It breaks down in a week, and it's not clear there's a start trigger rather than heat release beginning immediately after manufacturing. This isn't going to replace blankets any time soon. Hot water bottles, maybe, if it can be made inexpensively enough and has a stable storage state (or can be produced quickly on site). I'm sure Maryam will attempt to simplify production, given that Farasat's new bed needs a weekly refill, but making it affordable for the poor rather than a luxury for a steamsmith's exotic pet ...