Positioning a Roof Vent/Fan?

[dr_nelson]

Hey y'all,

As of now, I am planning on installing one roof vent only (maxxfan or fan-tastic). The rest of the roof will be taken by solar. But for airflow, I will add at least two 'larger' holes in the van-floor, that I can close airtight if wanted, since exhaust fumes are dangerous. I will also get a portable fan inside the living area, since it can get close to 100 F in the summer where I am.

So, I know every roof is different, every roof is set up differently, and so is the interior (location of bed or kitchen).
But I was hoping to get some insight of those that are experienced (before I cut a hole in my high-top), where you guys have located your roof vent. Is it more over your bed (towards the back) or more towards the kitchen (towards the front) or just in the middle (I mean front/back middle, not driver/passenger middle)?
Also, would you place your vent differently, if you could do it again?

Any input appreciated!

 

[AbuelaLoca]

Have you insulated your high top? I'm wondering if I should put the fan in before insulating or after? Mind if I add to your topic?

 

[dr_nelson]

Have you insulated your high top? I'm wondering if I should put the fan in before insulating or after? Mind if I add to your topic?

I don't mind at all!

My high top is not insulated, yet. But I had the same question, but then I decided it is almost neglectable. Installing the fan with insulation already in place does not make it that much harder or more expensive.
But one may want to know where your wires or tubes are running through and not cut them, especially if you have them covered with ceiling trim.

 

[MikeRuth]

On my Ford E-150 I placed it as close to the rear as was practical. Leaves me room for the solar panels up front and in my opinion moves the largest amount of air from front windows to the fan. In fact just yesterday on a mildly warm day the inside had heated up pretty good, I turned it on and then checked again in five minutes. About the same as the outside air temp that quick.
Works for me.

Also for me If I want, I can reverse the fan and have cool air blow down on me on those hot summer nights. My bed is just off center of the fan.

Mike R

 

[MrNoodly]

I put mine where I can reach it from the driver seat in case I forget to close it before driving, or so I can open it and switch on the fan before I park in hot weather.

 

[Wandering i]

Saw this, http://www.fantasticvent.com/fan-tastic-vent-s-retail-ez-breeze-fan.html. Haven't looked at enough and don't see dimensions but might be option as states can use without opening lid, so might work under panel

[font=Arial,]EZ-BREEZE
THE ALL NEW REVOLUTIONARY FAN[/font]
From the performance leader in RV ventilation, the all NEW patent pending EZ-Breeze is uniquely designed with a built in rain cover to provide air circulation throughout the RV without ever needing to open the dome. 

 

[Almost There]

My only recommendation on where to locate a roof vent is this - do NOT put it right over top of your bed!

Even with a Maxxair or Camco cover over it, you stand a chance of having a wet bed sooner than later. If not from splash then from a leak.

We've (collective we) been putting roof vents in our vans for over 40 years now and I can tell you that to a person, anyone with one over their bed will regret it at least once....

 

[Reducto]

Rain getting in is a problem with the fantastic fan, not the Maxxair. I have not had a hint of water come in since switching over and I've been in some decent storms.

With the FF I was getting lots of water and direct sunlight that I didn't want.

As far as where it should go, I went with as far back as possible to leave room for solar in the front. That leaves the floor holes in the front, rather than in the back where they would pull in more exhaust when the engine is running.

I put mine in the middle (left-right) which I supposed looks better, but does limit things I bit. If it were off to the side it might actually make it easier to fit one more panel or some sort of cargo carrier on the other side.

 

[slem]

Have you insulated your high top? I'm wondering if I should put the fan in before insulating or after? Mind if I add to your topic?

I made the determination on how many solar panels I would need on the roof then installed a fantastic fan not to interfere, then insulated my interior.

 

[Vagabound]

Hey y'all,

As of now, I am planning on installing one roof vent only (maxxfan or fan-tastic). The rest of the roof will be taken by solar. ...

Excellent thread. I've been thinking about this exact thing myself, and just haven't taken the time to start the thread.

In my case, having a box truck, and one in which I decided to keep the roll up door. the only place the fan can go is the front half of the box somewhere. Additionally, roughly the front quarter of the box is taken up by my bed with under-bed storage.

Although I have no experience with it, I was very reluctant to put a fan over my bed, so I'm happy to read the comments from Almost There.

So, that actually leaves only the second quarter of the box roof area as a possible location for the fan. It is easy to get fooled into believing that a box truck roof would allow you nearly unlimited places to put the fan. Clearly, that isn't the case. In fact, I'm limited to a space of only four feet long by eight feet wide. And even less if other practical considerations are taken into account.

