NBN EN ISO 13789:2008

ISO 13789:2007 specifies a method and provides conventions for the calculation of the steady-state transmission and ventilation heat transfer coefficients of whole buildings and parts of buildings. It is applicable both to heat loss (internal temperature higher than external temperature) and to heat gain (internal temperature lower than external temperature). For the purpose of ISO 13789:2007, the heated or cooled space is assumed to be at uniform temperature.