Roof vent vs no roof vent in a conversion van.

[East]

I've been contemplating getting a fantastic fan to increase airflow. I'm not sure if it will make a big difference though. Currently I have two swinging side doors, each of which have swing out windows, along with three sliding windows along the bottom of the conversion van's larger windows (2x on drivers side, 1x on passenger side). The back windows do not vent. I have rain guards on the front windows that allows me to crack them. I've been using this product somewhat effectively in my windows but I think a roof fan might be more useful considering hot air rises and technically there is some pocket of air that is not circulated well towards the roof.

If I did have a vent fan though, I'm not sure how this would effect overall airflow because I'd have to offset it to the drivers rear side of the vehicle. It's really the only usable space and I'm not willing to give up my roof cargo carrier.

Do you think in my situation this would be a waste/overkill or useful?

 

[Almost There]

Do you think in my situation this would be a waste/overkill or useful?

Absolutely useful!

As you've noted, heat rises. Those side slider windows do nothing (I've had them before) for exhausting hot air, they're too low. They're effective for letting in fresh air if they're faced in the direction of a breeze but that's about it.

Positioning like you showed on the diagram might mean that you would have to run it at a higher speed than most of us with centered fan units would, but it will still draw the heat out.

If that is over the bed, a MaxxAir cover (or another brand) will be absolutely vital as well so as to prevent rain from getting in. That one day that you go for a walk in bright sunshine and have a rain shower when the vent was left open will pay for the cover all by itself..

 

[66788]

I would not have a van without a Fantastic Vent or a MaxxAir vent.

Mine is located at the highest point of the roof and when hot I close all the windows except for the rear tilt out ones and the powered vent draws fresh air right over the bed and sucks out all of the hot air. I leave it on all night long without problems.

An added bonus is that mosquitos are drawn to the carbon monoxide we emit with out breath when we exhale, so that exits out the roof vent drawing the mosquitos to the roof vent which has a bug screen on it, not to the rear windows which are the air intakes and act as a laminar flow, not allowing any carbon monoxide to exit out the rear.

There are those who will tell you differently. A few have never owned a powered roof vent.

 

[Satellite5812]

I don't have a roof vent yet, but I'm definitely planning to get one. During my "testing week" trip in the desert, I was able to keep my van cool enough to be comfortable on the floor by leaving all the doors open. But even standing, there was a noticeable temperature difference. Plus, you can't keep the doors open all the time.

 

[B and C]

Putting it where your drawing shows , you will be installing it over those valleys in the roof.  You will have to extra careful to get it sealed to the roof well.  The center rear has a flat spot made just for one of these.

Brian

 

[Tinman74]

I had 2003 Dodge conversion high top van. It had 2 slider windows down low + the two tilt outs on the side barn doors and also on the two back doors.
I had installed two" fans in the two back door tilt outs. It moved a nice breeze across the bed area but the hot air just clung to the ceiling area making it very uncomfortable. I now have a 99 Road trek with a fantastic fan and it makes all the difference in the world. I am sure it would have made a big difference in the conversion van as well.
Bob

 

[East]

Thanks, everyone for your replies. I will go ahead and order one sometime soon. I just wanted to clear up that my drawing isn't 100% accurate, it will definitely be offset, and therefor the curve of the roof might cause issues with sealing, but it's not as offset as close to the edge as is shown in the drawing. It definitely will be off center though.

As long as it being off center won't make it completely useless I think the addition will be a worthwhile investment based on the replies here.

 

[Almost There]

I'd suggest getting it as close to the center of the side to side dimension as you can as opposed to as far out to the edge.

With the cargo carrier in place, you should be able to put the roof vent within a couple of inches to the side of it. How far back you want to place it will depend on how sensitive your PV panels are to shadowing.

If you are in an area where there are ridges in the roof, lay in extra dicor in the valleys then a top layer of it that covers the whole outline of the vent.

 

[TMG51]

Thanks, everyone for your replies. I will go ahead and order one sometime soon. I just wanted to clear up that my drawing isn't 100% accurate, it will definitely be offset, and therefor the curve of the roof might cause issues with sealing, but it's not as offset as close to the edge as is shown in the drawing. It definitely will be off center though.

As long as it being off center won't make it completely useless I think the addition will be a worthwhile investment based on the replies here.

It's been said already, but, that fan would make a huge difference for you no matter where you put it. I wouldn't go without one.

Consider that when set to exhaust, the fan is removing up to 900 CFM of air from your van. This ensures that air is being exchanged MUCH better than simply leaving windows open. Also, because this volume of air is being removed and the same volume of air must replace it, this means if you want to sit in front of a breeze you can choose where to create one by which windows you open. In other words, even if the fan is on the other side of the van, you could be in the back with two windows open and the fan set to exhaust and you would feel a strong breeze moving over you while the air is replaced.

There's no question about its value.

 

[East]

I'd suggest getting it as close to the center of the side to side dimension as you can as opposed to as far out to the edge.

With the cargo carrier in place, you should be able to put the roof vent within a couple of inches to the side of it. How far back you want to place it will depend on how sensitive your PV panels are to shadowing.

If you are in an area where there are ridges in the roof, lay in extra dicor in the valleys then a top layer of it that covers the whole outline of the vent.

Good idea, thanks for the constructive input. I think I will get it right up against the cargo carrier. As for the solar being shadowed I'm pretty used to adjusting my vehicle to keep the shadows from being cast by the cargo carrier so they would be in the rear, so I guess there's not much more I can do but continue to do what I've been doing which is just adjusting my parking.

