Not to sound dramatic, but condensation in a campervan is basically the kiss of death.
It makes the interior feel swampy, damp, and unpleasant, and it can lead to mold, rot, rust, and all kinds of other problems that are expensive and difficult to repair.
However, there’s a simple way to avoid the blight of condensation: installing a roof vent fan!
In this comprehensive guide, we’ll share some of our favorite vent fan models as well as a buyer’s guide, installation tips, and much more.
- At A Glance: Top 3 Van Roof Vents
- Is A Roof Vent Essential in Camper Conversions & RVs?
- How Do Van Roof Vents Work?
- Do Van Roof Vents Stop Condensation?
- Van Roof Vent Buyer’s Guide
- Roof Vent Accessories
- How To Install a Roof Vent in Your Camper
- Roof Vent Installation Tips
- The Best Roof Vents for Vans Reviewed
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At A Glance: Top 3 Van Roof Vents
This fan from Dometic is a perfect entry level fan – it will do the job very well, but it won’t cost you an arm and a leg.
It has reversible airflow and three speeds to keep your camper comfortable and free of condensation.
No bells and whistles, but you can use it in ceiling fan mode with the lid closed.
This fan is truly deluxe. If you want every imaginable fan feature, this is the fan for you.
It has 10 speeds, reversible airflow, a thermostat, a motorized lid, a rain shield, and a remote.
It can operate under nearly any weather conditions, and you won’t have to lift a finger to operate it. Well, just one finger to press the button on the remote…
This is an expensive option, but it truly has everything you need and more. If you’ll be traveling in wet areas and need maximum ventilation, a rain shield is a must.
The Fiamma Turbo Vent is something of a middle ground option. It has a reversible motor with 3 air intake speeds and 2 air outtake speeds.
You can set the thermostat to have the fan come on and off automatically to keep your camper cool, or you can control it manually if you wish.
Is A Roof Vent Essential in Camper Conversions & RVs?
In short, if you want to be comfortable and safe in your camper conversion or RV, then yes, a roof vent fan is essential.
Having lived in a campervan both before and after installing a roof vent fan, we can tell you firsthand what a significant difference it makes.
There are three main benefits of a roof vent fan. First, it helps immensely to keep the interior of the campervan cool on hot days.
It’s not as amazing as an air conditioner, but it’s much cheaper and uses way less power to maintain a comfortable internal temperature.
You can crack a window or door and turn the fan on to create a draft of cool air – a major lifesaver on those still, hot days with no wind and no relief from the heat.
Alternatively, you can install a second fan to create the same draft effect. This is a great option for stealth van ventilation if you are staying in a city setting and don’t want to leave a door or window open.
Second, a vent fan will help keep your camper or RV smelling pleasant and fresh by venting away cooking smells, steam, wet dog smell, unwashed person smell, etc.
It can also quickly funnel away any smoke or dangerous fumes like carbon monoxide or propane that might be generated by cooking in a small enclosed space.
Third, a vent fan plays an essential role in avoiding condensation and all the problems that come along with that, like mold, rust, rot, dampness, mildew, and so on.
Keeping the air moving can do wonders to reduce the humidity inside and prevent condensation, especially in the winter.
How Do Van Roof Vents Work?
There are a few different types of roof vents, including simple hatches that open and allow air to flow, non-electric fans that are powered by the breeze, and electric 12V fans that can provide better airflow.
In this article, we are looking specifically at electric fans since they are the most popular and the most effective.
A 12V vent fan will need to be connected to your house batteries as a power source and, obviously, installed in the roof of your campervan.
There are many different types of fans, but some can turn in both directions, either blowing cool air in or sucking hot air out.
They have solid covers that can be closed while driving and keep the rain out, although some fans come with rain shields that allow you to operate the fan even while it’s raining – that’s extra helpful for avoiding condensation.
Do Van Roof Vents Stop Condensation?
A roof vent likely won’t eliminate condensation entirely, but it will help dramatically. Condensation forms most often when warm, moist air in your camper comes into contact with cold surfaces like the walls, windows, or ceiling.
