Monday, March 5, 2018

Fan-Tastic verses Maxxfan Powered RV Vents

I doubt that I’m unique in having both a Fan-Tastic vent fan and a Maxxfan vent fan on top of The Van, but I’ll bet there aren’t all that many such setups out there. What follows, for those choosing between one or the other, is (literally) a side-by-side comparison of the two vents under real-world conditions.

The Players

The exact vents I’m comparing are:

Fan-Tastic Vent: Model 3350 Ceiling Controlled Fan; Three speed reversible fan; Power-lift cover with rain-sensor; Thermostatic control


Maxxfan Deluxe: Model 7000K;Ten speed reversible fan; Power-lift rain-shield cover; Thermostatic control; Remote control


OK, this first section isn’t a comparison of the two vents but rather a comparison of how The Van handles with the Maxxfan compared to the roof-top air-conditioner it replaced.

Writing about his nearly yearlong stay in the International Space Station, Scott Kelly said; I’ve learned that grass smells great and wind feels amazing and rain is a miracle. I will try to remember how magical these things are for the rest of my life.  Well that, the remembering part, is easier said than done and I knew that the first time I drove The Van without the weight of that air-conditioner on the roof was going to make the biggest impression on me, after that I would get used to it and soon start to forget how she used to handle with that burden on top of her, and I was right.

With AC unit
With Maxxair

Of course I was hoping for some improvement in how The Van handled and the first time I drove her out the driveway without the AC unit up there I was paying particular attention, but didn’t really need to. The difference was noticeable enough that I would have perceived it anyway.

It was only 100 pounds taken off the roof, and a few of those added back when I installed the Maxxfan in its place, but the rebound from body-roll, such as when driving diagonally up the entrance to a shop or gas-station, or see-sawing through the washout at the bottom of our driveway, was almost gone entirely. With the AC unit there would be a heavy roll to one side that the suspension would eventually heave back over the other way, but just a little too much so she would roll a little bit to the other side, then back, and finally upright again. With the Maxxfan the initial roll is noticeably reduced, crisper with less wallowing, and she comes back to her feet without any of the extra rebound rolls. She’s also steadier on our often wavy and uneven county roads, staying solidly upright with fewer of the heavy side-to-side rolls she had with the AC up there. I expect the difference was pretty much the same as adding an oversized sway-bar, but for approximately the same price I not only got the improved handling but also the functionality of the Maxxfan.

So, even though I’m going to quickly forget what she was like before the Maxxfan, on the handling front this change has been a definite success.

Keeping the rain out

One highly important feature of roof vents, powered or not, is their ability to keep the rain out.  If they can’t do that then what was the sense in cutting a big frigging hole in the roof?!

With the Fan-Tastic vent keeping the rain out is pretty-much a no-brainer. When it’s closed no rain gets in. And since the rain sensor closes the vent at the first hint of moisture, it’s almost always closed when it rains.

I say almost always closed when it rains because I have experienced two situations where the vent stayed open in the rain. The first wasn’t my fault, the second was.

The first time was an equipment malfunction where the vent failed to notice that it was raining. The fix was relatively painless, with Atwood, who had recently acquired the formerly independent Fan-Tastic Vent Company, honoring the warranty and sending me a whole new vent.

The second time the cover stayed open in the rain, the one that was my fault, came about because the replacement Atwood sent me also came with a slightly different algorithm that decides when it’s time to close, and open, the vent.

After closing due to rain, the original vent would automatically try opening up again later. If the rain had passed the vent would stay open, just like I left it in the first place. The replacement doesn’t do that. Once it closes it stays closed until I come along and toggle the open/closed switch.

That is annoying enough, but the new algorithm, at least the one on my replacement vent, is very sensitive and things like a quick temperature change or a bit of evening dew wafting by will slam the lid closed and keep it that way. In the case of the latter, where the sensor keeps thinking it’s raining, the only way to open the vent again is to kill the power and force the lid open with the hand-knob.

