties control this, how to further increase them, or how to optimise them. For example, knowing how to control material properties such that the passive cooling & dehumidification could be specified would enable these to be tailored to the design of a building. The potential future outcome could be buildings that air condition themselves so that only a relatively small intervention from mechanical building services is required.SRE walls can be constructed using a wide range of raw materials such as natural sub-soils, quarry waste products, and recycled crushed aggregate. There is a definite need to quantify the relevant physical properties of these raw materials as discussed above. An extensive range of SRE test specimens will be produced and used to examine how soil grading & composition affects a range of thermal properties and moisture vapour properties. The experimental work will try to optimise the grading of the soils then look to enhance the physical properties through the novel addition of various other materials. Once the capacity for a given SRE wall to passively control indoor temperature & humidity can be sensibly quantified, a reduction factor can be calculated to determine how much of the conventional air conditioning requirement could be supplied by the SRE. The extensive database passive thermal & moisture properties in SRE materials will be used in computer modelling software such as IES Apache and ESP-r for dynamic modelling of the building's performance. This modelling, along with the laboratory scale experimental testing, will be verified by the full-scale testing of a life-size SRE test building constructed at the University campus by industrial collaborators Earth Structures (Europe) Ltd.