The picture shows heat escaping from the house through the can lights.

Whether the cans are on or not doesnt

really matter, the heat is getting through enough to melt frost on the

roof. One builder I know refuses to install can lights in this setting, claiming he has no way of insulating above or around the fixtures. None of the audit software I have will adress this in a simulation, so I cant tell you what it costs extra to heat this house. But I am confident it is significant.