1) Fogging occurs when warm, moist air inside the car hits the cold air outside your windshield. Your snowy boots, wet gloves and even that cup of steaming coffee, as well as your breathing create moisture in your car. Lower the moisture level by keeping as much of that snow and water outside your vehicle. Cover your seats and trunk/boot area with a large dry blanket each time you enter your car in the morning.
2) Make sure that you are taking in fresh air from the outside of the car (if it’s snowing, clear the outside vents before pulling out of the driveway) by turning the recirculate button off. If you are recirculating air you are simply recirculating your own breath. This means that moisture never leaves the cabin and de-fogging the windows becomes very difficult, if not impossible.
NO AC, heater doesn't really work.
3) Lowering your windows to equalize temperature and dry out the cabin usually isn’t necessary, unless you have an extraordinary amount of moisture in the car. Toss on your heavy jacket and drive with your windows partially down.
For harsh winter conditions, you might want to consider buying a car with working automatic climate controls. This system not only maintains a consistent temperature, but also monitors and controls moisture levels, so that windows never fog up. This feature is commonly found on new cars, but is not always standard.
