Originally Posted by Don Coyote
does a heated shield do much to keep the air around your face any warmer?
The answer is no, it will not contribute any measurable warmth inside the helmet. That being said, to keep your face warm you must minimize air flow inside the helmet as much as possible(read good sealing in the neck area). Unfortunately, now that you've stopped the air flow and your face is warm, your shield will start to fog. This is why you need
a heated shield.
Just noticed you are using a breath mask. These things are a must, and work unbelievebly well. Thought I needed some new ones so I went to nofogusa.com and low and behold, they have a heated version now: www.nofogusa.com/Optional%20Heat.htm