It is necessary to evaluate quantitatively the thermal performance of doors during the design stage and reflect it to their specifications. Calculation method is more appropriate than test method for the evaluation. In Japan, however, no method is established nor recognized officially for the calculation of thermal transmittancc (U-valucs) of insulated doors. Although the methods responsible for the purpose arc currently discussed in ISO and ASHRAE, they are not always applicable to the details of the doors manufactured in Japan. In this report, the calculation method which covers the various kinds of insulated doors developed in Japan as well as is compatible to that in the ISO draft is proposed. To examine the accuracy of the proposed method, U-values are computed for recently developed doors and comparisons are made with the test values together with the discussion on the discrepancies between the values.
