bath fan duct

[mf915]

There are 3 types of metal sheets (that you roll into duct) available at Home Depot

1) very thin aluminum
2) galvanized
3) thicker galvanized

I chose #2. But then the Home Depot guy said I should have chosen #1. He said aluminum does not rust, galvanized duct will RUST...

Is that true ???

[leejosepho]

Yes, steel can eventually rust when the galvanized treatment on its surface is somehow compromised. Hence, and especially in a damp application, the aluminum duct will outlast the galvanized-steel duct. Steel is better in a high-temperature application such as the venting for a gas furnace or water heater, but aluminum is preferable for damp applications such as dryer and bathroom vents.