For ventilation of the camper van, we are using a Maxx Fan installed in the ceiling.
This page goes over the install.
The camper van with Maxx Fan in open position.
There are two fans out there that people appear to like for RV ventilation. The Maxx Fan and the Fantastic Fan. They both appear to be good products that do the ventilation and cooling job well. Both come is several models that range from fairly simple manual control up to full automatic with remote controls.
We had a Fantastic Fan in an earlier RV and were quite satisfied with it, but this time we decided to go with the Maxx Fan — it appears to have somewhat better aerodynamics and to handle ventilation in the rain or while driving somewhat better — will see. I don’t think you could go wrong with either brand.
The basic steps in installing the Maxx Fan:
- Decide where you want the fan
- Make a template to mark the cutout
- Cut out the hole
- Install Butyl Tape on fan cutout frame
- Screw fan cutout frame to roof
- Apply sealer over frame
- Install fan in frame
- Test fan for operation
See below for details on each step.
Decide Where You Want the Fan
The ProMaster has a nice spot to put the fan up near the front of the roof. If its installed there, you don’t have to deal with the ribs in the roof (see pictures below).
This location works out well for us in that we have a very long PV panel that has to go behind the fan, so the fan needs to be up near the front to leave room for the PV panel. Others may wish to install the fan further back.
Make a Template to Mark the Cutout
The fan needs a 14 by 14 inch cutout in the roof. The easiest way to get this right is to make a 14 by 14 cardboard template, and then place the template on the roof and draw around it to mark the hole.
Align the template carefully on the roof, and then mark around it, and cut the Hole.
Be careful about where you put your weight on the roof — it can be dented. Guy on the ProMaster forum reported some serious dents made by the people who installed his fan.
I used my tractor’s front end bucket as a work platform to avoid stepping on the roof a lot, but working from a ladder from each side will also work fine. If you are careful, you can kneel on the roof right over the roof support frame that runs just aft of the front doors.
At this point, I had to scrape away the foamed in place insulation around the cutout on the inside of the van. You will only have to do this if your insulation comes right up to the cutout.Once the cutout is done, clean up the sharp edges. It would be a good idea to apply some rust primer to the cutout edge at this time, but I did not.
Install Butyl Tape on Fan Frame
Clean up the area around the cutout where the butyl tape will be in contact with alcohol or the like.
Run butyl tape around the fan cutout frame. This butyl tape will get squeezed between the roof sheet metal and the fan cutout frame and will seal out water leaks. Be sure to run the butyl tape over the screw holes in the fan frame.
Screw the Frame to the RoofOnce the tape is on the frame and the sheet metal is clean, place the cutout frame in the cutout and center it up and push it down.
Do the final tightening with a screw driver. You should see a bit of butyl tape squeeze out along the frame.
Apply Sealer Over the Frame
Once the butyl tape has had a chance to finish its squeeze out, go around the cutout with a plastic scrapper to remove the excess butyl tape.
Next, you want to apply a sealer over the screw heads and along the edges. Maxx Fan mentions Dicor Lap Sealant, and I used it — it seems to have a good reputation. Our local RV parts place had it for $10 for a caulk tube. Its applied with a regular caulking gun. Silicone caulk would be another option.
Before applying the lap seal, do a cleaning with the alcohol or similar.
Now, Install the Fan in the Frame
At this point, Maxx Fan suggests installing the connectors on the electrical wiring so they are ready when the fan is dropped into the frame.
To install the fan assembly in the cutout frame, you first open the fan up all the way, and then just drop it into the cutout frame with the fan opening facing aft.
Line up the four holes in the fan with the 4 nutplates in the cutout frame, and secure with the 3/4 inch stainless screws.
Maxx Fan has just recently added a rubber gasket to the joint between the fan and cutout frame, and I found that I had to apply a fair bit of down force to compress the gasket enough to get the screw holes to line up.
Fan from the inside.
I still need to install the inside decorative molding, but will wait until the I decide on the type of ceiling we are doing.
You may want to figure out what kind of internal support frame will be needed to support the ceiling panels, and make this frame and use the same screws that are used to mount the fan to also secure the inside frame that supports the ceiling panels. See the comment on this from Colin in the Comments section at the end of this page.
There are models with and without remote.
Overall, the Maxx Fan appears to be well designed, and the installation is straight forward. The instructions that come with the fan are good. Will see how it does in service.
Cost and Weight
It took me about 3.5 hours to do the install.
The fan weight is 14 lbs less the 2 lbs of sheet metal that comes out.
Cost of the relatively fancy model of the Maxx Fan was $268 from AmericanRVCompany.com.
Another Ventilation Idea
John saw this page and suggested an alternative ventilation scheme. His suggestion is to use the ProMaster van’s own ventilation system and a new timer that would turn turn it on intermittently through the night — say, 5 minutes on and 15 minutes off. While this might not provide the level of ventilation that a Maxx Fan or Fantastic fan does, it does make use of hardware that you already have and reduces aero drag a little.
High Capacity Cooling
For the kind of camping we normally do, the fan alone works well for cooling. But, if you are in a hotter climate, cooling becomes more of an issue. These are a few thoughts on what you might do about a more robust cooling system.
The things that will make your camper van more comfortable in hot weather:
- Choose a reflective paint color (this makes a lot of difference)
- Insulate the van well — if you can include a reflective layer with an airspace in the insulation stackup, this helps with radiant heat transfer.
- Install something like a MaxxFan or Fantastic fan in the roof and use it in conjunction with open windows for cooling.
For dry climates, you might look at evaporative cooling — here is one DIY evaporative cooler that works, and can be run on a not too large house battery.
RV style air conditioners are also possible and work. The disadvantage being that the power consumption is so high that you are pretty much limited to being tied to shore power or a generator.
Kingtec makes a 48 volt DC model that is said to run on solar. This would likely take a 48 volt house battery back, and its running power appears to be (48 volts)(18amps) = 864 watts, so it would take a big solar installation to keep it satisfied even if its only running part of the time. Cooling output is 16,000 BTU/hr — probably more than is needed for a well insulated van.
Danhard makes some AC units for vehicles that fit inside the van.
One person on the ProMaster Forum is trying an inside room AC unit set up between the driver and passenger seats — this is the type with the hose that runs from the AC to a window.
Simple Cooling Methods Test
I did a simple test on the van to evaluate the effectivness of some simple cooling methods:
- White vs dark colors
- Simple ventilation (Maxfan and open window)
- Reflective window shades
Turns out these can be quite effective for moderate outside temps — getting the temperature inside the van almost down to outside ambient.
September 18, 2014, June 24, 2015, July 1, 2016