Responded to customer concern regarding furnace exhaust smell and respiratory issues. Performed comprehensive inspection of 20-year-old furnace including heat exchanger examination (no cracks or holes found), exhaust venting verification, and filter system check. Identified large floor opening beneath furnace allowing significant cold air infiltration, likely drawing in external diesel exhaust temporarily. Noted minor water leakage on one pipe, but no significant defects requiring shutdown. Provided bath replacement estimate per customer request.
