In the recent years in Latvia is rapidly developing construction sector of residential buildings. Engineers have to give more attention to heating and cooling system’s technology in the buildings to stay competitive in the realty’s market. Every year is increasing part of geothermal heat pump’s use. An increasingly important economic factor and parameter in calculating the economic feasibility of geothermal heat pumps, is the extent to which a market exists for CO2 emissions in the country of operation. Just few years ago because of economical situation and climate in Latvia cooling systems in the residential buildings weren’t common, but now it is getting more popular. The latest version of geothermal heat pump’s use is implementation combined heating/cooling systems for residential buildings that can provide heating during the winter and cooling during the summer, which is very suitable for Latvian climate. In 100m depth where the temperature of the earth is constantly around 12°C, is possible to put pipes filled with a cooling agent and bring it up to the heat pump. In heating mode the heat pump compresses cooling agent pushes its temperature up to 55°C or even 70°C for the heating system. In cooling mode during the summer the heat pump only "heats up" the liquid up-to around 20°C and circulates it through the heating system and absorbs the heat from the rooms and brings it down to the earth again. The effect is that residential building will always have a delta of 10°C to the outside temperature. Special attention has to be given to the construction of heating/cooling system inside the building and its automatic regulation. Also ground heat exchanger type, its geometry and its efficiency has to be considered for each special case.