Heat stress is expected to be of major concern in Swedish animal production systems in the future. The air temperatures in parts of Sweden are expected to correspond to today's temperatures in southern Europe, where livestock experience heat stress today. Excessive thermal load affects the welfare and health of pigs negatively. Confined pigs have limited physiological and behavioural abilities to loose heat. In an effort to loose heat during warmer periods pigs often choose to lay on the cooler slatted floor resulting in pen fouling, increased workload, disturbance of the pigs' resting behaviour and increased agonistic behaviours. Pen fouling also has negative impacts on the air quality (ammonia, airborne bacteria and respirable particles). Floor cooling in pens for fattening pigs has the potential to enhance the thermal and gaseous environment in the fattening pig barns resulting in improved pig welfare, performance and health as well as the working environment.