In alt.home.repair, on Wed, 29 Jan 2020 20:57:34 -0500, micky
wrote:

Do electric roof fans rust enough that they must be replaced?

My fan, in the pitched part of the roof, looks like new from the inside.
The plastic top, the metal screen**, and the metal frame below the
screen. all look perfect.

**Not wire screening but sheet metal with a lot of holes in it.

But the roofer who came yesterday wants to replace it, because he says,
it's rusting.

He also says the new one will be better, new thermostat, new humidistat.

My current thermostat works fine, I never take steamy showers or baths
so I don't need a humidistat.

I do believe there is some rust (maybe at the outer edge of the frame)
and around the holes where I nailed the fan to the plywood 35 years ago.
But I doubt if there is much and new nails can be put in an inch away
from the old nails, where I'm sure there is no rust at all. Will take 3
minutes.

So is there any reason to replace the fan?

My fault. I shouldn't have used the word "any".

So let me rephrase the question. Given that the fan has served me well
and I intend to continue to have one, is the rust he reports a good
reason to replace the fan.

Given that the fan looks like new from the inside, I cant imagine there
is enough rust one the outside to prevent the fan from being nailed
firmly in place, even the current nail holes have gotten bigger.