Roof vent W/O fan?

[wjffineww]

Is it worth installing a roof vent without a fan? I will not have solar/other power source, so no fan.

 

[highdesertranger]

short answer is, yes. hot air rises so that would give it a way out. highdesertranger

 

[SternWake]

This fan is about 7 inches in diameter, and on lowest speed consumes 0.08 amps, and oh highest speed is 0.28 amps.

https://www.amazon.com/SilverStone-performance-speed-FM181-Silver/dp/B002M78L0A

8 hours at 0.28 amps is 2.24 amp hours consumed, assuming it was left on highest speed

The average engine starter battery in a Van is about 75 to 85 amp hours.

This fan is very quiet even at maximum speed and moves ~150CFM. Most full size vans are about 360 to 400 cubic feet so it would exchange the air inside once every 3 to 4 minutes, if the fan were shrouded within the vent opening, and another window were open enough to allow that much air to flow inward to fill what the shrouded exhaust fan removed.

So While the engine starting battery would not be super happy being depleted slightly, and its life would be reduced to some degree, the linked fan on its own would need to be run on highest speed for 142 hours straight before dragging a healthy fully charged 80Ah capacity starting battery to 50% state of charge, at which point starting the engine might become more difficult in colder weather.

When the engine battery eventually fails, replace it with the biggest marine battery you can fit in the original location.

Carry a jumper pack and keep it fully charged, if one is worried about not being able to start the engine. I recommend people do not use jumper packs as house batteries as it will degrade their small capacity quickly, and might not be available/able to jumpstart the vehicle when needed.

shop around:
https://www.amazon.com/Jump-N-Carry...d=1480896010&sr=1-32&keywords=12v+jumper+pack

 

[jimindenver]

Yes, very much worth it.

 

[wjffineww]

Thanks for the info, very helpful.

 

[TrainChaser]

Roof vents are all I've ever had, no fans. My first van had a vent already in it, and I camped quite comfortably from SoCal to Maine.

My next van didn't have a vent. In Las Vegas, in June. Aaaaaaaaaarrrrrrggggghhh! It was the first thing I put in. It made a lot of difference.

I don't know that I'll put a fan in my next one (with luck, next spring/summer), but it has to have a vent.

I've read about natural convection and passive cooling in homes. Decently designed homes (very much in the minority) have windows that can be opened positioned low on the coolest/shadiest side of the home. The cooling effect can be increased by planting bushes to shade that area, and moistening the soil there.

The hot side of the home has windows up high. As air heats up, it becomes lighter and it rises, flowing out of the high windows; this draws in the heavier, cooler air from outside on the shady side. The cooler air gradually heats up and rises, so there is some constant motion of air traveling through the house. It works best in dry air, and not so well in hot, humid areas. It isn't a/c, but it's better than sitting in a car facing the sun.

I will be attempting to use this passive cooling in my van. The vents will be in place, probably positioned just behind and between the front seats.

I intend to install a 6" diameter marine deck plate (http://www.starmarinedepot.com/seac...gcnFAzKd1eKl4yGHjutU8qQ-rJUjm0OlZDhoC1zPw_wcB) and install it in a clear area of the floor somewhere in the open toward the back of the van. I intend to have wire mesh covering it to keep out unwanted visitors.

I am hoping that when I park and remove the solid plate, the ground under the van will be cooler (maybe dumping some greywater there will help). Then, as the heat rises and goes out the vent, the air movement will draw cooler air in through the deck plate, so there is some air movent through the van.

I've never heard of anyone doing this, but I'm thinking that it should work, at least to some extent, and the cost should be minimal.

I don't think that leaving the floor opening open while driving would be a good idea, due to both the intake of exhaust fumes, and driving over hot pavement would seem counter-productive.

I am also wondering if the deck plate could be used as a source of heat in cold, sunny weather by ducting heat from a homemade solar collector to the deck plate and into the van, sort of like this http://www.motherearthnews.com/~/me...hash=9C3DBADA94D69FF686D5837B22DE563568DE2B6A and/or this:
https://s-media-cache-ak0.pinimg.com/564x/2d/1e/65/2d1e65b1a24cdd3de442cebea500be32.jpg

I have lots of idea. Some of them might even work.

