I have two maxxair vents on my roof. Fan in front and vent in back (actually ordered wrong back one and it has a light and fan, but I did not connect electric)

 

Jim you are referring to the Maxx dome vent in the back?
Do you get a breeze through the van? Are there any downsides? Thank you.

 

No dome, I got this one. Maxxair Vent Corp 00-003801 Maxxair Mini Vent 14" White front one is a 5100 (no remote control but reversible)

 

The RV mushroom vents seem to be only about $15. Hard for me to understand why these aren’t super popular to pair with a fan.

 

I think people don't add that type of vent because it never occurred to them to do it. They are common on moving vans and enclosed trailers. To get a good cross ventilation, I'd consider a wall mounted vent as low as practical.

 

I am thinking to install this

https://www.etrailer.com/RV-Vents-and-Fans/Maxxair/MA00-03812B.html

in the shower, just to move the moisture out.

 

@rockDAWG that seems like a good idea; that vent is powered though and I’m talking about a passive vent.
@surly thanks yeah it seems sensible. A low vent for cross ventilation would be good but would have rain and dust considerations (not unsolvable). Faroutride’s floor vent gets nasty per photo on their site. Also side vent would be conspicuous. Maybe I can fit a mushroom vent under a solar panel on roof for maximum rain prevention and clean look. We will see.
Appreciate all input.

 

@rockDAWG that seems like a good idea; that vent is powered though and I’m talking about a passive vent.

Understand, my use is different from yours. For passive vent, venting from the floor is better as others suggested.

 

Most of us use floor vents, Cool air rises up from under the van.

 

Rear door seems ideal for a passive intake vent. But make sure it can be closed off when driving. An opening rear window makes even more sense; if such a thing exists.

What 439 is talking about in case people keep picturing regular 14x14 vents:

 

For the floor vents are people seeing dust issues like Faroutride depicts? Nasty. Presume the dust filter works and can just be cleaned off regularly.

Floor Vent | FarOutRide

Ventilation is crucial to control temperature and moisture level. But without any AIR INTAKE, the roof fan won't be able to do its job!

faroutride.com

 

I like the passive vent idea and think it makes the most sense. I installed a floor vent. We close our while driving, and therefore dust intrusion is not an issue. The whole van got dusty in our trip to Death Valley, but that was not from the floor vent, it was from EVERYWHERE. Ha. I would avoid the dust screen that FarOutRide employed and just make it easier to close and open the vent for driving. If you want a ceiling vent, just be aware of the cross sectional area that is available for air flow. You want to have enough open area to allow whatever active venting you choose to pull air through the van effectively.

 

I suspect it's what's driving everyone's various decisions. If one is dedicating the roof real-estate, it seems more common to be 2 x 14" fan (MaxxFan or other) or one fan and one AC unit. If not dedicating roof real-estate, there's a solid argument for a low-placed intake (colder air plus low-to-high flow). And there's the "free real-estate" aspect of pulling it up from the sides and/or under the van - or using the D-Pillars LOW as the exit.

 

I think dust is pretty much a On-road/Off-road thing, I mostly stay on the pavement and I have no dust at all in five years of ownership. I never roll the windows down because a ton of dust blows in whether you are driving or parked. I stay in small campgrounds and friends driveways. I have two floor vents that can be opened or closed and I have a single powered roof vent.

 

My solution to having a cross breeze is super simple and requires zero modification. Just get a rainguard for your front seat windows and crack the windows. No worries about rain getting in and you get cross breeze if your rear fan is an exhaust.

 

I have not been real happy with the front window rain deflectors --> rear ceiling vent... you're not getting much meaningful air circulation because it hugs the ceiling. I would expect the same to be true of front --> rear ceiling fans.

If I redo my van, or do another, I will definitely include a floor vent at the opposite end, from a ceiling vent fan.

 

Would a floor vent with a PVC elbow below the floor pointing to the back help reduce dust?

 

How about a Flettner?

Flettner TCX-2 Rotary Ventilator | U.S. Upfitters

Flettner TCX-2 Rotary Ventilator

www.inlad.com

 

I just installed this floor vent - haven't hit the road yet, but expecting low dust due to location. Will have a dust filter that is removable from the inside for cleaning. If it backfires, I'll definitely update the post.

I was originally gonna do two roof vents, but went floor for cross breeze/more space for solar.

Why *wouldn't* you do the floor vent like this?

Was inspired by you all to go the floor vent vs dual fan route. Thank you. Going to try one to start & potentially add another if we want more intake. We're using the spot just behind the driver, with the big hole in the chassis down below. Well documented how to do this, BUT... Gonna go a...

www.fordtransitusaforum.com

 

Much of this discussion talks about combining two different functions: ventilation and cooling crossbreeze.

