Before I bought my ProClip mount I used a vent mount. I live in Phoenix, AZ so cold air out my vents is important here too. I never noticed a problem with air flow when my phone was in the vent mount. In fact, I really liked the cold air blowing on my phone to keep it cool when running navigation apps. The problem with the vent mount was that there were times when I wanted heat instead of cold air out my vents. This happened when I drove to visit my in-laws who live in a very cold location. The heat blowing out the vents made the phone way too hot. Most of the time I am blowing cold air out my vents, and it has never been a problem having my phone in a vent mount, but the few time I did need heat out the vents it was terrible having the phone in a vent mount. That is ultimately what turned me to the ProClip mount because it keeps the phone out of the windshield and away from my vents.
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