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roof vent with or without fan?

PostPosted: Mon Mar 12, 2018 12:04 pm
by camperRN
I am trying to build on a budget and looking at roof vents there are vents with fans for $100+ but the standard vents are under $20. I plan on having AC for hot weather so can anyone give me a reason why I should buy a roof vent with a built in fan? I'm also thinking that I could build some sort of bracket to hold a small fan on the vent if its something that is really needed.

Re: roof vent with or without fan?

PostPosted: Mon Mar 12, 2018 4:03 pm
by tony.latham
camperRN wrote:I am trying to build on a budget and looking at roof vents there are vents with fans for $100+ but the standard vents are under $20. I plan on having AC for hot weather so can anyone give me a reason why I should buy a roof vent with a built in fan? I'm also thinking that I could build some sort of bracket to hold a small fan on the vent if its something that is really needed.


Well... we boondock and don't have an air conditioner so keep this response in that context.

But if I told my wife I was going to build a new 'drop and was leaving out the fan, she'd think my cheese had slipped. In 2004 I bought a commercially built 4'-wide teardrop that didn't have a fan. In the summer of 2013 we came across a 5'-wide with a fan and took the tour from the proud owner. I kept glancing at the fan. Two weeks later I was building a new 5'-wide teardrop and for sure we put a fan in it.

Image

Here's what I would suggest: Buy the $20, 14" vent and run a pair of 12V wires to it. Down the road, if you start wishing--and I think you will--pull the vent and install a fan.

And make sure you have two screened windows.

:thinking:

Tony

Re: roof vent with or without fan?

PostPosted: Mon Mar 12, 2018 8:54 pm
by camperRN
Sounds reasonable.

Re: roof vent with or without fan?

PostPosted: Tue Mar 13, 2018 4:36 pm
by ae6black
I don't have 12 volt in my tear, just 120 volt for shore power. I built mine almost exclusively for cold weather. After having the camper for a few years, I decided that I also like to camp and use this tear as a spare bedroom in relative's driveways. During July and August in Pa that is a problem. It's just too darn hot. Plus now that my Brittany camps with me. (a fifty pound dog can add a surprising amount of heat in a small space as well) Simple solution was to just buy a cheap walmart 9 inch square fan and tie it up to my roof vent which is just a simple non powered vent. It works pretty well but isn't all that sightly. But that said, after sweating through a night or two (it's amazing how hot a tear can get without a cool breeze coming through on one of those dead still nights, I decided to hack a hole through my galley and mount a 5000 btu ac when I found them on sale. Haven't used it yet but suspect I won't have any issue keeping cool as long as I have shore power. Since I didn't want to mess with the hose method at this point, I'll have to leave my galley hatch open at night when I am using the AC. During cold weather when my unit gets used the most, I'll simply pull the AC out and mount a cover over the hole. What I have thought of doing should I ever desire to build Tear # 2 and not go the normal route of adding a 12 volt system, would be to add at least another non powered vent on the roof. There would be plenty of room and plenty of structural integrity to mount two vents side by side. I was thinking of about a foot space between the two vents would be ideal for my situation. If I went with a rain drop style cabin, it could even be a possibility to put an extra non powered vent forward. I think I've used my TD for about five years now in all kinds of situations. I've only had wind driven rain being a problem once and had water come though my vent that was cracked a few inches. I just tied a cake pan to the little eye bolts that I hung around my vent for hanging that walmart fan and for drying wet wash towels while i was driving back home after the trip to catch the dripping water. In my application, that vent is at least cracked every time I am in the tear. I've always been surprised how much breeze comes through these roof vents. With the roof vent cracked and the side window open, there's plenty of air circulating to keep from CO2 poisoning. I think the real point is what do you want to do with your unit? Maybe a non powered vent would work. Personally, I can sleep better with that square 9 in walmart fan buzzing above me in my tear than I can stand the fantastic fan that I have in my full size camper running all night in the bathroom.

Art

Re: roof vent with or without fan?

PostPosted: Tue Mar 13, 2018 5:24 pm
by Woodbutcher
When people ask what is the most important thing no build should be without, I say a Fantastic Fan. There is no substitute for the ability to move air quickly on a warm evening.

Re: roof vent with or without fan?

