Pot lights.  Everyone loves them.  They are chic, minimalist and used frequently in both new construction and renovations.  Unfortunately they represent a penetration in the ceiling vapor barrier that when improperly air sealed can be a source of unwanted heat and moisture into the Attic space.  To properly air seal pot lights one must first install an I-C rated pot light, gasket-sealed tight to the ceiling drywall.  Then a poly boot should be installed over the light, preferably by an electrician who can properly fish electrical wires through the boot while installing the light itself.  Next the poly boot should be sealed with caulking to the ceiling vapor barrier.  The flanges of the poly boot may also be tape sealed for extra assurance of proper air seal, as in the photo below.  If these steps are followed to completion both contractor and homeowner can rest assured that this potential source of heat and moisture is mitigated, saving future headaches down the road.