In this paper, we study how thermal haptic feedback can influence social interactions in virtual environments, with an emphasis on persuasion, focus, co-presence, and friendliness. Physical and social warmth have been repeatedly linked in psychological literature, which allows for speculations on the effect of thermal haptics on virtual social interactions. To that effect, we conducted a study on thermal feedback during simulated social interactions with a virtual agent. We tested three conditions: warm, cool, and neutral. Results showed that warm feedback positively influenced users' perception of the agent and significantly enhanced persuasion and thermal comfort. Multiple users reported the agent feeling less 'robotic' and more 'human' during the warm condition. Moreover, multiple studies have previously shown the potential of vibrotactile feedback for social interactions. A second study thus evaluated the combination of warmth and vibrations for social interactions. The study included the same protocol and three similar conditions: warmth, vibrations, and warm vibrations. Warmth was perceived as more friendly, while warm vibrations heightened the agent's virtual presence and persuasion. These results encourage the study of thermal haptics to support positive social interactions. Moreover, they suggest that some haptic feedback are more suited to certain types of social interactions and communication than others.