Are you defrosting the outside of the windshield or defogging the inside? If you're defrosting the outside, go out early and start her up. Crank the heat all the way up and put the vents on the windshield, recirculate the air for quicker defrosting. If you are combatting the windows from fogging from the inside, heat isn't the way to go. The reason they are fogging is because of the difference between the inside and outside temperatures. The windows will fog up just like a glass full of your favorite frosty beverage does on a hot day. Equalizing the temps between the inside and outside and gradually raising will guarantee the windows won't fog up. Get a set of side glass deflectors for when it rains. Does this help?