When heat energy is stored in clay, the geotechnical properties will change as a result of changing temperature. This paper presents results from laboratory tests on sulphide rich silty clays. The tests are ordinary oedometer tests and creep tests in the temperature range 5 to 55°C. It is shown that even a small deviation of the testing temperature from the in situ temperature is of importance for the results. Based on the test results, a creep-temperature equation is proposed