does defrost mode affect mileage?

[nikvolkert]

i have noticed that the car runs significantly cooler when it is in the defrost/defog mode rather than the other settings. ( i usually don't even need to turn on the ac even on really warm days).
i just thought that the may be the possibility of the car automatically running the compressor part of the time or something like that.
if this is the case i imagine i should stop leaving it in the defrost/defog mode to save some mpgs.

[CTScott]

In that mode the compressor is automatically on (unless you do the DIY to unlink that mode from hitting the switch for AC), so you definitely burn more fuel when the knob is turned that way.

[STC]

^ Yeppers! :smile:

[BailOut]

To avoid the MPG hit but still enjoy some defrosting, simply keep the upper heater vents on and open one front window a bit. A sort of evaporation/sublimation occurs which clears off the windshield.

I have found that it takes a hand or two of opening to clear it but then just a few inches to maintain it.

[R2D2]

Thanks for the tip Brian!

[Bluevitz-rs]

I've noticed on my Echo that selecting the foot or lower vents only still sends air up to the windshield, so I never turn it to full defrost unless it's really humid out and the windows won't dry up.

Anyone notice this on the Yaris? I know this little cheat doesn't work on my parent's Matrix.

[yaris2010RS]

I've noticed on my Echo that selecting the foot or lower vents only still sends air up to the windshield, so I never turn it to full defrost unless it's really humid out and the windows won't dry up.

Anyone notice this on the Yaris? I know this little cheat doesn't work on my parent's Matrix.

i will definatly try that in the morning.....

[33OH]

I've noticed on my Echo that selecting the foot or lower vents only still sends air up to the windshield, so I never turn it to full defrost unless it's really humid out and the windows won't dry up.

Anyone notice this on the Yaris? I know this little cheat doesn't work on my parent's Matrix.

Yep, this works. I run the "foot" mode all of the time to defrost the windshield.

[yaris2010RS]

i tried mine and some air does go to the window but not alot...... i will try it next time i need the defogger and see if its an acceptable amount of air flow to defog/frost the window

[Bluevitz-rs]

yeah it isn't a tonne of air, but I've found that using the A/C to defog the windows, you have to keep using it or the moisture taken out by the A/C core gets sent back into the car the minute you turn it off.

[33OH]

Unless you leave it in fresh air mode.

[Bluevitz-rs]

Unless you leave it in fresh air mode.

No, regardless of using fresh or recirculated air.

[33OH]

Oh, I never have to move mine off of Fresh air + Foot even in the off position. It automatically defogs the windows for me. If I change it to re-circulated air, that's when the windows fog up.

Then again I do have a leaky car (water comes up through the floor), so maybe my constant fighting of fog is different than what we're talking about.

[Ryu]

I just tried the what so called " foot mode" and it works!! It does however send limited amount of air to windshield to clear up the fog, Is it best to to go for coldest air rather than hot air to clear up the fog on windshield faster?
Will the "foot mode" activate the air conditioning?

[Bluevitz-rs]

No foot mode does not. Only the two settings with defrost and defrost/foot. And go with warm air to defog the window. Once the windshield is warm, moisture won't condense on it anymore. Plus, warming cold air lowers the humidity level of the air itself, as cold air can not hold as much moisture as warm air can.

[Ryu]

No foot mode does not. Only the two settings with defrost and defrost/foot. And go with warm air to defog the window. Once the windshield is warm, moisture won't condense on it anymore. Plus, warming cold air lowers the humidity level of the air itself, as cold air can not hold as much moisture as warm air can.

Thanks Bluevitz-rs :thumbsup: