I am in Northern NJ and the previous owner put the HVAC (gas Trane XR80 heat and A/C) in the attic. I am trying to figure out what is the "proper" way to look at the attic now. I understand traditionally you would simply insulate the attic floors with as much insulation as possible and let the attic get hot or cold. BUT... First of all we have a full walk up attic with regular staircase and door leading up to the attic, and a subfloor on the attic joists (not exposed joists). Second of all, with the HVAC setup up there, don't we want to keep it as cool as possible in the summer, and as warm as possible in the winter? Duct work is insulated with standard R6 insulation (flex duct). I am not sure how feasible it would be insulate the duct worth further. On the joists of the attic floor is very old insulation from 1950?, unknown R value. Again remember we have flooring in the attic, so this insulation is not accessible. On the walls/raftes we've got R13 and R11 respectively. We have an attic vent fan that goes on at 110F in the summer. I crack the windows on either side of the attic in the summer. Not sure if I should cover this attic ceiling vent holeup in the winter, and/or close the windows in the winter. The issue is that the attic is sort of half conditioned, half not. With the HVAC up there, I would think it's important to keep the temperatures relatively close to living conditions otherwise the HVAC is going to be negatively affected? Finally I do not want to do anything too drastic, as I'd like to keep the option of finishing the attic... So should I focus on insulating the attic rafters/walls more, or???? Close the windows in the winter? Someone suggested I should be concerned about moisture in the attic. This does not seem to be an issue that I can see at least. Is it possible that the furnace keeps it dry? What about leaving cracks for the 60k BTU burner to get oxygen?