90% efficent furnace requires new ducts?
My first post, your thoughts welcome.
My mother in S. Cal. recently had her gas furnace replaced with a 90% efficient unit. The county inspector told her that since it is a 90% unit vs and 80% unit, the ducting also needs to be inspected by another inspector in order to get a final at additional expense.
The installer said that while on the books for a while, the county just started inforcing this requirement. He also said her ducting (the flexible insulated variety) in the attic is too brittle and will need to be replaced for another $2500. I can understand the plastic around the fiberglass getting brittle but so what! Anyway the furnace is delivering heat to the house just fine with the existing ducting.
Can anyone shed some light on this and why it would be necessary for a 90% furnace and not an 80% unit.
I’m quite sure the manufacturer doesn’t account for the additional potentia expense in inspections and duct replacement in their payback equations for the additional efficiency.
Is it even worth getting a final since the furnace has is fine?
I’m confident the installer is not scamming her.
Thanks for your input.