Is air infiltration a type of convective heat transfer (convection) I have a building / physics question...
A major source of heat loss in homes and buildings is infiltration through cracks (warm air from inside seeping out). Wondering if this falls in the category of convection as a mode of heat transfer?
 A: My guess, if the source of heat is in the centre of the room, is a mixture of radiation directly to the walls, plus convection of the air to the walls. 
When the heat gets to the walls, it's conduction through the walls, unless there are holes, cracks or vents in the walls, when it's convection of air through the walls.
Warm air moves outwards, from the room to the outside, so maybe  I would not use the word infiltration in this question.
A: 
Wondering if this falls in the category of convection as a mode of heat transfer?

Yes.
You are discussing heat transfer due to air traveling through a crack in a wall.  Any heat transfer due to a moving fluid is convective heat transfer.  
If there is wind, then it is further categorized as forced convection.  If there is no wind, just bouyancy effects due to different gas densities, then it is called natural convection.
For home heating/cooling, conductive and radiative heat transfer will also contribute.  The relative importance of convective heat transfer through cracks in the walls depends on the construction.  Houses with double-walled construction will have less air leakage than house with single-wall construction.
