A standard on geothermal testing methods is necessary because of the rapidly growing market in Europe of heat exchangers installation. Geothermal heat exchangers are used for heating and cooling and may be used in warmer and cooler areas throughout Europe. The use of geothermal energy leads to a reduction of coal and oil and therefore also of CO2 emissions. The drilling, installation of geothermal heat exchangers and testing for geothermal conductivity has to be determined by a standardised testing procedure.