The moisture in the warm air is released, forming small droplets on the colder surfaces.
A roof vent fan sucks the warm, damp air out before it has a chance to condense, and it helps keep the interior and exterior temperatures similar.
The air movement through your camper can also evaporate any small amounts of condensation that do form before it can cause damage.
Since hot air rises, a vent fan is a better way to release the humidity than just opening a window.
Condensation isn’t much of a problem in warm climates unless the overall humidity is extremely high, but it can be a real problem in cooler and wetter climates.
Many other techniques can be used in conjunction with a roof vent fan to eliminate condensation, but if you just do one thing, it should definitely be to install a vent fan!
Van Roof Vent Buyer’s Guide
Now let’s look at some of the considerations to keep in mind when selecting the right roof vent fan for your campervan.
Most roof vent fans are designed to fit in openings that measure 14 x 14 inches, although some require 13 x 14 or 14.25 x 14.25.
If you are replacing or upgrading an existing fan, it’s important to match the size exactly to prevent leaks and other issues.
But, if you install a fan where there wasn’t one before (such as in a DIY camper van conversion), the exact size won’t matter too much.
Just make sure the opening and the whole fan mechanism will fit between roof ribs and any other equipment you have or might add to your roof, like solar panels, a deck, a cargo box, etc.
All electric roof vent fans make some noise when in operation, but some models are much noisier than others.
Some models have 10 speeds, so the higher the fan’s speed, the louder and higher-pitched the sound will be.
However, fans generally create a soothing white noise that’s not too annoying regardless of the decibel level.
Sealing your roof vent properly is critical to avoid leaks when it rains.
As such, you want to use high-quality material to seal it. Place strips of butyl tape between the fan frame and the top surface of your van or camper, and then once you’ve screwed it in place, cover the seam and the screw heads with more butyl tape or a bead of liquid sealant.
In some cases, you might not have a perfectly flat surface for installation thanks to the contour of the OEM roof, but you can fill the gaps with layers of butyl tape or another watertight substance.
Some roof vents, particularly the larger sizes, are fitted by screwing through the frame of the vent into the van’s roof.
The holes are simple enough to seal with the above method but it’s worth bearing in mind that they are another opportunity for water ingress.
Fortunately, 12V fans use relatively little power – usually less than 5 amps even on the highest speeds.
Compared to other appliances, this is a pretty low draw. If you are replacing an existing fan, be sure not to exceed the power draw of the original fan by much.
Fan Motor Speed
Some vent fans have 10 or more speeds, while the budget options have fewer.
Different fans can also move different volumes of air, which is measured in cubic feet per minute or CFM.
A high-quality roof vent fan should be able to move somewhere in the neighborhood of 900 CFM.
Some simple fans can only suck the air out of your camper, but the fancier versions have reversible functions, so they can either suck the air out or pull air in.
While a one-way fan is likely sufficient and will do a fine job of keeping condensation down, it is sometimes nice to have the reversible function, allowing you to move air around in the camper and use the fan without having to have the lid open.
That way, if your fan does not have a rain guard, you can close the lid and set it to move air around, which will still help against condensation.
Roof Vent Features
There are a couple of extra features that aren’t strictly necessary, but they can be super convenient:
Rain shields are plastic pieces that fit over the top of the roof vent fan and prevent any rain from getting in while still allowing full functionality of the fan.
They are kind of bulky and therefore require advance planning to make sure your entire fan assemblage won’t interfere with solar panels or other rooftop accessories.
But, if you plan to spend a lot of time in wet climates, they are almost essential – a rain shield allows you to safely vent your camper while cooking even in a rainstorm and avoid pesky condensation.
As an alternative to a rain shield, some fans have a built-in rain sensor that will automatically close the fan lid when it detects moisture, protecting the fan from damage and keeping the interior of your camper dry.
This can be a great low-profile alternative if a rain cover takes up too much space on your roof, and it can give you peace of mind if you want to leave your fan on while you go for a hike and a sudden rain squall pops up.
Some fans can be controlled with a remote, allowing you to change the fan speed, open or close the fan lid, and turn the fan on and off without even getting up.
