Bug: Heaters will not raise the temperature in caves you have built a roof over.

[MFWIC]

What the title says.

Items in a stockpile inside the roofed over cave also seem to stay flagged as "outdoors", though they don't seem to decay.

[mlzovozlm]

:| simply because you dont enclose it up with door or wall, its viewed as the "Same room"with the "outdoor", thus "outdoor"+no heating up, this is no bug

[5thHorseman]

Click the room stats tool in the bottom right corner and then hover over your room. In addition to telling you things about it, it will highlight the borders of the room if it's truly a room. I suspect @mlzovozlm is correct and your "room" is actually still open to the outdoors through a wall.

[Tynan]

As 5th said.

If it is indeed enclosed, please post a savegame or screenshot of the whole area in a new thread. Thanks for reporting.

EDIT: Looks like it may indeed be real, possibly related to overlarge underground spaces. I've requested the savegame.

[Tynan]

Apparently this was caused by mods (Embrasures).