The basic principle of heat transfer in temperature-modulated differential scanning calorimetry (TMDSC) and its influence on the measured signals is presented. Fundamentals of transfer theory are given within the framework of linear response. On this basis different calibration methods are suggested which enable to correct for the influence of heat transfer on the measured (effective) complex heat capacity in TMDSC. It is shown, that the complex calibration function is the reciprocal transfer function, which in turn is the product of the instrumental transfer function and the transfer function of the sample and its thermal connection to the TMDSC. Methods are given how to determine the transfer functions and how to correct the measured complex heat capacity properly.