Fan placement and ventilation

Our van is a 2013 Sprinter which was formerly a passenger edition with permanently shut glass windows all around and a useless rear AC unit. When we removed the rear AC there was a ~14 x 30" hole in the ceiling which seemed like a perfect fit for the 14x14" opening that our MaxxAir (in and out) fan needed and we installed the fan there (i.e. near the front of the cabin)

When the rear doors of the van are open the fan generates a pleasant breeze throughout the cabin and all is well. When all doors and windows are closed however, the fan works a little harder and the incoming air is not noticable or sufficient on hot days.

With benefit of hindsight I think that a smarter spot to place the fan might have been near the end of the cabin such that slightly opening the front passenger windows would have done the trick. I don't know if this would have reduced the fan's effectiveness with respect to the shower and stove near the front, or how to evaluate the installation trade offs... In any case regrets are for fools.

For now, I'm wondering what the path of least resistance is to creating an opening in the back (doors, floor or ceiling) which let's enough air into the cabin.

Any ideas or suggestions would be welcome.

Thanks!

AMA makes replacement windows with operable sliders for most locations.
I just picked a random example...you can check out the other offerings.
https://www.vanwindowsdirect.com/co...arter-half-slider-window-sprinter-144wb-07-18
This likely the easiest way to get a source of fresh air.

PIka Van makes powered exhaust vents that go in the very top of the rear doors in a high roof.
I’m not sure if they are only exhaust or reversible? https://www.instagram.com/p/ByJoYqeBAIE/

Maybe have your Maxxair running intake and the rear door vents (PIka) exhaust?
Or rear windows open and front Maxxair set on exhaust?

You might consider our door prop.
It holds the door slightly open using the OEM
latch which can then be locked for security.

Below is a short clip of how it works. (shown on the Transit)
This is the older version but the new on works the same and also has a bottle opener.

All the best,
Hein
DIYvan

https://youtu.be/HkShSs0x3e0

I use the first version (2 opening positions) of this product often to keep rear passenger side door crack open, Hein sells current version now. You can also get screen for rear opening. https://www.ebay.com/itm/Door-Prop/142911830647?hash=item2146357a77:g:jOgAAOSwPfhbe0S8

That door prop looks like a really nice solution.

I am fitting a fan in the standard position just behind the cab, but have also wondered if that's going to allow enough ventilation in the rear of the van.

I've left space on the roof so that I can retro fit one of those marine solar powered vents.

Here's one example of what I mean
https://www.amazon.com/ECO-LLC-Moun...ine+roof+vent&qid=1563777065&s=gateway&sr=8-3

There are lots of different ones out there. I'd want to be able to switch it on/off (not all do) and be able to choose if it pulls air in or out (not all do). Some have build in lights which I'm not bothered about personally.

I think with one fan pulling air in and the other pushing it out you should be able to get better air flow.

I've also seen for sale some solar powered fans that clip onto the driver/passenger windows but they've all looked a bit cheap and unreliable. I could be wrong, but they didn't inspire me.

I just finished a 2015 passenger; I removed the AC and installed eight max air with Hein’s CNC plate. I added a second fan in the rear and replaced the emergency exit window with a T vent. With those three, the amount of ventilation is excellent. I had forgotten about Hein’s rear door adapter, and will be ordering one of those for my client as well.

The only downside of the two fans in that placement is that you can just barely fit two of Renogy’s slim panels in between, but so far 200 W has proven more than sufficient for her needs and she is back to 100% by mid morning.




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GSWatson said:

I just finished a 2015 passenger; I removed the AC and installed eight max air with Hein’s CNC plate. I added a second fan in the rear and replaced the emergency exit window with a T vent. With those three, the amount of ventilation is excellent. I had forgotten about Hein’s rear door adapter, and will be ordering one of those for my client as well.

The only downside of the two fans in that placement is that you can just barely fit two of Renogy’s slim panels in between, but so far 200 W has proven more than sufficient for her needs and she is back to 100% by mid morning.

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Click to expand...

Nice job!

I see a lot of folks installing two fans and I haven't been able to make sense of it. The cabin is ~90 sqft. The MaxxAir or Fantastic fans' capacities are 900 CFM. I would think one fan ought to be way more than sufficient if the appropriate vent openings are in place.

What are your thoughts on this?

My MaxxAir just arrived today - it's still in it's box waiting to be fitted hopefully tomorrow.

I only bought one partly because I wouldn't have room on my roof for my 2 x solar panels otherwise (MWB) and partly because I also thought that a fan that size should be able to move enough air given the relatively small size of the van.

However, that air has to come into the van from somewhere and that's where I can see that two fans make for a predictable repeatable consistent flow of air. Especially if you're showering or doing a lot of cooking inside the van.

I love the simplicity of Hein's door latch to allow for a good entry point for air, but for now I'm just going to fit the MaxxAir and see if I need more than it can deliver.

I have one MaxxAir in the rear of my van and the Weathertech front window vent covers, and the one fan does a reasonable job with those cracked open.

On the passenger, the rear fan was due to a lack of ventilation options in the rear. And with Theo fans, one on push and the other on pull, we can get reasonable air exchange with each on a lower and quieter fan speed that one on high.

If anyone is interested, I have an extra fan left from the build that was on backorder from camping world and only just arrived, three months late…. New in box.


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I find one centrally located Maxxair fan more than sufficient. I rarely operate the fan above 20-30%. I open one CR Laurence vent in front to create a nice breeze through the cabin. When sleeping we typically crack open one rear slider with everything else closed and fan set to 10%, “silent mode”. This creates a gentle draft across bed area. The fan is positioned directly between my range top and my shower so it performs multiple duties. I purchased a smaller 6” vent fan for the shower but quickly realized it was not needed.

Also, fewer roof mounted fans leaves room for more solar. I find the solar panels significantly reduce the heat load on the van.





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Good point about solar panels keeping van interior cooler. My old Landrover IIA station wagon had a tropical roof and it made a huge difference.

Hein's door prop works really well. I have the older version, and usually install it on the smallest opening. Even without any fans running, there is a nice draft running through the van if I leave the front windows rolled down all the way.

I've also driven very short distances with it open too.