Furnace wiring

I’ve run into a few cases where the wire from the beaker/fuse in the main panel to the furnace emergency shut off is solid aluminum wire. All the other circuits in the panel were copper. Is there a special allowance for this furnace wire to be aluminum (as a real estate agent claimed)

none that I am aware of I personally would ask to have it replaced and would ask the realtor what his qualifications were for making his claim

I was not aware aluminum is against code
if components connected to it are rated for it.

I had a new construction inspection last week. Solid aluminum wiring to the electric dryer. Sized correctly but based on our state language, I have no choice but to call for inspection by a licensed electrician.

I agree with you its not against code but how do we as home inspectors determine if a switch is or other component is rated for it. Would you call it up for further review?