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tokens: ULIRGs. They find the presence of molecular outflows with mass outflow rates of several 100 yr, which are similar or larger than the star formation rates in these systems. For the ULIRGs that we study in this paper, we derive outflow rates of molecular gas that are a factor of a few lower than the star formation rates (Sect. 4.1 ). Therefore, our H results appear at odds with the CO results from Cicone et al. (2014) . Of course, the H 2.12 m line only traces a small fraction of the total molecular gas mass, and its strength is subject to the local gas temperature and excitation (see, e.g., Rigopoulou et al. 2002 ). Complementary CO or mid-IR H observations of our sample sources are needed to further investigate the hot-to-cold molecular gas mass ratio. Some of the most spectacular molecular gas outflows in ULIRGs have been detected with the Herschel Space Observatory in the OH line (e.g., Sturm et al. 2011 ; Spoon et al. 2013 ; Veilleux et al. 2013 ; González-Alfonso et al. 2017 ). The outflow velocities that we observe in the H line with SINFONI are within the range of the OH outflows detected with Herschel. However, the mass outflow rates derived from OH measurements by Sturm et al. (2011) and González-Alfonso et al. (2017) are nearly ubiquitously 100 yr. Our SINFONI data suggest also here that either molecular outflow rates in nearby ULIRGs are much more moderate than predicted based on OH studies, or that our assumed hot-to-cold gas mass ratio for H outflows in ULIRGs is too large. Alternatively, the OH studies may trace faster outflows that originate closer to the galaxy core, with higher and smaller . González-Alfonso et al. (2017) indeed found evidence for higher maximum outflow velocities seen in OH compared to CO in several nearby ULIRGs. According to González-Alfonso et al. (2017) , this could suggest that OH and CO trace outflows in different regions of the galaxy. After all, they argue that as the outflowing gas expands and breaks up into clumps, it will “cover a decreasing fraction of the far-IR continuum”. Unlike the CO, the OH molecules are radiatively excited, and hence “produce lower absorption and emission” the further out the gas flows ( González-Alfonso et al. 2017 ). This scenario may also explain the fact that the molecular mass outflow rates that we derive from H appear on average lower than those based on OH studies. Our results suggest that consensus has yet to be reached on how effective molecular gas outflows are in influencing the star formation properties of nearby ULIRGs. We argue that detailed 3D-imaging of the different gas phases is a valuable tool to help determine the evolutionary role of multi-phase gas outflow in the evolution of these IR-luminous galaxies. 5. Conclusions We presented the detection and characterization of massive outflows of hot molecular gas in three out of four nearby ULIRGs. We imaged the molecular outflows at sub-kpc resolution with VLT-SINFONI, using the H 1–0 S(1) 2.12 m line. We