The objective of Heating And Cooling Knowhow and Solutions (HACKS) is to achieve market transformation for heating and cooling (HAC) appliances by motivating consumers to replace old and inefficient equipment with new energy efficient equipment; and to encourage solutions that consume less fuel, lower energy bills and improve users’ comfort and health. In the EU, almost half of all buildings have individual boilers installed before 1992, with efficiency of 60% or less. The associated energy savings of a speedy replacement are immense. To achieve these goals, 17 HACKS partners in 15 countries will raise awareness on HAC economic and environmental benefits via a communication campaign, and 15 dedicated national online platforms that will provide clear, understandable information. The focus will be on HAC appliances (e.g. boilers for space and water heating, local space heaters, etc.), but also on solutions that lower the energy consumption and avoid the installation of new equipment (shading systems, thermostats, taps and showerheads). HACKS will engage consumers by assisting them during the purchasing process of new HAC equipment. The online platforms will provide tools to receive customized information, interactive comment functions, product information, and direct links to the suppliers of the product. The online platforms will also provide guidance on how to improve consumers' situation while avoiding the purchase of unnecessary equipment as well as how to use and maintain devices. Finally, HACKS will work with all relevant stakeholders (“the multipliers”) that participate in the decision-making process of consumers by setting up strategic partnerships to promote and facilitate the purchase of energy efficient installed appliances. HACKS will place a strong emphasis on installers, retailers and consumer organisations because of their proximity to the consumers and capacity to involve and bring guidance on energy efficient equipment directly to them.