range hood ext vent? elec fridge?

[John Z]

I removed the old range hood from my coach today, which was a house hold unit. I will be replacing it with a narrower RV unit that is vented by a 12v fan. What kind of exterior vents have you used to run the exhaust outside? Damn, i am trying to clean up the roof of the bus and i really hate to put another hole into it,,, those things are ugly to me! My original plan was to run it to the large vent for the propane fridge,,, but i would really like to get rid of that too if i can find an efficient fridge to run on either 12v or 120v - any ideas there?

[Nick Badame Refrig/ACC]

Hi John,

I used a refrigerator vent. It worked very well. It's standard in most RV supply houses.

Nick-

You might be able to see it in this picture. Not too noticeable....

[TomC]

I use a Norcold 6.3 cu ft 12v/120v compressor type reefer that I'm very pleased with that requires no outside venting.  I also have the 100lb Norcold chest reefer/freezer for over flow-also a 12v/120v compressor type.  You can hear them running on very quiet nights, but is not very loud at all.
As to the stove vent.  I also did not want to punch a hole in the side, and because of the placement right in between the windows, didn't want to do that.  Instead, I bought a non vented house hold type (120V) hood.  Right over the stove I also have a Fantastic fan.  When cooking, just run the Fantastic Fan on exhaust and run the hood also-works well for me.  Course, we don't fry or cook bacon indoors.  A bit of advice- the 12v hoods are typically loud and don't have much suction power.  Good Luck, TomC

[H3Jim]

I have an over the stove top microwave with a built in vent fan.  It had the option of venting out through the roof or going through a filter and venting forward into the living space.  I had the same problem with coming up with a decent vent, one that I could close off when driving or wanting to stop air circulation, and like you I did not want to cut another hole in the roof or sidewall.

I opted to vent the microwave forward, but I put in a Fantastic fan right in front of the microwave.   It moves so much air it will also pull air directly up from the stove top.  I'm extremely pleased with this arraignment.  Very flexible, totally controllable, and can move more air than an RV hood vent.

[jjrbus]

 If I had heard of this befor I did mine it is the way I would have went. Too late now. Run the vent to the side of the hood and  down through the floor. Ideal setup? No. But better than putting hole in sidewall or roof!  I now have a micro with built in fan. I vent into upper cabinate, which I open and run roof vent.

[boogiethecat]

After a lot of thinking, I finally figured out that a 120 volt fridge with a dedicated sine wave inverter was about the same efficiency and both pieces combined are about half the cost as any of the 12/120 units with Danfoss compressors, plus that opens you to a lot more selection in size etc.  So that's the route I went and I'm happy with it.

For efficient 120 volt refrigerators, I found this nifty webpage that has the ratings of all energy star models made.

http://www.energystar.gov/index.cfm?fuseaction=refrig.display_products_html

The best on on the whole list for the size I wanted (around 10cuft) is the Summit CM115
It is a bit pricey but I found a place in NY that sold it to me for $390 incl. shipping, a fairly good deal I thought
(I think their price went up recently but it's still a good price and they were great to deal with)
http://fotoconnection.com/vi-12121________Summit-CM-115-Dual-.html

Note, even though this fridge uses well less than 200 watts when running, it took a 1KW / 2KW surge sine wave inverter to start the motor.  My 400/800 watt wouldn't touch it.
I'm happy that these days, even big sine units like 1kw can be had for $250 from ebay, and they work well!!

Cheers
Gary

[Barn Owl]

The PO of my bus vented the hood out front and I had always wondered why. I had always thought that was not a good idea but am starting to change my mind after reading the posts. I am so glad to have this BB, it really helps to open my mind to possibilities that I hadn't thought of and the whys behind it. I bet it has saved me from many, many mistakes.

Gary, is that a true sine wave or a modified sine wave?

Thanks,

Laryn

[John Z]

Laryn, i agree completely with you about the value of this list.

I thank each of you for your input. It helps so much to make a decision to have the different points of view. I have decided for the time being to vent my range hood out the refrigerator vent, since they are side by side.

