"winterizing" tips for the a/c

[Mercedes Fred]

Notwithstanding the weather in Texas or Florida, the approaching Fall means less and less a/c use. Anyone know of some good off-season preparations and procedures for a/c (on the 300e in particular); should one run the a/c once a month, even in sub zero weather, just to keep everything 'normal' etc? or alternatively, should one literally disconnect the ac in order to not even activate it accidentally during the off-season?

[jsmith]

most modern cars use the a/c to dehumidify air in the winter, otherwise your windshield & windows would fog up if you just blew warm wet air at it.

[engatwork]

Run it at least once/week and this should be accomplished whenever you operate in defroast mode.

[joel]

i have always wondered about the use of a/c to clear up
windows during the winter months.

what was changed? my old cars do not require a/c operation.

[jbaj007]

The airco air is dehumidified by the temp. drop. That's why many high end compressed air systems use a refrigerant dehumidifier as well as a dessicant (medical/dental systems come to mind). This dehumidified air defrosts by "drying" the glass because of it's lower relative humidity. Hot air works by raising the "dew point" of the glass above the temp. that moisture will condense, relative to it's % humidity. It makes sense if you say it really fast.

[joel]

gee, thanks! golden rule

[Robert W. Roe]

The old GM systems used to recommend running the AC once a week to keep the seals sealed, or something like that. I still try to do it at least once a week, just because it's cheap PM.