Ceiling fan questions

Oh, that makes sense! I was asking up thread about the sort of hood thing that goes on the roof, and I thought u were talking about thst.

We have different impressions of what a shroud is in this scenario.

A fan is round, a window is square, the shroud would fill in the portions outside the round area so that all the air the fan moved could not do a 180 and go back through the fan.

A shroud around the fan makes for 100% air displacement, a simple fan placed in an larger window opening will recycle a significant portion of the air it already moved making it much much less effective at exchanging inside air for outside air.

Think of an Automobile radiator fan, Most enclose the blades in a
round shroud just bigger than the fan blade diameter so that ALL the air the fan pulls, get pulled through the radiator, instead of just a tiny portion of it.

landyacht318 wrote:
Lots of people with homemade class B's say to not locate a ceiling vent over the bed due to inevitable leaks, whether failed sealing or failure to close before a rainstorm.

Oh, dear. I was planning to put my electrical closet not directly under but quite near. I will have to look at that. It's not over the bed, anyway.

Also a fan should be shrouded if placed in a window or vent, otherwise a significant portion of air moved, will be recycled air, whereas a fan with a shroud displaces all the air around it.

That is interesting -- I would have thought it would be the other way round, that the shroud would trap the recently exhausted air.

Lots of people with homemade class B's say to not locate a ceiling vent over the bed due to inevitable leaks, whether failed sealing or failure to close before a rainstorm.

My ceiling vent is located at the peak of my high top, and I tend to cook on a single burner stove directly beneath it.

For Me, efficient 12vDC computer fans with speed control is the way to go. My original 4 inch Nicro marine style mushroom vent could not move enough air on its own, but I can force feed that aperture with powerful enough computer fans to exhange all the volume of air inside once every few minutes if necessary, and I have several ideal for improving airflow using even less electricity, but these are not really required.

Also a fan should be shrouded if placed in a window or vent, otherwise a significant portion of air moved, will be recycled air, whereas a fan with a shroud displaces all the air around it. The key is to exchange inside air for outside air, not just have an interior breeze to cool the skin, but both is better. Exchange inside air for outside air, and blow that cooler outside air across one's skin.

I use powerful Vantec tornado fans 80 and 92MM on a voltage speed controller for interior air circulation, and for white noise when those dang kids have their meltdowns, or the dogs start barking.

beemerphile1 wrote:

Naio wrote:
...without a roof vent I have routinely measured 110 degrees at bed height at 10:30am when it is about 60 outside and sunny.

New van already has a vent hole, which is unfortunately nowhere near the bed. I don't think I want to seal up that one and cut another.

Have a window at the bed? Install a fan in the roof, close all windows except the one by the bed, run the fan on exhaust, and it will pull the outside air thru the window and across the bed.

Yes, that is my plan. I have already installed an open able window by the bed (junkyard, $250 installed). Unfortunately the available window only opens a crack, not enough to accommodate SoundGuy's excellent fan

Naio wrote:
I haven't dealt with rv ceiling fans before, but I guess the new rig will need one.

I'm strapped for cash, and things keep adding up. Are FANtastic really that much better, should I try just a vent and see if I really need a fan?

If lack of cash is an issue but your trailer has a window adjacent to the bed you can achieve the same results for a LOT less $$$ than installing a powered roof vent fan. My own 2014 Coachmen doesn't have a vent over the main cabin so I instead hang this $40 3-speed, reversible fan in front of my street side window. Having had a Fan-tastic vent fan in our previous KZ Spree I can tell you this window fan works just as well. It's a 120 vac fan so when camping without shore power I run it with my inverter.

Naio wrote:
...without a roof vent I have routinely measured 110 degrees at bed height at 10:30am when it is about 60 outside and sunny.

New van already has a vent hole, which is unfortunately nowhere near the bed. I don't think I want to seal up that one and cut another.

Have a window at the bed? Install a fan in the roof, close all windows except the one by the bed, run the fan on exhaust, and it will pull the outside air thru the window and across the bed.

JaxDad, that is way cool!

A buddy who mostly dry camps like me made his own cheapie 'remote'.

He mounted a cheap digital thermostat right next to the fan and then put a NC relay between it and the fan (this also makes the load safe for the stat to handle), the stat is in series with the normal switch.

He sets the 'heat' to whatever temp he wants the fan to go off at as it cools down at night and when it hits that point the relay is energized, opens and shuts off the fan. The next morning as the temp rises back above the set point the fan automatically comes back on.

I had added a ceiling fan to our other 5th wheel for the bedroom.......and just used the remote. Never had any problems.