 

[NeedAnEscape]

I will be attempting to use this passive cooling in my van.  The vents will be in place, probably positioned just behind and between the front seats.  

I intend to install a 6" diameter marine deck plate (http://www.starmarinedepot.com/seac...gcnFAzKd1eKl4yGHjutU8qQ-rJUjm0OlZDhoC1zPw_wcB) and install it in a clear area of the floor somewhere in the open toward the back of the van. 

I'd reccomend doing the opposite, with the roof vent at the rear and floor vent near the front. A floor vent at the rear is much more likely to let exhaust in than a roof vent if you forget to close it before driving.

 

[MikeRuth]

SW is absolutely right about the current draw, it is small but I want to add that the Maxx Air units are not as quiet as the Fan-tastic Vent fan units.

I have a new Fan-tastic ready to install just because of the noise. Maybe I got a bumm unit IDK. I'm extremely hard of hearing so it really isn't a big deal for me but I do know from others that have heard it and what thy say.
Oh and as to keeping it cooler, no doubt that the fan makes a TON of difference. My van essentially never exceeds the outside air temp now. On my Ford E-150 the unit is mounted to the rear and I have vent visors on the windows, crack the windos down to the edge of the visors and it moves a significant amount of air.
Mike R

 

[Almost There]

I am hoping that when I park and remove the solid plate, the ground under the van will be cooler (maybe dumping some greywater there will help).  Then, as the heat rises and goes out the vent, the air movement will draw cooler air in through the deck plate, so there is some air movement through the van.

Where you park will make a big difference in the temperature of the air under the van. In a paved parking lot, it's going to be hotter than the surrounding air. On grass, a whole lot cooler.

Please make sure that if you're dumping UNTREATED greywater that it is legally and ethically okay to do so. If it's treated greywater, (deodorant chemicals etc added) then it is NEVER okay to just dump it.

Personally, if I'm parked somewhere, the last place I want to dump greywater is beneath my vehicle.

 

[wjffineww]

Thanks for all the responses. I think I have actually decided to do a vent with a fan. Love the idea of the port in the floor.

 

[ArtW]

There was a post in Bob's blog about a guy who had a vent in the floor as well as one in the roof, seems legit

 

[GotSmart]

I went with the window rain guards.  I can have the window down an inch or so and nobody can tell.  With the roof vent, the van stays a lot cooler in the summer.  And I did not have to put a hole in the floor of the van.

 

[MikeRuth]

I went with the window rain guards.  I can have the window down an inch or so and nobody can tell.  With the roof vent, the van stays a lot cooler in the summer.  And I did not have to put a hole in the floor of the van.

Exactly what I did and do. Works great. 

Mike

 

[blars]

Thanks TrainChaser for the name of "Deck Plate", I've been looking for one size larger than the one for the sewer hose in my motorhome. (The hose fits, but I need to take the connectors off and put them back on every time I use it.) Ordered an $8 (free shipping) ebay special from china.

 

[Kathleen]

I went with the window rain guards.  I can have the window down an inch or so and nobody can tell.  With the roof vent, the van stays a lot cooler in the summer.  And I did not have to put a hole in the floor of the van.

I asked about rain guards in a recent thread. Was going to have the local dealer order and install Weather Tech front side window channel rain guards for my 2005 T & C Touring Minivan, cost $165 plus tax. Yes, that's a lot of money and I would love to get them for a lower price. But earlier I read lots of reviews on the cheapies at Auto Supply stores. Buyers said they didn't fit, cracked during install, windows didn't shut right. I need them for ventilation in hot and cold weather so I was going to pay dealer to make sure they were good to go.

I read the Weather Tech window rain guard customer reviews on Amazon tonight. Seems about half the people doing the install said easy, no problem. The other half said they did not fit, broke during install, damaged window molding, or just so bad they had to be returned. Instructions that come with them are inadequate. I watched the shorty video about doing the install myself. Many customers said it's not that easy.

Several questions:

I can get Weather Tech channel rain guards for my minivan from Autozone. Do other forum members find the in channel work well for front side windows?

Does Weather Tech make good rain guards?

Autozone has them in their warehouse and they can be shipped to my location in one day, pickup at store, where I can open the box and make sure they are not damaged. (A number of Amazon customers said they arrived damaged.)

