If “Make Capacity Count” was enacted, this proposal does nothing. Otherwise:

Create a subrule of Location called Over Capacity with the text:

Whenever a Location has more villagers in it than its capacity, it is said to be Over Capacity.

If an Indoors Location is Over Capacity and it has at least one Route to an Outside Location, or has no Routes, it is considered to be Draughty for as long as it is Over Capacity, as is every Indoors Location that is directly or indirectly connected to through only Indoors Routes (where an Indoors Route is defined as any Route that is from an Indoors Location to an Indoors Location).

If an Indoors Location is Over Capacity and it has no Routes to Outside Locations but at least one Route to an Indoors Location, then for as long as it is Over Capacity, the number of Villagers by which it exceeds its capacity is added to the number of villagers in each Indoors Location it has a Route to for the purposes of working out if that Location is Over Capacity.

Replace the line “When a Villager’s Location is Outside, they lose 0.1 Heat for each unit of their Time that is spent.” in Location with

When a Villager’s Location is Outside or is Draughty, they lose 0.1 Heat for each unit of their Time that is spent.