Method of testing the thermal performance of at least one object , the method comprising the steps of: - providing at least one initial temperature curve which has been obtained by: - providing at least one first enclosure having side walls lined with thermally insulating material, - arranging a temperature sensor configured to monitor the temperature inside each of the at least one first enclosure , - arranging the at least one first enclosure inside a first furnace , - increasing the temperature of the first furnace in accordance with a predetermined test curve while monitoring the temperature inside the at least one first enclosure and thereby obtaining an initial temperature curve for each of the at least one first enclosure , and - storing the at least one initial temperature curve in a database for later use, - possibly repeating the above steps if more initial temperature curves are needed for the subsequent steps, - placing the at least one object inside a second furnace for testing of the thermal performance of the at least one object , - heating the second furnace in accordance with one of the at least one initial temperature curve while determining a resulting test parameter for each of the at least one object , the test parameter being an indicator of the thermal performance for each of the at least one object if it had been placed within the at least one first enclosure . - providing at least one initial temperature curve which has been obtained by: - providing at least one first enclosure having side walls lined with thermally insulating material, - arranging a temperature sensor configured to monitor the temperature inside each of the at least one first enclosure , - arranging the at least one first enclosure inside a first furnace , - increasing the temperature of the first furnace in accordance with a predetermined test curve while monitoring the temperature inside the at least one first enclosure and thereby obtaining an initial temperature curve for each of the at least one first enclosure , and - storing the at least one initial temperature curve in a database for later use, - possibly repeating the above steps if more initial temperature curves are needed for the subsequent steps, - providing at least one first enclosure having side walls lined with thermally insulating material, - arranging a temperature sensor configured to monitor the temperature inside each of the at least one first enclosure , - arranging the at least one first enclosure inside a first furnace , - increasing the temperature of the first furnace in accordance with a predetermined test curve while monitoring the temperature inside the at least one first enclosure and thereby obtaining an initial temperature curve for each of the at least one first enclosure , and - storing the at least one initial temperature curve in a database for later use, - possibly repeating the above steps if more initial temperature curves are needed for the subsequent steps, - placing the at least one object inside a second furnace for testing of the thermal performance of the at least one object , - heating the second furnace in accordance with one of the at least one initial temperature curve while determining a resulting test parameter for each of the at least one object , the test parameter being an indicator of the thermal performance for each of the at least one object if it had been placed within the at least one first enclosure . <EOS>