Help Appreciated: new member I just had a routine service call on a 5 year old Trane Furnance installed in our 2800 sq ft home. Tech says that our heating and cooling is grossly oversized for our home. Has a 120 BTU furnance and 5 T AC unit. He suggested replacing both units to the correct size and is working up an estimate on costs? Do not have specifics today, but can get them. This just occurred yesterday 2/8/10. System is working but had issues in Dec with High Limit Switch trips when weather got cold. Mike posted that downsizing burner/etc would be a cheaper fix than a complete system changeout.???