Tell me it isnt so!! Ohhh if you were here in the humidity today in the south...
Anyway, my Coleman has an apx 14" opening just like the vent fans. So you should havent any problem. Pull the interior cover and let it drop down and you will see the actual mount. Also, if still in doubt, look your particular model up online and you should be able to find a manual that will tell you the necessary opening for it then you will know for sure. The model # shouldnt be hard to find on your unit. Pull the filter cover......