[en] The power balance of a Helias reactor is analysed using empirical scaling laws which describe current stellarator experiments. Since neoclassical transport in Helias configurations is not prohibitive to ignition, anomalous transport determines the parameters of the ignited state. In the following study the plasma profiles are taken as given and the power balance with an external heating power is evaluated numerically. Three empirical scaling laws, LHD-scaling, Gyro-Bohm scaling and Lackner-Gottardi scaling are extrapolated to reactor parameters. Present experiments (Wendelstein 7-AS, ATF, Heliotron E and CHS) can be described by these scaling laws, in Wendelstein 7-AS preference is given to the Lackner-Gottardi scaling since confinement improves with increasing rotational transform. LHD scaling and Gyro-Bohm scaling do not satisfy the ignition conditions; an improvement of confinement is necessary. However, Lackner-Gottardi scaling meets the ignition condition and the operating window of the Helias reactor was found in the following regime: Major radius 20 m, average plasma radius 1.6 m, magnetic field 5 T, density n(0)=3-4x10²⁰ m^-3 and temperature T(0)∼15-17 keV. The fusion output power is 2.5-3.0 GW and the average value of β=4-5%. This lies within the MHD-stability limits of a Helias configuration. The effects of various parameter variations on the power balance (isotope effect, α-particle content, major radius, magnetic field) are also investigated. (orig.)