Of course when I do that the vent isn’t able to close itself if any real rain comes along; which it inevitably will. . .

The Maxxfan cover is a little different. Like the Fan-Tastic, when closed no rain is going to get in, but as an added bonus, this is also true when the rain-shield style cover is open; almost always true anyway.

One more note on the Maxxair cover. In the left-hand photo above you can see that the cover extends beyond the rear of the vent but a good strong 6 inches. Because of this I could not put a Maxxair just forward of the solar panel because the cover would then come down right on the panel.

I say the Maxxair almost always keeps the rain out because, while the open cover is 100% effective in normal rains, a hard and/or driven rain can defeat the shielding properties of the open cover.

The photo above was taken after a quick but windy thunderstorm dropped nearly an inch of rain in about 20 minutes on top of the open vent cover. You can see the water droplets that managed to snake their way past the cover and settle on the fan blades. (For some reason droplets don’t seem to collect on the screen though)

So while it’s disappointing to have to remember to close the cover (No auto-close on the Maxxfan) during bad rains the ability to leave the vent open during normal rains makes up for it.

Fortunately, if I forget it’s a relatively small amount of splash-by that comes through and by the time it snakes its way through the cover it has no energy left so any excess falls straight down from the vent. In my case this means it lands on a floor covered with an indoor-outdoor runner over a marine-grade vinyl decking.

Effectiveness as an unpowered vent

The second-most important function of a vent is to – well, vent. Most of the time I use mine as unpowered vents, relying on convection to draw air in through the side window, which is a jalousie-type that I have never had to close in any sort of rain, then up and out the vent.

Because it has a more unrestricted airflow, the Fan-Tastic is better at this than the Maxxair. When the Fan-Tastic cover is open the air flows pretty-much straight up and out.

When the Maxxair cover is open the air flows vertically through the screen and fan, then has to make a 120 degree turn to the rear in order to exit the baffled rain-shield.

Cover color

I wasn’t offered a choice when it came to the color of the Fan-Tastic Vent cover but with the Maxxfan I had my pick of either smoke or white.

Maxxair to the left, Fan-Tastic to the right

During my research I came across reviews mentioning that the smoke cover let in a lot more light than white, the former being described as translucent while the later was more opaque. More light could be a good thing, especially towards the rear of The Van where there are no windows, but I just couldn’t bring myself to put a black vent-cover, which is what ‘smoke’ looks like from the outside, up there on the white roof. Part of that is looks, but it mostly has to do with living in a climate where black absorbs more of the often brutal sun’s heat. So I chose white.

It turns out that the white cover wasn’t as opaque as I expected from the reviews. As you can see in the photo above, which was taken with both covers closed, the white cover of the Maxxfan, there in the background, still lets in some light, though it’s definitely more subdued than what comes through the smoke cover of the Fan-Tastic Vent closest to you. The white cover also creates a much warmer light than the silver-blue that comes through the Fan-Tastic Vent.

So, while the Maxxfan’s white cover doesn’t let as much light through as the smoke might have, I do have more light in the back part of The Van than I did before and that’s a good thing.

One more thing to point out about the covers is that the Fan-Tastic cover (Photo above) uses a single arm on the right side to push the cover open and pull it closed. Under certain wind conditions, this uneven force can create a slight twist as the cover is closing, resulting in a bit of a snap as the cover is snugged down tight. Being supported on only one side, it’s also possible that the cover may be damaged if left up at highway speeds. (I don’t do this so have no first-hand experience to pass along.)

The Maxxair uses an arm on each side of the cover (Photo above) so opening and closing forces are evenly distributed side to side and I’ve never experienced anything other than smooth cover operation regardless of the outside winds. Supposedly the two arms also make it safe to leave the cover up at highway speeds. Again, I don’t do this so can’t say for sure.

By the way, not that it really matters much, but the Maxxair cover opens and closes in less than half the time it takes the Fan-Tastic cover.


