Abstract: Armoured vehicles are heavy masses of metal embodying many heat-generating systems, and are generally inhospitable enclosures for the crew they carry. The many tons of metal in their construction take up a mean temperature of the environment in which they are operating, and possess, as a result of that mass, a long time constant, which slows down the rate at which the temperature of the structure can change. The vehicle crew requires an environment controlled within fairly close limits to preserve their operating efficiency, and even their lives. This paper examines the factors influencing the effects on the vehicle in a hot climate; the relatively small environment envelope needed by the crew; and the steps that can be taken to achieve that envelope in such hostile conditions. Some engineering problems and their solutions are also examined, together with their effects on overall vehicle design.