As a practical matter, here in the south in the winter we can have temps
in the 40's, 50's and 60's with rain and very high humidity. The heat
from the defroster blower is not sufficient to defeat that high
humidity. With the AC turned on, the air dries out, helping the
Defrosting blower be more efficient in dissipating the windshield fog
that forms in that particular environment.  With an OAT below freezing -
what's the point in running the AC. The air is going to be to dry to
hold fog forming water droplets anyway,

John
On 10/4/2012 9:58 AM, mcneely4@cox.net wrote:
> I know we are told this.  But what happens when you turn the AC on when the temperature is way down below freezing, which it is in some places most or all of the time in the winter?  Won't the compressor pound itself to death?  We don't turn on home AC in winter to save seals.  We keep it off to protect the compressor from destroying itself.  Just wonderin'.  I generally do try to run automobile AC occasionally in winter when it is warm enough that I think the compressor can manage, as advised.  But I have had automobiles go all winter without running the AC.  It still works on my Honda, no bad seals, and the thing is now 15 years old with 200k miles.  Since the AC on my camper has been rebuilt, I can't say that it has had no bad seals.  It probably did, but I can't see how one can run the AC when the outside temperature is down around 0 F, or even 30 F, without beating up the compressor.
>
>   McNeely