The tearoom has 2 seasons...summer (when we use a brazier to boil water) and winter (when we use a sunken hearth to boil water). Switching between the seasons is fairly simple. Tatami mats are exchanged so that the sunken hearth can be revealed and used.
https://files.mastodon.social/media_attachments/files/113/444/753/681/532/668/original/92cec1f0a80b7a92.jpeg