Heat recovery can also be used in the opposite direction – to cool the building from the outside cold source. Since Latvia is located in the northern part of Europe, we have not had a great need for cooling solutions, but as the summers get hotter, the demand will only grow. The cold energy in the ground and water bodies is most often used as a source of cold because using it has low production costs and greater energy savings compared to other cooling methods. In groundwater is chosen as the resource source, it is necessary to consider the drilling to obtain water at a temperature of 6–12 °C, which in some cases can then be used as technical water.