Controls on the Fan-Tastic are located on the fan itself and are pretty straight forward. One knob to select off (0) or fan speeds 1, 2, or 3. (Off removes all power from the vent which is how I have managed to defeat the rain sensor a time or two.) Another knob to set the thermostat. (This is used to start the fan when the inside temp gets above the set-point and stop the fan when it drops below the set-point) A rocker switch to change the direction of the fan. ( to suck air out or blow air in) A smaller rocker switch to open or close the lid. And a four-pointed knob for manually opening or closing the lid.

The Maxxfan also has controls located on the vent itself. They call these ceiling controls. (Not shown is a knob in another corner of the vent for manually opening and closing the cover.)

These pressure-sensitive controls are not as intuitive as the ‘ceiling controls’ of the Fan-Tastic vent, so it’s a good thing the Maxxfan also comes with a remote.

From this thing all the capabilities of the Maxxair are easily understood and accessed.

Those capabilities are: cover open or closed; fan on or off; 10 fan speeds from 10% to 100%; fan direction in or out; adjust the ‘set temperature’ up or down; (This is the point where the fan is started or stopped based on interior temperature.) and ‘auto’ mode to use the thermostat set-point to start and stop the fan.

But not all is rose-water and turnips. (Wait. That’s not how the saying goes is it?)

Anyway – the remote comes with a wall-mount holster but I haven’t found the right place to put it yet so the remote actually lives in my drawer for now, and because of this I’m constantly reminded of how big this thing is, there’s more than enough of it to fill my hand. I used to have a camera that came with a remote that had nearly as many functions but was small enough to use as a key-fob. . . Just sayin’.

The remote operates off of infrared, which is line-of-sight, and one reason I haven’t found the right spot to mount the remote-holster is that the remote has to be pointed at the receiver up there on the vent (That shiny little bubble—thingy between the auto and in-out buttons on the ceiling controls two photos ago.) which means everywhere I’ve found to mount the holster requires removing the remote from the holster to point it at the vent anyway.

There are some operational quirks with the Maxxair too.

The Van is a small space and small spaces need plenty of ventilation in order to deal with stale banana-peels and fresh farts, so I tend to leave the vent open unless I’m moving down the road or it’s really cold outside, turning the fan on to assist with ventilation when required. This works just fine with the Fan-Tastic. The cover stays where I put it (within the limitations already mentioned elsewhere) as I turn the fan on and off as much as I like. But with the Maxxair, turning the fan off automatically closes the cover which I then have to re-open by pushing a second button. 

And with the Maxxair there’s no leaving the cover open when in auto mode (Operating off the interior temperature) When the temp rises above the setpoint the cover opens and the fan starts. When the temp drops below the setpoint the fan stops and the cover closes. End of story, no other option, no way Jose.

Personally I’d rather have the cover position and the fan on-off as separate functions.

And while we're on the subject of fans and covers, the Maxxair supposedly has a 'ceiling fan' function, where the cover is closed but the fan is on and blowing inward. I was curious as to how this was supposed to work since the fan is up inside the vent and with the cover closed there's nor real way for air to get up behind the fan to be blown downward. I tried it out and frankly I wasn't impressed. Basically it uses a lot of power, and accompanying noise, to create very little actual airflow. This is one feature I don't see myself using.

Cleaning the screens

Both the Maxxair and the Fan-Tastic have bug-screens that do a pretty good job, (the only defense against no-see-ums is to turn the fan on and blow the tiny little buggers right back out, but then you’re also sucking them in through the window screens at the same time. . .) but eventually both screens are going to need to be cleaned.

The Fan-Tastic screen seems to need cleaning more often than the Maxxair and I attribute this to the cover design, the Fan-Tastic cover allows stuff to fall out of the sky and onto the screen when the cover is open open, which is most the time for me, whereas the design of the Maxxair cover prevents this.

