A method of limiting power consumption in a plurality of climate control appliances (11, 12, 13), each of which is communicably coupled to a controller, the climate control appliances having a running cycle of predetermined length, the method including the steps of: setting a cap for the total power consumption of the appliances; setting a set point for a climate parameter for each climate control appliance; and before the end of each running cycle, each climate control appliance (11, 12, 13): measuring a climate parameter associated with the area around said climate control appliance; predicting whether said appliance being active for the next running cycle will result in the climate parameter being closer to the set point for said appliance than if said appliance is inactive for the next running cycle; and if it is predicted that said appliance being inactive results in the climate parameter being closer to the set point, maintaining said appliance in an inactive state for the next running cycle; if it is predicted that said appliance being active results in the climate parameter being closer to the set point, said appliance communicating with the controller to request permission to be in an active state for the next running cycle; the controller: selecting some or all of said appliances which have requested permission to be active for the next running cycle such that said cap is not exceeded and taking account of the predicted deviation of each appliance from its set point if it is not activated; and communicating with said selected appliances to cause them to be active for the next running cycle. setting a cap for the total power consumption of the appliances; setting a set point for a climate parameter for each climate control appliance; and before the end of each running cycle, each climate control appliance (11, 12, 13): measuring a climate parameter associated with the area around said climate control appliance; predicting whether said appliance being active for the next running cycle will result in the climate parameter being closer to the set point for said appliance than if said appliance is inactive for the next running cycle; and if it is predicted that said appliance being inactive results in the climate parameter being closer to the set point, maintaining said appliance in an inactive state for the next running cycle; if it is predicted that said appliance being active results in the climate parameter being closer to the set point, said appliance communicating with the controller to request permission to be in an active state for the next running cycle; measuring a climate parameter associated with the area around said climate control appliance; predicting whether said appliance being active for the next running cycle will result in the climate parameter being closer to the set point for said appliance than if said appliance is inactive for the next running cycle; and if it is predicted that said appliance being inactive results in the climate parameter being closer to the set point, maintaining said appliance in an inactive state for the next running cycle; if it is predicted that said appliance being active results in the climate parameter being closer to the set point, said appliance communicating with the controller to request permission to be in an active state for the next running cycle; the controller: selecting some or all of said appliances which have requested permission to be active for the next running cycle such that said cap is not exceeded and taking account of the predicted deviation of each appliance from its set point if it is not activated; and communicating with said selected appliances to cause them to be active for the next running cycle. selecting some or all of said appliances which have requested permission to be active for the next running cycle such that said cap is not exceeded and taking account of the predicted deviation of each appliance from its set point if it is not activated; and communicating with said selected appliances to cause them to be active for the next running cycle.