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.