- Roof 25% faster
- Underground 15% faster
Sleeping on bed under roof/underground adds bonus 25%/15% to "Turns to sleep" timer.
To determine which bonus is applied, game check upwards from utility/bed to see if there's any wall or terrain block directly above.
If terrain block is found first, then it's underground.
If wall found (roof blocks counts as walls), then it's roofed, even if it's only one block hanging from scaffolding.