Regarding location, being already restrained longitudinally, my issue is lateral location. Simply, does it make any real difference whether I put the fan on the left side of the box, in the center, or on the right side?

----------

A related issue that I'm dealing with now regarding planning for the fan is about roof sealant. I will be putting on some white elastomeric cool roof sealant in the near future.  In my case, it is practically mandatory, and the pros and cons of all of that have been covered in another thread. 

This specific issue relates to the fact that the sealant will end up happening before the fan gets installed. My concern is having the roof sealant interfere with a later fan installation, in terms of the fan flange being able to seal properly on the roof. 

So, I've been wondering if I should just apply the sealant to my aluminum roof, ignore the future fan location, and deal with that location later, or figure out the fan location, trace it out on the roof, and carefully paint around it?

Recommendations?

Tom

 

[highdesertranger]

what type of sealant? got a link? I think it would have to do with the type of sealant. I am very interested in this because the roof of my trailer is going to need to be sealed. highdesertranger

 

[Vagabound]

...
[font=Arial,]EZ-BREEZE
THE ALL NEW REVOLUTIONARY FAN[/font]
...

Sounds cool. Read some of the website advertisement. I get a little bit suspicious when someone describes their product as being made from "material" instead of telling me which material it is.

Tom

 

[SternWake]

I think the e-z breeze is kind of like a low profile rain resistant lower CFM fan for when 800CFM flow is not needed and 350 is fine.

My roof vent is 2 counter rotating inline 120MM fans one rated at 110 cfm the other is 52cfm. I doubt they can move 162 cfm together, especially since they blow into a restrictive mushroom vent whose aperture is only ~100MM.
However when on high, I can cook pasta inside without fogging my windows, as long as it is not raining outside.

My point is, 350CFM is a respectable amount of airflow, as long as there is an inlet cabable of replacing the air exhausted.


I think the EZ breeze fan would be a good fit for a full size rv bathroom, or a Van, but if one has to cut a 14x14" hole anyway, the larger fans with their much higher airflow would be more desirable.

 

[dr_nelson]

I made the determination on how many solar panels I would need on the roof then installed a fantastic fan not to interfere, then insulated my interior.

Yup, exactly my thinking. I will most likely go with 3 100W solar panels, but since I have not decided yet which ones (and still saving up some $$$) and how exactly to mount them on my high top, I haven't even bothered ordering a roof fan, yet. I am still contemplating whether I should go with those rather expensive gutter roof racks for high-tops or with simple Angle Alumimum bars (putting two of those "L"s together can make a Z-bracket).

 

[Vagabound]

... still contemplating whether I should go with those rather expensive gutter roof racks for high-tops or with simple Angle Alumimum bars ..

I think you'll find the aluminum angle material to be pretty expensive as well. I bought a two foot section from Lowe's and it cost me $15 as I recall.

Tom

 

[Vagabound]

what type of sealant?  got a link?  I think it would have to do with the type of sealant.  I am very interested in this because the roof of my trailer is going to need to be sealed.  highdesertranger

Assuming now that it was for me, somehow I overlooked your post and question earlier. Maybe small font blindness. Sorry.

The brand of cool seal products that I'm looking at is called Henry. Home Depot carries it. Have not settled on exact one yet because I have not given it sufficient attention. However, I'm shopping for characteristics such as elastomeric and white colored. The attached photo will give you an idea of one product that matches. The five gallon bucket is a better per gallon deal. As I recall, it runs about $85.

Tom

 

[highdesertranger]

thanks Tom. has anybody used Henry's on a trailer or RV roof? we have used it before at a couple apartment complexes I work at with less than good results. the roofer's say it's junk. I do know it didn't work for us. highdesertranger

 

[Vagabound]

thanks Tom.  has anybody used Henry's on a trailer or RV roof?  we have used it before at a couple apartment complexes I work at with less than good results.  the roofer's say it's junk.  I do know it didn't work for us.  highdesertranger

I've never used that brand before. However, it is the most expensive brand at Home Depot. That doesn't have to mean anything, but it seemed to be a positive indication. Somewhere along the line I think I read some reviews on it that were pretty good. All of it foggy now.

So what problems did you or anyone else experienced with Henry products?

Tom

 

[dr_nelson]

I think you'll find the aluminum angle material to be pretty expensive as well. I bought a two foot section from Lowe's and it cost me $15 as I recall.

Tom

Well, those vantech roof racks for the gutter are over $200 each (per bar). They're the ones for the econoline with hightops, and I like the idea that I would not have to drill further holes into my high-top and just use the rain gutter of the van. But the price...  :-/

 

[highdesertranger]

don't buy metal at home improvement stores. go to a metal supply yard. highdesertranger