We live in a wind tunnel. No really, the wind blows 3-4 days a week at 50+ mph all winter long at 9000 feet just a few scant miles from the Continental Divide in Colorado. That means, It's a cold wind that started at 14,000 feet and then hit our house like a freight train.
We installed a dryer vent last year that has been fantastic.
It's the HEARTLAND 21000 Dryer Vent Closure and we got it from amazon.com. It works like a dream. I no longer open my dryer on windy nights and wonder if I've opened the freezer. LOL! It hasn't seemed to impact drying times either. I know that the true mustachian way is to hang clothes, but I'm not there yet and may never be.
It also keeps the animals out. BONUS!
Here is the link:
http://www.amazon.com/HEARTLAND-21000-Dryer-Vent-Closure/dp/B00009W3I4/ref=sr_1_1?ie=UTF8&qid=1382672254&sr=8-1&keywords=dryer+vent
