Smart Home Heating Technologies (SHHT) have been designed to improve demand flexibility and energy conservation. SHHT rely on rational theories of energy use postulating that people will use less energy when the energy cost is higher. The inclusion of AI within SHHT is poised to optimise energy use in the future as the introduction of lower carbon energy sources place new demands on the grid. When SHHT is introduced in the home, however, they become situated in temporal heating practices that are shaped by an interplay of materiality, meanings, and competencies. We report findings from a mixed methods field study involving eleven households utilising an AI-enabled SHHT probe ‘Squid’. Taking a temporal focus throughout, our study contributes a new lens as to why households may not fully engage with SHHT's rational design, given that energy conversation is already embedded in their ongoing socio-material practices with heating. Focusing on the AI-human relation, we articulate the necessity for human agency where heating is involved, whilst also advancing an understanding of the new forms of hidden labour that households incur before they can engage with the AI. Crucially, our research informs the ongoing HCI concern over how humans understand AI, raising the question of who is responsible to assess the appropriateness of AI when the effects of human-AI performance remain opaque. Our findings contribute a new theoretical perspective into the intricate relationship between individuals and AI in the home and raise several new design implications for SHHT.