Removing the Fan-Tastic screen to clean it is a grit-chor-teeth-and-hold-yur-breath kind of operation. First you have to grip that little dimple in the photo above with the very tip of a finger and pry down. This, besides hurting your finger, creates a nasty chalk-board type squeal as the first two of eight fixed plastic tabs,

Maxxair screen on left, Fan-Tastic screen on right

some of which are visible on the right side of the photo above, reluctantly release their hold. Then you have to wrestle 6 more of these latches loose before the screen drops, all the while feeling like you are on the verge of breaking the little plastic ring around the screen.

Oh, and then, to reinstall the cleaned screen you have to bend and push and bang until the eight latches squeak and scrape back into place. It takes some force and I’m often half-convinced I’m going to break the ring before I get it back in place.

The ring around the Maxxair screen is not only much heftier, but is held in place with 4 of these turn-locks which makes it much easier to remove and re-install. Turn the four locks and the screen drops right out into my hands. Clean the screen, line up the scolops in the ring with the turn-locks, hold the ring in place with one hand and close the turnlocks with the other. Easy.


The whole point of having a powered vent is to boost the airflow, but nothing in this life is free!

Both the Fan-Tastic and the Maxxair move air. As far as I can tell with just my ears and the backs of my hands (Now that I’m not working for ‘the man’ I no longer have access to the fancy DB meters for sound measurements and manometers with hoods for precise air-flow measurements.) they both move about the same amount of air with the same amount of noise at corosponding speed settings, though the Maxxair, with its 10 speeds as opposed to the Fan-Tastic with three speeds, can also move less air for a whole lot less power, and noise.

What I do have is a way to accurately measure the number of amps each fan uses at each of its speed settings.  Using my ears and the backs of my hands I have determined, as best I could, that Fan-Tastic speed setting 1 is equivalent to Maxxair speed setting 50%, 2 = 80%, and 3 = 100%.

The chart below shows the current-draw for the various speed settings of both fans.

Fan speed
Fan speed







Yep, when I first saw the results I thought I must be underestimating just how much air the Fan-Tastic fan was moving, so I went back and checked everything again, with the same results. With the inaccuracies of my ears and hands, it could be that the Fan-Tastic speed setting of 1 is more like a Maxxair speed setting of 60% rather than 50%, but I don’t think so. But I know for sure that the Maxxair speed setting of 80%, using the same amount of current as the Fan-Tastic speed setting of 1, is actually moving way more air than the Fan-Tastic fan at speed setting 1.

What this chart shows is that the Maxxair moves air more efficiently (Under power anyway) than the Fan-Tastic, using half the current to move about the same amount of air at speed settings 50% & 1 respectively.

Now I have to admit that when I was doing my research into the Maxxair I thought 10 speeds was a little excessive, and frankly, at 10% and even 20% the Maxxair isn’t moving enough air to make much of a difference so I don’t think these lower speeds are very useful. But at 30% the Maxxair is moving enough air to create a very gentle, but noticeable breeze at the window, which is right beside my bed, and does it with delightfully little noise as well as miserly current draw. I’ve never left the Fan-Tastic run all night on speed setting 1 because of the noise as well as current-draw, but I have no qualms about leaving the Maxxair run all night at 30%.

It’s also clear that the Maxxair efficiency (Volume of air to current-draw) starts to fall off rapidly at the higher speeds, making anything above 80% a losing proposition. But then again, before the Maxxair I very rarely ran the Fan-Tastic at its higher speed settings either.

So while the Maxxair has 10 speeds available, I think only the speeds from 30% to 80% are actually useful.


Both the Fan-Tastic and the Maxxair have their own strengths and weaknesses. Fortunately I have one of each on The Van so where one falls short the other picks up the slack. But if I had to choose just one, (These dang things ain’t cheap so having two is a luxury.) it would be the Maxxair for the rain-shield style cover and the slow speed/low current capability.

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