The transport coefficients of a one-dimensional (1D) disordered mesoscopic conductor are obtained with the use of the uncertainty principle. We calculate the thermopower and efficiency of the thermoelectric effect for several cases. Within the Landauer picture (a 1D disordered mesoscopic wire connecting two electron reservoirs) we consider two barriers connected in series and in parallel. In these systems it is possible to control the transport by applying electric or magnetic fields. Thus, we suggest several ways to manipulate the thermopower and the efficiency. We also consider systems which have a conductivity threshold (as a function of the electronic energy). Near such a threshold the thermopower and thermoelectric efficiency can be enhanced and the Wiedemann-Franz law breaks down.