The remotes are often battery controlled, and they can be super helpful if you can’t easily reach the fan buttons.
For some people, the convenience can be totally worth the few extra bucks it costs to get a remote-controlled fan!
If you select a fan without a remote, you will simply have to press buttons on the underside of the fan to turn it on and off and adjust the speed. The lid may open with a button, or you might have to crank it open manually.
Some fans are equipped with thermostats, which can automatically turn the fan on and off based on the temperature of the camper’s interior.
For example, you can set your fan to turn on any time the camper’s internal temperature exceeds 75 degrees. If the temperature drops below that, the fan will automatically turn off.
This can be a handy feature to keep your camper comfortable without you having to think about turning the fan on and off. It helps ensure that it’s a pleasant temperature when you return from being away from the camper for a few hours.
Roof Vent Accessories
Depending on the fan you select, you may need to purchase additional accessories along with the fan mechanism:
Roof Vent Cover
Some fan upgrade kits are designed to replace older fan mechanisms, so they only come with the actual fan and interior piece.
You will need to purchase a vent cover (the exterior portion) separately for a completely new fan.
Roof Vent Insulator
There are also vent insulators available, which are basically pieces of foam insulation that can reduce heat transfer through your vent fan when you aren’t using it.
These can be helpful to prevent drafts and condensation.
Vent Extension Kit
Roof vents include a vent cover lifting mechanism. It fits into the vent from the van’s interior, through the depth of the vent, insulation and any framing.
Depending on you conversion, it can end up too thick to allow the vent cover lifting mechanism to reach. In this case, you will need to source a vent extension kit from the manufacturers or make an extension piece yourself.
How To Install a Roof Vent in Your Camper
This section will talk specifically about installing a new roof vent fan in a DIY camper conversion.
First step, it’s important to finalize the layout of your camper, including any elements that will be mounted on the roof. This will tell you where the best spot to install your fan is.
Once you’ve found the ideal location, it’s a good idea to make a cardboard template of your fan opening so you can trace it directly on your roof and give yourself a guide for cutting the hole.
You really only get one shot at cutting a giant hole in the roof of your vehicle, so it’s important to double check all your measurements and the placement a few times. Measure twice, cut once, as they say.
If you haven’t already, this is a good time to test your fan and ensure that it actually works – that would be a massive waste of time and energy to get your fan all installed only to discover that the company sent you a lemon or it was somehow damaged in shipping.
And you definitely don’t want a great big hole in your roof while you’re waiting for a replacement.
Line the outline with masking tape to prevent any scratches from tools as you drill and cut – even tiny scratches can eventually rust and cause much bigger problems.
With your outline traced and taped on the roof, you can then drill holes at each of the four corners, ensuring that the holes are large enough to get a jigsaw blade in there.
Use your jigsaw to cut along all of the sides. Remove the tape and finish the hole by filing down the edges until they are completely smooth. Test fit the fan to be sure that it fits in easily.
Next, line the edge of the hole with butyl tape, ensuring there are no gaps where water can work its way in.
Set your fan in place on top of the butyl tape and screw it down, making sure all the wires are where you want them. Then seal the outside with more butyl tape or a liquid sealant, covering the seam and the screws.
After that, attach the wires to a fuse and your 12V power source, and finish the fan with the bottom flange piece.
You may have to cut the flange down to size to fit, depending on the depth of your ceiling.
Some people choose to build their own wooden frame or do another type of finishing work. You may want to wait until you’ve finished the wiring, insulation, and ceiling installation before you put in that last piece.
Roof Vent Installation Tips
Finally, we’ll leave you with a few tips for a successful roof vent fan installation:
Install the Roof Vent Before Insulation on a Conversion
It will be much more difficult to install your fan after you’ve already insulated the ceiling. So, installing the body of the fan should be among the first things you do on conversion vans.
Then you can insulate around the fan and have all your wires squared away before you put in insulation.
Best Places to Position a Roof Vent
Naturally, you want to install your roof vent fan in a spot where it will be most effective and where it won’t interfere with any other elements of your van build.
Generally speaking, the best places to position your fan will be over your kitchen area and/or over your bed.
