My Newest Hypermiling Technique... CONFIRMED!!!
 

Breathe Through Your Nose!!!!!

Around winter time we all know that the less we use our vent heaters the quicker our car warms up to a greater fuel efficiency territory. In my case, with Pulse & Engine-Off Gliding, my car doesn't even hit normal operating temperature on my 14 mile morning commute. Thinsulate and added layers keeps my body warm but I still have issues with windows fogging up.

But now I added a new hypermiling technique that helps keep my window from fogging up as much by Breathing Through My Nose! I notice a significant amount of less water vapor comes out by exhaling through my nose instead of my mouth. Also when I exhale through my mouth the water vapor seems to head straight for the windshield immediately fogging it up. Exhaling through my nose directs it down and away from the windshield fogging it WAY LESS!

Now for a few questions: It seems that when its colder out it is natural instinct for me to breath through my mouth. Why is that? Also wouldn't breathing through my mouth make my body temperature colder? Kind of like the "Panting Dog Effect?" Therefore am I right with my thinking that breathing through my nose would keep more body-heat in?

The nose is meant to be something of a heat and moisture recovery device.

I just ban my passengers from breathing.

It's tough to enforce, but this can do the job:
https://www.grumpstump.com/squidoo/duct_tape.jpg

What about using a snorkel?

https://scubasteveforpresident.com/images/snorkel.jpg

^^ Can I route that to pass through my heater core? Then my 98.6* breath will help heat up the coolant. Any little bit helps!

Moist Air Intake, anyone?
https://www.gassavers.org/showthread.php?t=10026
:D

Do you really turn off your engine?

winkosmosis, lots of us turn off our engines. It's technically feasible with most manual transmission cars (but could damage most automatic transmissions). Some cars are better for it than others -- for example, cars with electric power steering or manual steering are better than cars with classic hydraulic power steering. For any given driver on any given route the decision must be evaluated individually.

You can search this site for the term 'EOC' (Engine-Off Coasting) to read more about it.

winkosmosis... out of all the things theholycow wrote, this is THE MOST IMPORTANT THING TO APPLY! The days where I have to be at work @ 6am I can easily apply this technique. But the days I'm at work @ 9am it's a little more of a challenge to apply this.

It's not the orifice, it's the angle. Your nose outlets are pointing down, the equally humidified expiration is directed downward into your lap not forward towards the cold glass.
The snorkel idea is a good one. Just make is about 5 feet long and use it exclusively for three minutes...