It's been said already, but, that fan would make a huge difference for you no matter where you put it. I wouldn't go without one.

Consider that when set to exhaust, the fan is removing up to 900 CFM of air from your van. This ensures that air is being exchanged MUCH better than simply leaving windows open. Also, because this volume of air is being removed and the same volume of air must replace it, this means if you want to sit in front of a breeze you can choose where to create one by which windows you open. In other words, even if the fan is on the other side of the van, you could be in the back with two windows open and the fan set to exhaust and you would feel a strong breeze moving over you while the air is replaced.

There's no question about its value.

Just to be clear, I am using a stand alone fantastic fan in my windows, as I stated earlier. Definitely not just leaving my windows open and hoping for the best.

 

[Almost There]

Good idea, thanks for the constructive input. I think I will get it right up against the cargo carrier. As for the solar being shadowed I'm pretty used to adjusting my vehicle to keep the shadows from being cast by the cargo carrier so they would be in the rear, so I guess there's not much more I can do but continue to do what I've been doing which is just adjusting my parking.

Make sure that you don't get it so close to the cargo carrier that you can't open the lid of the cargo carrier.

If I remember the design of the cargo carrier the lid is hinged part way down the side creating a zone of dead space on the hinge side when the lid is open.

I'd use duct tape to set the roof vent assembly in place where you think you want it and then double and triple check to make sure that you've got clearance for everything! It's the old measure 3 times, cut once thing kicking in...

 

[SoulRaven]

I'm not a huge fan of roof vents or anything that requires putting a hole in a roof.

A window fan aimed slightly upwards will keep the whole van, floor to ceiling just as cool as a roof vent will.

 

[accrete]

I would not have a van without a Fantastic Vent or a MaxxAir vent..

X2 !

We swapped out our FF for a MaxxAir and the ability to open the unit in a downpour is great. And there is no way my wife was going to allow me to put one of those big ugly fan covers on her DD !

Not stealth during this trip, but you can see the two MaxxFans on both rigs. Nice a low profile going down the road. Once in camp open them up for nice airflow.

Thom

 

[66788]

I would not have a van without a Fantastic Vent or a MaxxAir vent.

Mine is located at the highest point of the roof and when hot I close all the windows except for the rear tilt out ones and the powered vent draws fresh air right over the bed and sucks out all of the hot air.   I leave it on all night long without problems.

An added bonus is that mosquitos are drawn to the carbon monoxide we emit with out breath when we exhale, so that exits out the roof vent drawing the mosquitos to the roof vent which has a bug screen on it, not to the rear windows which are the air intakes and act as a laminar flow, not allowing any carbon monoxide to exit out the rear.

There are those who will tell you differently.   A few have never owned a powered roof vent.

Dang, it's not carbon monoxide, it's carbon dioxide!  See what happens when one posts stoned?  

 

[MikeRuth]

Just my 2 cents, none of these are going to leak if installed properly. I have heard it time and time again, they are always going to leak, NOT SO!. Now maybe after 10 to 20 years but if that's the case no reason at all to not take a day, remove clean and remount, done another 10 to 20 years. \\

Real confident in my install and it's been exposed to some serious down pours.

MIke

 

[MikeRuth]

I've been contemplating getting a fantastic fan to increase airflow. I'm not sure if it will make a big difference though. Currently I have two swinging side doors, each of which have swing out windows, along with three sliding windows along the bottom of the conversion van's larger windows (2x on drivers side, 1x on passenger side). The back windows do not vent. I have rain guards on the front windows that allows me to crack them. I've been using this product somewhat effectively in my windows but I think a roof fan might be more useful considering hot air rises and technically there is some pocket of air that is not circulated well towards the roof.

If I did have a vent fan though, I'm not sure how this would effect overall airflow because I'd have to offset it to the drivers rear side of the vehicle. It's really the only usable space and I'm not willing to give up my roof cargo carrier.

Do you think in my situation this would be a waste/overkill or useful?

I think that location is just dandy myself. Mine is in the middle and just barely comes into the ribs. I can not begin to tell you how much it keeps the interior cooler. 

Mike R

 

[highdesertranger]

dang I wish them skeeters were drawn to carbon monoxide. we could kill the by the millions. higdesertranger

 

[VenFan]

I'd put it closer to center of van so incoming air would travel over wan's cargo area before escaping trough open windows. You can also put it in the rear however i'd keep rear window and left rear window closed so air dont escape trough them right away.

P.S. My Experience with conversion windows also shows no airflow at all even with all windows open, however when you open side and rear doors it makes substantial difference.

Perhaps if rear and side door windows opened not just 15 degrees, but actually 90 degrees that would have made the difference.

 

[TMG51]

Just my 2 cents, none of these are going to leak if installed properly. I have heard it time and time again, they are always going to leak, NOT SO!. Now maybe after 10 to 20 years but if that's the case no reason at all to not take a day, remove clean and remount, done another 10 to 20 years. \\

Real confident in my install and it's been exposed to some serious down pours.

MIke

100% agreed.

dang I wish them skeeters were drawn to carbon monoxide.  we could kill the by the millions.  higdesertranger

Just for a bit of trivia for anyone who doesn't know - those propane powered mosquito killing machines work exactly like this (but with carbon dioxide). They use the propane to generate Co2 and draw in the 'skeeters.