Originally Posted by TWP723
In my opinion, the II's aren't worth the extra $$. Both do the exact same thing. The manufacturer makes it sound like they're sooo much better than the regular cover. When it comes down to it, air is entering the same size hole into the TT. I just don't see spending the extra money when it can be used for other things. Like beer.
The purpose of a MaxAir vent "cover" is to allow you to keep vent cap open when it rains. The air flow thru an opening dependent on several things and resistance is one. Without a vent cover you would be correct, only so much air is going to be vented based on outside wind and inside venting caused when you open windows to let air flow in or out. The issue with needing the Maxair II is based on if you want to add a fantastic or similar fan to the vent opening. Try blowing thru a straw and then do the same thing thru a 1" piece of pvc of the same length. The bigger opening allows air to be moved easier thru the bigger pipe when you try to blow into them. The fantastic fan is trying to push air out or pull it in and the size of the vent opening in the vent cover WILL impact the amount of the air it can move. The fan will have to push harder if you install the regular vent cover and that can lead to early failure of the fan.
No vent cover [just the vent cap] and a certain amount of air will flow. At a hi flow fan with no vent cover and you'll get soaked at night if it rains. Use the smaller cover and you risk failure of the fan motor and will restrict the air flow.