If you have a shower in your campervan, you’ll want a fan nearby to whisk the steam right out of your van.
Also, keep in mind airflow patterns – if you open windows in the front of the van and have the fan at the back, you can create a breeze that will ventilate the entire space efficiently.
It’s always a good idea to install fuses with any kind of electrical appliance to avoid damaging anything if there’s a short.
12 AWG wiring is usually optimal for powering a 12V roof vent fan, but you can use our wire size calculator to be sure.
Use the Best Sealant Available & Butyl Tape
This is very important, so we’ll say it again – seal the heck out of your vent fan!
Nothing is worse than leaks in your campervan, and it will be totally counterproductive to your efforts to reduce moisture and condensation.
Don’t Install It Backwards!
Be sure you install your fan in the right orientation – the hinged side of the lid should face towards the front of your vehicle.
This is the correct aerodynamic position for any fan and reduces stress on the parts when driving, especially if you accidentally leave the lid open while you drive.
You certainly don’t want your brand new fan to get ripped off as you speed along the highway!
The Best Roof Vents for Vans Reviewed
Let’s look at a few more options for campervan roof vent fans:
Maxxair Vent Fans
Maxxair fans are a long-time favorite for campervan and RV owners. They are durable, high-quality, and quiet to operate. They have many different models, and most come in either ‘smoke’ (gray) or white versions.
This is a simple model with four speeds, a reversible function to move air either in or out, and a manual lid.
It fits openings that are 14 x 14 inches and moves over 900 cubic feet of air per minute (CFM).
This low-profile fan doesn’t have any crazy features, but it is more than sufficient to keep your camper cool and prevent condensation.
The Maxxair MAXXFAN Deluxe, on the other hand, has ALL the bells and whistles – it has a reversible 10-speed fan, a thermostat, an electric lid, a rain shield, and a remote control.
This fan also fits into a 14 x 14-inch hole and moves 900 CFM.
Dometic Vent Fans
Dometic’s FanTastic fans are another popular option, with many different versions and price points.
The FanTastic 1200 Series is the simplest fan that Dometic offers, with three speeds and a one-way motor that pulls air out. It fits in 14 x 14-inch openings and has a manual lid.
A 12-inch fan moves air efficiently, keeping your camper cool and comfortable.
The 1250 is exactly the same as the 1200, except that it offers reversible airflow, so you can use the ceiling fan mode to move air around even with the lid closed.
Stepping up to the 2250, you now have all the features of the 1250 plus automated temperature control through the built-in thermostat.
You can set your desired temperature, and the fan will automatically turn on if the interior temperature exceeds that and turn off when the temperature falls below the setting.
The 3350 includes all the above features plus a rain sensor, so it will automatically close the lid of the fan when the dome gets wet, saving your fan from being damaged and the interior of your camper from getting soaked.
The FanTastic Vent 7350 is the highest-end option, with 7 speeds, a remote control and a wall caddy to hold it, and a motorized vent cover – of course, in addition to all the features of the 3350.
With the 7350, the rain sensor will automatically reopen the lid when the rain has stopped and the sensor dries. This vent does not come with a vent cover, although you can purchase one separately.
Other Brands of Van Roof Vents
Although Maxxair and Dometic essentially dominate the roof vent fan game, some other brands offer solid options:
Fiamma’s Turbo Vent offers 5 fan speeds: 3 speeds for intaking air into the camper and 2 for sucking air out.
The built-in thermostat can be controlled manually or set to run the fan automatically.
Leisure Coachworks makes a great budget option that costs around $130 – a simple Maxxair or FanTastic fan will set you back at least $150, while the higher-end versions can cost more than $600.
This reversible roof vent fan has 6 different speeds and a manual lid. It fits 14 x 14-inch openings.
This vent fan from Hike Crew has 6 speeds, reversible airflow, a rain sensor, a thermostat, an automatic lid, and a remote.
You can also make adjustments on the underside of the fan if the remote is out of reach.
This fan has many of the features of the high-end Dometic and Maxxair fans, although it’s quite a bit less expensive.
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