# Roof Vents Open With The A/c On



## joeymac (Aug 19, 2010)

Question ? I have a 312BH. Last spring I installed the Vortex Replacement fans on the two ceiling vents. One in the kitchen area and the other in the bathroom. 
I don't usually keep the ceiling vent in the kitchen open while we are camping, unless we are cooking something in the kitchen...It helps take the hot air and smoke out of the camper. 
The bathroom vent is another story...That usually is always open with the fan running and the bathroom door closed, no matter if it is occupied or not. 
My question is this....Does keeping the bathroom ceiling vent open all of the time with the Vortex fan running affect the performance of the A/C unit ????? We are struggling to keep the camper cool on the 90+ degree days....We even have the windows covered with the reflective silver insulation, helping to keep it cooler. Anyways, looking forward to the advice I receive. 
Thanks in advance !
JM


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## W.E.BGood (Jan 15, 2011)

I am not particularly familiar with your model, but I'm going to hazard a guess it's like most other TT's in that the cooling is a closed system in that it conditions and recirculates the air inside the trailer. Leaving an opening to the outside only sends the cool/conditioned air outside where you lose it.
If I'm wrong on this I'd like to hear from others.

Regards, BGood


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## cdawrld (Jul 31, 2011)

With the roof fan running (outward)your creating a low pressure zone in the bathroom. Outside (hot) air will come in every nook and cranny through out the trailer, to equalize the pressure.
Also since cold air sinks. The 2" gap on the bottom of the bathroom door is drawing the cold air into the low pressured bathroom and out the vent.


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## RDS (Jul 20, 2011)

We keep the bathroom vent cracked, but only turn the fan on if someone is using the bathroom. This has worked well on hot days.

Remember whenever you have a roof fan on you need a window or vent open somewhere else to keep from creating negative pressure inside the camper.


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## hoodscoop (Mar 29, 2012)

All exhaust fans are rated via cubic feet per minute (CFM's). Of course a cubic foot is a box 12"x12"x12". If your fan is rated at 50 CFM's you are removing 50 of these boxes per minute!, that's a lot of air, again _*per minute*_. When you remove air, it must be replaced, and it will get that replacement air from the easiest place it can, likely from within the camper. Keep all openings closed and open only when needed and for only as long as necessary. Good luck.


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## mmblantz (Jul 1, 2007)

I have a Vortex in my bathroom as well. You can feel the airflow on your legs that it creates coming under the door.....that's your A/C going out the roof vent. Turn it off unless you need it. You can proly get away with leaving the vent open as long as you shut the the door but it would be better to shut venthatch as well. ---Mike


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## Jewellfamily (Sep 25, 2010)

I'm guessing your going to have trouble keeping it cool like this. The 312's are already notorious for barely being able to keep them cool without the air change rate that you are adding to the equation.


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## joeymac (Aug 19, 2010)

Jewellfamily said:


> I'm guessing your going to have trouble keeping it cool like this. The 312's are already notorious for barely being able to keep them cool without the air change rate that you are adding to the equation.


Took everyone's advice and kept the roof vents closed and the fan in the bathroom off until needed. Seemed to work much better this way. 
Although in 100+ degree heat it was difficult to find a cool place to hide.


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## Bill & Kate (Apr 28, 2012)

We keep the fans off unless there is a need to exhaust air while cooking or while using the bathroom. We do leave the vents partially open with the theory that the hottest air is rising to the ceiling, and can find it's way out through the vent. In practice, it doesn't seem to make much difference - if we can get the inside 15 degrees colder than the outside and reduce the humidiy, we are doing good. And the hotter it gets, the harder it is to get the 15 degrees ....


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## sunnybrook29 (Oct 7, 2009)

When climbing in the cab of a hot pickup truck I will turn on the dash air and lower my side window a couple of inches for the first 5 minutes or so . This cools the cab quicker as the rising hot air goes out the window . Would this practice work in the T T ? Maybe draw hot air out for the first 5 minutes or so ?


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