Somewhat disappointed

[supmet]

Originally Posted by YarisOwnersDad

When I tried to go get out of defrost mode, the windows would immediately fog.

I hope you realize if you never had the A/C on in the first place they wouldn't fog, and if you left the A/C off for more than 2 minutes it would take care of itself...

User created self sustaining problems ftw.

[YarisOwnersDad]

Originally Posted by supmet

I hope you realize if you never had the A/C on in the first place they wouldn't fog, and if you left the A/C off for more than 2 minutes it would take care of itself...

User created self sustaining problems ftw.

Not so sure about that. Have you ever experienced the extremely high humidity of the Midwest? It SUCKS. The dew point is much higher around here than what you are accustomed to, I'm sure, since your sig says you are in southern CA.

It was in the very early hours of the morning, while the outside temperatures were still in the low to mid 60s, when I was using the defrost mode.

Tom

[supmet]

Originally Posted by YarisOwnersDad

Not so sure about that. Have you ever experienced the extremely high humidity of the Midwest? It SUCKS. The dew point is much higher around here than what you are accustomed to, I'm sure, since your sig says you are in southern CA.

It was in the very early hours of the morning, while the outside temperatures were still in the low to mid 60s, when I was using the defrost mode.

Tom

I've lived in wisconsin, and my mom lives in chicago. Dew point/humidity is only really an issue because you are creating a difference in temperature between the water molecules in the air and your windshield.

edit: I've pretty much driven the gamut of humidities, from death valley and vegas to the midwest. The A/C has never been "required" to keep the windshield from fogging. You're making a cold windshield with the A/C, which INCREASES condensation. Having a windshield the same temp as the outside air creates the least amount of condensation, regardless of humidity.

[YarisOwnersDad]

Originally Posted by supmet

I've lived in wisconsin, and my mom lives in chicago. Dew point/humidity is only really an issue because you are creating a difference in temperature between the water molecules in the air and your windshield.

edit: I've pretty much driven the gamut of humidities, from death valley and vegas to the midwest. The A/C has never been "required" to keep the windshield from fogging. You're making a cold windshield with the A/C, which INCREASES condensation. Having a windshield the same temp as the outside air creates the least amount of condensation, regardless of humidity.

Sup:

I think I caused all of this confusion by the way I worded the post when I said the A/C was on all the time. When the defroster is on, the A/C compressor is being used, so I count that the same as using the A/C as far as the effect on MPG.

We both know that condensation occurs when the glass is at a temperature lower than the dew point of the air in contact with it. From the way I worded my post, you apparently thought that the reason the glass was colder than the dew point temperature of the air in the cabin was because I had been using the A/C. That was not the case. The glass temperature was just naturally cold because of the outside temperature. This was before sunrise, and the outside air was probably in the low to mid 60s.

Tomster

[b_hickman11]

Originally Posted by supmet

I've lived in wisconsin, and my mom lives in chicago. Dew point/humidity is only really an issue because you are creating a difference in temperature between the water molecules in the air and your windshield.

edit: I've pretty much driven the gamut of humidities, from death valley and vegas to the midwest. The A/C has never been "required" to keep the windshield from fogging. You're making a cold windshield with the A/C, which INCREASES condensation. Having a windshield the same temp as the outside air creates the least amount of condensation, regardless of humidity.

I can you never been to Texas. With 100% humidity the windows will fog up from your breath. So it's not always caused by just using the ac.