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How to Install a Maxxair Roof Vent Fan in a DIY Camper Van Conversion

We’ve opted against adding an air conditioner in our campervan, so we needed to maximize airflow.  What better way to maximize airflow than with a MaxxAir MaxxFan Deluxe? I mean, it’s in the name!

Another reason we opted for this particular model, theMaxxFan 7500k, was because it has an aerodynamic, rainproof design that allows you to keep the fan running any time – from driving down the road to a rain shower, we should be able to keep the fans going whenever we want to.


I mean, we can’t say for sure yet, but theoretically having 2 MaxxFan Deluxe fans in the campervan will mean that we can circulate enough air to replace the air in the van once every 20 seconds.  Basically, we can create our very own wind tunnel in the van!  That should be cool enough in most temperatures.

Total Project Cost: $689.93

Tools/Items You Will Need


Overcome your fear of heights:   We’re going to be on the roof of the van for this one, so this is a grand time to face your fear of heights.  Practice your cat-like reflexes on your favorite balance trainer.  Seriously, though, you’ll be walking delicately along the roof of the van, so take proper precautions.  

Cut a Hole. The hole for the MaxxFan Deluxe should be 14″ x 14″ square.  We simply measured where the center of the cutout would be, marked 7 inches on each side of it, then set the flange for the fan down on those marks and used it as an outline.  Then we used an angle grinder to cut the hole.  It would probably be easier to use a jigsaw, but we forgot to get a metal cutting blade and, let’s be honest, we’re impatient.  So angle grinder it was, and it worked just fine!

NOTE:  They make an adapter for the sprinter roofs so you don’t have to do any fancy cutting to avoid the roof ribs.  This is a REALLY good idea.  Here is a link to that product. (Roof Vent Adapter)

Clean the metal and apply sealant. Your sealant needs a clean surface to adhere to, so make sure the metal that you just cut is clean and free of dust.

 Place a strip of Dicor butyl tape down around the outside of the 14″x14″ hole.  You’ll only need one strip of this on each side, so you should use less than 5 feet of the tape per fan installed.  30 feet was the smallest roll we could find, unfortunately. Around the butyl tape, we also applied a thin bead of Sikaflex roof sealant.

This is self-leveling sealant that is made for roof applications.  It is very sticky and doesn’t ever really dry all the way since it is self-leveling, kind of a constant gel so it doesn’t crack.  We used less than one tube of Sikaflex for the entire project and sealing a few other holes around the campervan.  That stuff goes a long way, even with Nate being quite generous on his application!

Install the flange: Make sure the little metal clips are facing the sides of the van or wherever you want the side of the MaxxFan to face and put the flange down on top of the butyl tape.  Screw the flange down, making sure you don’t use the wrong screws like we did the first time.  Not a huge deal, just a quick trip to Ace to fix it that we didn’t want to do.  Reading the instructions prevents these issues.  But who does that?

More Sealant! No one wants a leaky roof, so of course, more sealant is in order here!  We added a bead of sealant around the edges of the flange and on top of the screws.

Place the fan on top of the flange.  As simple as this sounds, putting the fan in place was actually more difficult than we thought.  Pro Tip: pop the metal clips up about 1/8th of an inch using a screwdriver before you put the fan in.  That gives you a little wiggle room to get the holes lined up properly.

The instructions say to make sure they are down, but that is totally untrue.  Up worked way better! Once the holes are lined up, screw the fan in place with the 3/4 inch #10 screws (we know this because we had to buy more, but they are included for you).

Once that is complete, the only thing that is left to do is to wire the fans to your 12v distribution fuse block and install the trim ring. Installing the trim ring is covered in the installing the ceiling section of this build.


Saturday 20th of August 2022

Hey! I have recently purchased a 2004 sprinter that has a previous diy camper build. The build isn't bad but its not great and I plan to update a lot of it. The wall and celling paneling is already insulated and is good enough to keep. That being said I don't think I will run Romex for ac outlets because I can not really hide the wiring. I purchased your budget friendly 2000w wire diagram and it shows an ac distribution panel. Is there a safe alternative you suggest? Like a power strip that I can wire to the Renogy 2000w inverter/charger? I will likely have a few more questions because I am going to mix and match a bit with your line diagram so if there is a better way of connecting with you just let me know. Thanks!!!


Thursday 30th of June 2022

This is truly the worst way to install a roof window Polyurethane sealant over a butyl tape is major fault no1


Sunday 5th of June 2022

Have you found any issues with overvoltage with your Maxx fans? I am reading threads about Maxx fans (and some other 12v appliances) requiring voltage regulators. Any thoughts on this?


Thursday 23rd of September 2021

I have 2 maxxair deluxe fans and I’m about to wire them to my DC distribution panel. Do I need to wire each fan separately to its own fuse slot or can I wire them together into one?

Gary Menendez

Tuesday 3rd of August 2021

Hi Nate....I have found your posts and tutorials helpful for my 2020 Transit build, and I bought your hi-def wire diagram, which was very useful....thanks. Have you heard of problems with the MaxxFan not functioning, and actually frying, if the voltage is over 13.8v? My system is routinely at 14.1v or even 14.2, and when I turned the fan on the first time it ran for 15 seconds and shutoff. I reset it and tried again, and now it doesn't work at all. I only read great things about the Maxxfan before buying. the literature said a minimum of 12 v. required, but made no mention of maximum. Now that I am in troubleshooting mode I see dozens of posts by folks with the same problem. People are suggesting inline diodes or voltage regulators, both of which consume power. Do you have any thoughts on this? Did you have any issues? Gary