PostPosted: Wed Mar 14, 2018 12:35 pm
by working on it
Woodbutcher wrote:When people ask what is the most important thing no build should be without, I say a Fantastic Fan. There is no substitute for the ability to move air quickly on a warm evening.
  • I circulate plenty of fresh air, without a roof vent, and without the possibility of leaks or damage to the vent, and with a lower roofline, by mounting sturdy steel vents on the sidewalls. The combination of the steel , waterproof vents (with computer case fans helping airflow) and a strong main fan inside the cabin, provide as much air circulation one mght need, in any weather conditions. The awning-style windows help out, too, when open, even in the rain.
  • I built my TTT for strength, durability, and weather resistance, with no exterior feature vulnerable to the elements. Especially on the roof. I've been in trailers that had roof leaks: from either the overhead A/C unit, a torn rubber roof, or (most frequently) from a roof vent; that ruined the interior. I just recently had to replace the damaged/deteriorated plastic cover on my 20ft trailer's vent (which had cracked, and was leaking), before I stayed in it, while my new house project was underway. It was replaced before any water damage had occurred (soaked up by the wool vent insulator, and didn't get past it), fortunately, but it reinforced my view that overhead vents were prone to damage & leaks, over time.
  • I wanted waterproof vents, preferably not installed in a vulnerable spot (less chance for damage? tree limbs, hail, meteorites?), like the roof, and made of steel, not plastic.. Having run a shipping/receiving dock for years, I saw enclosed trailers with all types of venting, and wanted to emulate that in my build (also an automotive-type piece, which I was leaning towards as a sub-motif). I narrowed the choice down to two "enclosed trailer vents", normally roof-mounted, but would serve even better mounted on the sides. Here's a comparison of the two "finalists" I chose between: http://www.etrailer.com/comparison.aspx?pc=RV-626-062&pc2=9139 Primary usages are to admit insect-free ambient air, and expel humid stale air. Computer case fans are mounted behind them, to make them more efficient, at a low power cost. The vents were to be sealable, waterproof, screened, and rust-resistant. I chose the Redline 9139 (also partly because it looks like a drive-in speaker!- liked the retro look), and it has a butterfly closure for tunability.
  • In hot weather, the interior is cooled by A/C, in moderate weather by a 11" fan (and two awning-style windows), and in cold weather, by one or two 200 watt heaters. Small computer case fans circulate minimal airflow thru the upper wall vents at all times, reducing humidity build-up inside. A high-flow fan (a Honeywell 11", under the front overhead shelf) uses variable fan speeds and angles to circulate the interior air.http://www.tnttt.com/viewtopic.php?f=42&t=69753
  • vent 9139 used for three purposes.JPG
    vent 9139 used for three purposes.JPG (244.86 KiB) Viewed 2338 times
  • wall vents, 11 inch fan, and airconditioner work together OK.JPG
    wall vents, 11 inch fan, and airconditioner work together OK.JPG (202.93 KiB) Viewed 2338 times

Re: roof vent with or without fan?

PostPosted: Wed Mar 14, 2018 3:18 pm
by NotJammer
Yes, you will want a good power reversible roof fan.

Fantastic fan is the best. Not free. I installed one in an Avion 25 years ago.

My new fancy trailer came with a cheap vent with no fan.

An hour online, I found mine was made by Heng, which makes a lot of RV parts. Indiana made.

Heng is available on Amazon. You can buy just a Heng vent for very little now.

Later upgrade to their Heng upgrade, which I have bought but not yet installed.

Don't buy a Heng or anybody's fan with the tiny fan. Those are junk and move no air.

Re: roof vent with or without fan?

PostPosted: Thu Mar 15, 2018 6:14 am
by absolutsnwbrdr
Woodbutcher wrote:When people ask what is the most important thing no build should be without, I say a Fantastic Fan. There is no substitute for the ability to move air quickly on a warm evening.


I second this 10000x. On a hot & humid summer day you want to be able to get that air flowing, and since heat rises the best place to remove it is from the roof. I've put a fantastic fan in all my builds (even the convertibles), and will continue to do so. A properly installed roof fan (its not rocket science) will not leak, and you'll never question why you spent the money to do it, and do it right. Aesthetically, the roof fan is also fairly discrete and out of the way. If the time ever comes to sell your camper, the new owners will be happy to see a fan already installed.

Re: roof vent with or without fan?

PostPosted: Thu Mar 15, 2018 10:27 am
by tony.latham
absolutsnwbrdr wrote:
Woodbutcher wrote:When people ask what is the most important thing no build should be without, I say a Fantastic Fan. There is no substitute for the ability to move air quickly on a warm evening.


I second this 10000x. On a hot & humid summer day you want to be able to get that air flowing, and since heat rises the best place to remove it is from the roof. I've put a fantastic fan in all my builds (even the convertibles), and will continue to do so. A properly installed roof fan (its not rocket science) will not leak, and you'll never question why you spent the money to do it, and do it right. Aesthetically, the roof fan is also fairly discrete and out of the way. If the time ever comes to sell your camper, the new owners will be happy to see a fan already installed.


Bingo. :thumbsup:

Image

Tony

Re: roof vent with or without fan?

PostPosted: Thu Mar 15, 2018 7:18 pm
by friz
+1 the ability to suck the heat out of your camper at the end of the day is priceless. You also need to keep air moving to avoid condensation.

Sent from my SM-G930V using Tapatalk

Re: roof vent with or without fan?

PostPosted: Fri Mar 16, 2018 8:41 am
by John61CT
MaxxAir with the integral rain cover.

Not as low profile. . .