Vent Fan - roof or side wall?

[GeorgiaWriter]

I'm planning a 4x8 squaredrop and considering placing my vent fan on a side wall instead of the roof. Doing so would give me a bit more room on the for a rack. Interior volume is only about 96 cubic feet, so I'm also planning a smaller vent fan. Any pros or cons to a side-mounted fan?

 

[Modstock]

I've seen a few Overlanding type trailers with that lil round vent/fan unit mounted on a wall.
The only con I see is, the roof will let out heat when needed and sometimes when the wind is just right it can blow cool air down during the hot night's .

On mine I had a extra 4" boat access port I unscrew and have a 4" round screen that I can pop in. One is for the wood stove and the other is at the top of my door. Extra ventilation and a nice place to photograph lightning during a storm.

You can get a metal lid also that is much more low profile and shatterproof.

 

[Tony Latham]

Teardrops need lots of ventilation.

90% of the time, we don't use the fan, but 100% of the time, we have the lid either fully open or just cracked if it's cold. Having the fan on the top of the cabin allows heat that's at the ceiling to convect out, which draws fresh air from the side windows.

Put it on top, and you won't regret it.

Tony

 

[working on it]

I've seen a few Overlanding type trailers with that lil round vent/fan unit mounted on a wall.
The only con I see is, the roof will let out heat when needed and sometimes when the wind is just right it can blow cool air down during the hot night's .

On mine I had a extra 4" boat access port I unscrew and have a 4" round screen that I can pop in. One is for the wood stove and the other is at the top of my door. Extra ventilation and a nice place to photograph lightning during a storm.

You can get a metal lid also that is much more low profile and shatterproof.

I built my 4x8 trailer to be safe & secure (almost armored) for my wife to use when she camped with her girlfriend's. Part of that included placing the awning-style windows high up on the sides, and using steel side vents. The side vents are rain-proof and have withstood contact with tree branches, something plastic vents wouldn't have survived. I put insect-proof screening inside three of them, so I can leave them open at all times, when the trailer is stored in my garage.

Here's a single post with links to other info on the vent system I use: Air Movement

 

[GeorgiaWriter]

I built my 4x8 trailer to be safe & secure (almost armored) for my wife to use when she camped with her girlfriend's. Part of that included placing the awning-style windows high up on the sides, and using steel side vents. The side vents are rain-proof and have withstood contact with tree branches, something plastic vents wouldn't have survived. I put insect-proof screening inside three of them, so I can leave them open at all times, when the trailer is stored in my garage.

Here's a single post with links to other info on the vent system I use: Air Movement

Interesting approach. Were those vents repurposed from something else?

NM - just read further and saw where your sourced them from.

 

[GeorgiaWriter]

I've seen a few Overlanding type trailers with that lil round vent/fan unit mounted on a wall.
The only con I see is, the roof will let out heat when needed and sometimes when the wind is just right it can blow cool air down during the hot night's .

On mine I had a extra 4" boat access port I unscrew and have a 4" round screen that I can pop in. One is for the wood stove and the other is at the top of my door. Extra ventilation and a nice place to photograph lightning during a storm.

You can get a metal lid also that is much more low profile and shatterproof.

Good idea about the boat port. I planned to use 4" dust system blast gates (Amazon.com: POWERTEC 70108 4 Inch Blast Gate for Dust Collector, Dust Collection Fittings : Tools & Home Improvement) for air intake, with 3d-printed insect screen inserts.

 

[GTS225-TNT]

I too, am using marine "deck plates" for windows and vent openings in the side walls. The beauty of them is that you can get semi-transparent centers that let in light. If your wall is thick enough, you could sandwich two of them, with screen in between. Put a clear center outside, and an opaque center inside, and you have a window that you can block for privacy. Unfortunately, it seems the largest you can get is 8".

I'm also considering installing a pair of 4-inchers, with modified centers, in order to hook up an external A/C unit.

Roger

 

[TimC-TNT]

I've built four teardrops. All with 12v case fans. These fans are for ventilation, not to provide a breeze on the occupants.

#1 was a small manifold above the foot board and exhausting through the bulkhead into the galley. Yeah, that was a mistake as I did not think I'd have the hatch closed at night resulting in no air movement so I had to add two small sidewall vents in the galley.

