Changelog

1.0.1

Warning: Do not use on a server until the mod is fixed. Mixed sessions (not every player installed) desync flames vs fuel, and unmodded players can still get local comfort/heat from a paused fire.
README lists this in red at the top.

Requires Valheim 1.0 (Unity 6) and BepInEx Pack for Valheim 5.4.2350+.
First release: pauses fueled Fireplace pieces when they are not needed and keeps remaining fuel.
Fires (campfire, iron fire pit, hearth, bonfire) pause when no player is within 10 m (configurable). They still burn in daytime while you cook.
Lights (sconces, standing torches, colored/wisp torches, braziers, jack-o-turnip, lava lantern) pause unless someone is in range and the space has no usable daylight.
Windowed halls in full sun stay off even with a player standing there. Sealed pits only light while someone is nearby, day or night.
Alt+E pins a piece to Always burn (vanilla fuel use) or back to Managed. Hover text shows the mode and pause reason.
Fuel catch-up after an unloaded zone is skipped so walking back in does not dump a huge fuel bill.
Client-side. Dedicated server is not required. Every player who joins should install it. Stay-lit mods conflict; DaylightSavings runs last on Fireplace.IsBurning.