As the cold weather is approaching, I have been hunting for a solution to the problem I had last year of foggy glasses and goggles. I was reluctant to pay $90+ for goggles that MAY limit fogging and I did not want any exposed skin either (as it freezes). So I came up with this idea.
I took the goggles I used last year ($50 from sport check - smith goggles) and opened up some holes on the top foam vents. The foam vents simply did not allow enough air in, so I opened up them.
Secondly, as I exhale through the mouth, I did not want the warm air entering my goggles via the bottom foam vents, so I added a layer of weather stripping below (essentially a thicker layer of foam).
I also made the nose holes on my balaclava slightly larger (I have a bigger nose than most) and voila... it works.
In a standing position, I fog up. However, on the bike, with the head tilted forward, air enters the top vents and neither do my goggle or glasses fog up. I took it for a spin and I was trying to fog them up and I could not. At one point, I was able to get a little bit of fog..and it vanished quickly.
See pics below.
weather stripping on bottom vents