For ventilation, all you really need is an exhaust fan and one a couple of small intake openings. The intake air will naturally mix with the air in the van, and you will get decent ventilation even if the location of the fan/intake is not "ideal."

Location of the intake openings is more dependent upon how stealthy you want to be. For stealth, under the van makes sense. But as others have pointed out, stealth is mostly a myth these days, so a couple of conveniently located wall openings can work for most.

Nesting bugs can be a problem, and so it is important to screen these openings against bugs. Dust is also a problem, and so it is important to make them very accessible and easy to seal off when driving.

For cooling one's body, the best thing is a dedicated cooling fan that you can adjust to blow right on you at the desired speed.

 

Passive crossbreeze to exchange hot for cool air would be ideal, but not always practical for every circumstance. An outlet at the top and an intake down low, as far as possible from the outlet, creates the most air exchange. Theoretically, a venturi effect would be created by the heat rising and exiting via the top outlet, drawing in more air from the lower intake. That's all well and good in a Bell Jar, but real-world wind and other factors may foil that plan. For instance, the ground stays hotter in the desert at night from being heated all day, so drawing in air from down low is counter-productive. Having a motorized fan in the outlet forces it to function to draw in air from down low. Having a reversible fan would take care of changing circumstances.

 

My current vent challenge is trying to find a way to get adequate ventilation (for normal, cooking, and shower moisture) while also maximizing solar PV on the roof - if that is a concern for you too.

@Hein suggested his taller Transit rail towers (to raise the solar panels enough) and the Le Mans Rooftop Ventilator (which is low height profile) under the panels offset to the side of the roof where there is some space due to the roof curve.

If anyone has any more ideas, I would be appreciative. Thanks!

 

Appreciate all the info.

My plan was to have a forward mounted MaxxAir (don’t like it directly over my bed as I’m a light sleeper and don’t want the sun right there in the morning—also better to ventilate when cooking this way), two bug screens for the forward cab windows paired with wind deflectors, and a passenger sliding door window I can open. That’s plenty of air movement in the van. What it all lacks is airflow from the back of the van, thus my questions about a passive mushroom vent or floor vent. But I think I like @kenryan’s point best- just install a small fan in the back! Easy!
In future I might add a window in the back but I don’t know about that. A little 12V fan would probably be perfect in the meantime.
Thank you all!

 

Appreciate all the info.

My plan was to have a forward mounted MaxxAir (don’t like it directly over my bed as I’m a light sleeper and don’t want the sun right there in the morning—also better to ventilate when cooking this way), two bug screens for the forward cab windows paired with wind deflectors, and a passenger sliding door window I can open. That’s plenty of air movement in the van. What it all lacks is airflow from the back of the van, thus my questions about a passive mushroom vent or floor vent. But I think I like @kenryan’s point best- just install a small fan in the back! Easy!
In future I might add a window in the back but I don’t know about that. A little 12V fan would probably be perfect in the meantime.
Thank you all!

I did not like the light from the Maxxair when I park on the street below a street light. Solved that with 1" closed cell insulation foam plug cut slightly larger than the opening. Just stuff it in the opening. Also acts as insulation on cold nights.

 

LOL...yeah, I have one of those plugs (I used to have a camper). But that doesn’t work if you want ventilation at night 😂

 

I have a couple of floor vents up front I can close when driving plus side window vents, MaxxFan is in the rear. Works for me.

 

I bought a pair of these window vents from Eurocampers Expensive for what they are but very well made . I'd feel safe leaving the van with them in place. I don't have any experience as to how much air flow they'll allow sitting yet but hot air rises I don't think it makes much practical sense to cut a hole in the floor. If the fans on exhaust in the back in theory the air should move through the van and exhaust the hotter part.

Transit Window Vents Cab AirVent Inserts for Best Airflow

www.eurocampers.com

 

I picked these ones up: 2015 - 2021 Ford Transit Full Size Van Airvent Cab Window Inserts

 

Have had 4 mushroom vents on 4 ocean sailing boats, they don't let in rain, big waves or garden hose directed wash water. My rear Maxxair is currently acting as a passive because the circuit board is dead. As mentioned elsewhere, the air coming in hugs the ceiling, particularly if warm and it also lets in lots of dust in dusty environments. Sorry I did not do a floorvent before insulating the floor. Front windows cracked are a security risk if forgotten and insulated window covers further complicate that solution. Floor vent