Loss of heat?

[Le Chat]

When I open my front door when it is cold and frosty outside, does the cold air come into my house, or is the heat from the house sucked out into the cold air outside ....or both?

[Clanad]

Heat transfer or heat flow always moves warm (air) to cold. The greater the temperature differential, the greater the rate of flow or transfer...

[chakka35]

Both, is the answer. The warm air from inside, when it meets the outside cold air, rises towards your front bedroom window. Cold air then comes into the house underneath that outward flow.
You can feel the cold air coming in. Someone standing outside would feel the warm air coming out.

[Space]

cold air comes in
and warm air comes out