#2 my brother finished the build and put a case fan in the sidewall.

#3, my son's teardrop, we built a manifold in the footboard and it exits out the roof just behind the hatch hinge. That one works very well for ventilation.

#4, my latest, a 4x8, has a twin mattress and a cabinet along the road side wall. I built two case fans into the cabinet and they exhaust down through the floor. Of all the versions I like this the best.

 

[GeorgiaWriter]

I've built four teardrops. All with 12v case fans. These fans are for ventilation, not to provide a breeze on the occupants.

#1 was a small manifold above the foot board and exhausting through the bulkhead into the galley. Yeah, that was a mistake as I did not think I'd have the hatch closed at night resulting in no air movement so I had to add two small sidewall vents in the galley.

#2 my brother finished the build and put a case fan in the sidewall.

#3, my son's teardrop, we built a manifold in the footboard and it exits out the roof just behind the hatch hinge. That one works very well for ventilation.

#4, my latest, a 4x8, has a twin mattress and a cabinet along the road side wall. I built two case fans into the cabinet and they exhaust down through the floor. Of all the versions I like this the best.

Interesting to vent #4 through the floor. What did you use on the underside to keep water from coming up through it while driving?

 

[TimC-TNT]

The vent, mounted on the side cabinet, goes through the plywood floor and there is a screened baffle mounted to the underside and pointing about 14" to the rear. Toward the back of that baffle there are a couple short "steps" to keep any water working its way toward the spot where it enters the bottom of the floor and eventually into the cabinet space. Have had no problems with water intrusion. I did not install a door to block it off. The worst case is a spider or two might find the space desirable but I can clean it out easily. Little spiders can make it into the space. Spiders bigger than the 1/8" hardware cloth mesh would not make it into there.

The baffle is made of 1/2" XPS foam glued and screwed to the underside. It is mostly within the chassis frame and behind the axle so anything that would take it out would likely take out the axle first. If it ever gets torn off I can easily fix or replace it.

I also installed a side vent for make-up air for the cabin. I added a fly screen to that and it is on the opposite wall near my feet. I started out with out that vent but didn't like waking up to a cold shoulder from the door's window.

I know not many builders take this approach. Venting through a Maxxair or other manufactured fan or sidewall vents are the norm. I just wanted to avoid being forgetful while on a hike somewhere and the vent is open and it rains. An open ceiling vent might let enough rain in to ruin the trip. I know there are options for avoiding this but I chose to not invest in the Maxxair fan since I don't like the look or wind resistance of that big box on the roof. My tow vehicle is electric so avoiding any wind resistance is key. I know I'm missing out on the capacity of the Maxxair to move lots of air but I live in the north and rarely leave the area farther than the adjoining states. I don't spend the day in the cabin and it almost always cools off at night so that much air movement isn't a necessity.

BTW, installing a Maxxair or other fan will require make-up air. If that is provided by your door's window you may know what I was dealing with in the above description (cold shoulder). Anywho, there's many good ways to provide ventilation. Mine is just my preference.

 

[DrewsBrews]

Back when I was still going to build a squaredrop I wanted zero holes in the roof. I was planning use the rv side vent fans like this. Tuck them up on either side of the overhead cabinet with their own dedicated intake holes in the cabinet face. Then I wanted to put some static vents lower down on the side (more centered on the trailer) to provide baseline flow. Since the fan vents would not be covered there would likely always be a small amount of flow without the fans on. Which IMO is a good thing.

 

[philpom]

I would personally suggest putting the fan on the roof. As stated here already it can let the hot air out even when the fan is off and if it's hot inside you can run the fan and evacuate the hot air real fast. I have sliding windows that I can open a sliver on both sides but when it's freezing or in storage I added two 2" portals with screens built in on each side wall near our heads. They are permanently open. These allow the camper to breath while in storage and fresh air at night if the fan and windows are closed.

On high with the fan right above us I can create a very strong breeze through the camper.

 

[DrewsBrews]

High on the sides would still vent warm ceiling air. Just maybe not quite as efficiently as a direct roof opening.