Custom RV Vent Fan Project
Summary: Custom roof vent fan created that is very quiet and very low power, and also works on vents that do not have a crank to open/close the vent (but rather has the pull open/closed levers). Sound and power analysis is down at the bottom.
I wanted to add some vent fans to some of my RVs. Specifically, I wanted to add fans above the bed in the rear of the RV. I love bringing in cool air at night and while sleeping, especially when camping in the summer heat when it finally cools down in the evening. The ceiling vents on one of my RVs doesnโt have a crank handle, but instead has one of these push/pull leversโฆ
So that seemed to eliminate the possibility of many of the full vent sized fans (ie. Hengโs Vortex, MaxxAir, etc) without doing perhaps more work than I wanted to do to redo the vent.
I also had two other criteria that I really wanted to see if I could achieveโฆ Quiet and Low Power.
I decided to build my own fan solution just to see if I could do it (โฆI enjoy these type of projects). After researching quiet, low power, 12v fans, I landed on this oneโฆ
https://www.amazon.com/gp/product/B08QDMV4X6/
$12.37 on Amazon. It is actually a fan made to cool computers. Airflow: 72.8 CFM/123.76 mยณ/h (@ 1700 RPM), Noise Level: 0.3 Sone (@ 1700 RPM). Very quiet. For each vent, I put two of these together.
To connect them, I got some ยฝโ aluminum angle bar from Home Depot and drilled some holes in the appropriate places to attach the fans (Cost ~$2.50 for this setup length needed). I painted them glossy white on the underneath visible sideโฆ
https://www.homedepot.com/p/Everbilt-1-2-in-x-96-in-Aluminum-Angle-Bar-with-1-20-in-Thick-802677/204273980
I wanted to have a nice clean finish, and I had some white gloss Rustoleum spraypaint already so I spray painted the bolt headsโฆ
(I drilled a bunch of little holes to โholdโ all the screws upright while I spray painted them)
Then I put two fans togetherโฆ
Here is the top side of the fan assembly (unpainted because you cannot see it from inside the RV) next to a Hengโs Vortex I had laying around.
Here is what it will sort of look like when installed in the non-crank vent (screen not put back on yet)โฆ
I decided to put it on one of my other RVs first (one that does have a crank to open/close the vent)โฆ
From thisโฆ
To thisโฆ
I was lucky to find power right at the vent when I took off the trim, so that made wiring it up easy. I added a switch ($4) to turn it on/off:
When I was installing everything, I damaged the screenโฆand it is a bit dirty. So I ordered a new one and new white trim as long as Iโm at it. Should be able to install those in a few days once they arrive.
So how does it work, sound, and how much power does it use?? I tested/compared 3 fans that are in this RV.
Fan #1: Not sure the brand, but it is like a Hengโs Vortex, or MaxxAir, or Fantastic Fan.
Fan #2: Your standard bathroom 6โ propeller fan.
Fan #3: My custom designed fan.
Fan #1:
Fan #2:
Fan #3:
Noise Test:
Fan #1: (it has 3 speeds) Low: 23dB, Medium: 26.8dB, High: 28.8dB
Fan #2: (bathroom fan): 30.7dB
Fan #3: (my custom fan): 10.4dB (Very quiet)
Power Test: (via a battery monitor)
Fan #1: Low: 1.08a, Medium: 1.44a, High: 1.88a (it has 3 speeds)
Fan #2: (bathroom fan): 1.2a
Fan #3: (my custom fan): 0.25a (4 times less than the big fan on Low speed)
Air Flow test:
Fan #1: Only blows out (not reversible): Seems to move a tremendous amount of air. I read somewhere for similar types of full vent fans blowing ~170cfm.
Fan #2: (bathroom fan): Only blows out: 6โ fan. Couldnโt find the CFM spec.
Fan #3: (my custom fan): The ad description says 72.8cfm per fan. So two fans might be 145cfm(?). It does blow a decent amount, but I feel like it is a fair amount less than the full vent Fantastic Fan type.
Summary: My total cost was ~$40 for the parts. It was pretty easy to put together and to install. Iโm VERY happy with how quiet it is and how little power it consumes considering I will likely leave this on overnight while sleeping. It also will allow me to add fans to the vents that do not have the vent cranks on them (so a Vortex or Fantastic Fan or MaxxAir would not work). I especially think Iโll be adding these over the rear beds of my other 2 RVs since they are so quiet. I have solar on all my RVs, so while the RV is in storage I might just leave the fan running (0.25amp x ~12hr of darkness = 3AH from my battery bank) pulling in fresh air (I have a vent cover over this vent so I can keep it open even if it is raining or while driving).
Stay breezy!
Chris
San Jose, CA
Own two 2015 Thor Majestic 28a Class C RVs