My brachys seem to do pretty well in ambient temps in my Chicago apartment. They do like the air movement provided by my not-tight windows but the temps go down to high 40sF/low 50sF right in the windows in winter and as long as I keep them pretty dry, letting them dry out between waterings, they seem happy through the winter (not much growth, but hey, they're resting?) and the summer surge is noticeable. I do keep them watered plentifully all summer, until about Halloween. Would like to try P. thaianum and wonder if it's somehow very different? Your pot of them is utterly stunning.