If I order the Weather Tech in channel rain guards from Autozone they are 44.95 per pair in a light tint, 30 bucks more for dark tint. BIG QUESTION: is there a reason for the dark color? Is it aesthetics only? Or does the darker shade hide the fact that they window may be open an inch when passengers are not in the vehicle but valuables are???

Would prefer not to spend more if I can get away with the lighter cheaper tint. Thanks for any feedback you can offer.

 

[B and C]

I've had both the cheap stick on ones and the Weathertech.  The Weathertech are far better IMO.  These are all I buy anymore.  I like the dark ones because it helps with the sun sometimes when the sun visor won't do and you can't tell when the window is cracked.  They also fit a lot flusher to the contour of the vehicle.  

I have never had a problem with installation.  To make sure they are the right ones, hold them up to the window frame where the piece would fit in the channel.  Roll the window all the way down and stick one end in the channel while holding the other end low.  Flex it a little until you can get the other end started at the lowest point and slide up until level.  Slide all the way up into the channel making sure it is seated all the way.  I generally pull it to the outside edge of the channel to help the window get past it the first time.  Roll the window up and leave it for a few days.  You probably don't have to leave the window up, but I think it helps seat it in place.

My DW's flew out one time when she rolled the window down at speed.  It seems the window was pulling it down a little bit each time she rolled it down until it finally blew out.  It has only happened on this one vehicle on the one side.  Now each time she rolls the window down, she pushes the Weathertech back up into place.  I think I may try a thin piece of double stick tape on it to see if that will help hold it up in the channel.  I don't know if it is the window channel on the door or the Weathertech that is causing the problem.  This is the only vehicle it has happened on.

I have had the cheap stick on ones crack and break in strong side winds at speed.

 

[GotSmart]

kathleen, 

Check this site out. About $35 with shipping. They can be returned, as Rock Auto is the top seller in the Automotive industry. They guarantee everything.

http://www.rockauto.com/en/catalog/...+v6,1430738,accessories,side+window+vent,1124

I have had stick on shades for three years now. The 3M tape works great. Never a problem.

Discount code
5311227947463423 5% 01 / 01 / 2017

 

[SternWake]

I have the stick on ones from AVS on my 89 dodge van installed for nearly 3 years now.

They do limit the amount the wing window can rotate out. I do not really use them for their intended purpose. I like the reduced wind noise at highway speed, and the sun shading at certain times of day.

My ventilation is forced by 12vdc

 

[Kathleen]

I've had both the cheap stick on ones and the Weathertech.  The Weathertech are far better IMO.  These are all I buy anymore.  I like the dark ones because it helps with the sun sometimes when the sun visor won't do and you can't tell when the window is cracked.  They also fit a lot flusher to the contour of the vehicle.  

I have never had a problem with installation.  To make sure they are the right ones, hold them up to the window frame where the piece would fit in the channel.  Roll the window all the way down and stick one end in the channel while holding the other end low.  Flex it a little until you can get the other end started at the lowest point and slide up until level.  Slide all the way up into the channel making sure it is seated all the way.  I generally pull it to the outside edge of the channel to help the window get past it the first time.  Roll the window up and leave it for a few days.  You probably don't have to leave the window up, but I think it helps seat it in place.

My DW's flew out one time when she rolled the window down at speed.  It seems the window was pulling it down a little bit each time she rolled it down until it finally blew out.  It has only happened on this one vehicle on the one side.  Now each time she rolls the window down, she pushes the Weathertech back up into place.  I think I may try a thin piece of double stick tape on it to see if that will help hold it up in the channel.  I don't know if it is the window channel on the door or the Weathertech that is causing the problem.  This is the only vehicle it has happened on.

I have had the cheap stick on ones crack and break in strong side winds at speed.

 

[Kathleen]

Thanks, Brian, for taking the time to tell me your experience. I'll print your info and take it with me when I do the install. Interesting that the darker ones fit better. Seems like they'd be the same size. I did realize they'd provide better protection from solar rays and would hide the fact the windows are rolled down a bit. So, I'll most likely pay a bit more and get the dark ones. I rode around the mall parking lot today to look at rain guards on vehicles. They were ALL the darker tint.