> Air seal and upgrading insulation: correct me if I'm wrong, but that implies either tearing open all of the exterior walls or ripping off all of the siding, n

> Air seal and upgrading insulation: correct me if I'm wrong, but that implies either tearing open all of the exterior walls or ripping off all of the siding, no? If you do the exterior walls yes, but most heat loss is through the attic and roof. Air sealing and super- insulating the attic floor is pretty cost effective. Likewise sealing cracks around windows and doors.