But i do like the idea of going to the high energy electric fridge and inverter set up. It will remove one of the ugly "bumps" from the roof, and also allow me to cover up the fridge burner access door on the side of the bus. Does anyone have a piece of the aluminum bus sideing i can use to patch this area so it blends in? This will also let me run a hot air duct under the fridge from the forced air furnace to the front of the bus.

After switching to the elec fridge and removing and sealing up the old fridge vent, i will vent the range hood toward the front or side or whatever, and rely on a powered roof vent as others have done.

[boogiethecat]

Laryn, it's a true sinewave inverter.  A few things about inverters and motors...
A motor (at least induction motors without brushes, like what's in refrigerator compressors) works by creating a sinusoidal rotating magnetic field, that is " followed" by the motor's rotor.
  If you power the motor with a pure sine wave, it will work with the best efficiency possible. But if you present that motor with a square wave or a modified sine wave, either of which contains lots of energy "outside" of the sine wave's shape, it will still work but all of that "outside" energy will be converted to heat within the motor, not rotational energy, and every last BTU of that heat is wasted energy.  Bottom line is that if you're looking for the longest run time you can get on your set of batteries, or the least possible amount of solar panels, etc, using anything but a pure sine inverter is simply wasting energy.
  Add to that, all of the energy in a square or modified sine inverter that is outside of the sine waveform is in a form called "harmonics" which have a spectrum going all the way up into RF (radio)... and causes many RF based or wireless products to screw up, etc.

Personally I won't own a modified sine inverter for just that reason.  Back when I had a motosat on my bus, turning a modified sine inverter on (but not even loading it) caused the motosat to crap out, interference on my computer monitor, frequent system crashes on the computer, wireless mouse and keyboard to quit, and my GPS to also quit.  Changing to a pure sine eliminated every one of those problems immediately.  Square or modified sine inverters are great for running lightbulbs, universal motors (hair dryers, any electric tools that have brushes in their motors, etc) but as far as I'm concerned, they are never things to build into a bus!  I'm sure many folks use them with good results and they have their place...just not with me!!!!  Am I on a soapbox? Yeah...

[Len Silva]

Just a quick point to make.  Electric refrigerators need ventilation too, and household type refers are meant to be free standing.  If you build one in to a cabinet, make sure you provide plenty of ventilation.  If you mostly use your coach in the hot weather it might be a good idea to continue to vent the refer outside rather than add to the air conditioning load. This would be especially true if the condenser coils are on the rear of the unit without benefit of a fan.

Another point, really a technicality for our use, but venting grease laden air or even the high moisture from steam into the refer vent might be a cause for concern.

Len

[John Z]

Hi Len. I don't follow the thinking that venting moist air out the fridge vent would cause concern. The vent i am talking about is just an open 24" long vent at the edge of the bus roof, with a course mesh screen in it, and covered by a rain cap. It seems to be exactly the same type of vent of those sold for the range hoods.

Also, i guess i need to research the fridge deal some more. Some of them i have read about state the back is sealed and can be mounted right up against a wall. I know the heat has to go somewhere though. I think a much smaller louvered wall vent can handle this, rather than that large ugly roof mounted vent that i have now. Any other ideas or input on this, please share them.

[Len Silva]

John,

My concern was not for the vent but for the fridge. I don't really think grease is a concern for us, we are probably not deep frying in the bus but steam from a pot of pasta or boiling crabs might cause some rust problems with the refer.  Not a big deal, just something to think about.

Len

[John Z]

OK, i getcha. I was going to run a 4" exhaust pipe from the hood right into the fridge vent, so almost 100% of the exhaust should go right out the roof. The prior owner had done a poor job of building an air tight box for the back of the fridge to vent it. So tons of outside air are coming into the bus through both the burner access door and the roof vent. We never knew where all that air was coming from around the micro wave until i started to remove all of it to redo everything. At this point, i feel no matter which way i go, it will wayyyy better than what i had. I hate to think of trying to cool down the bus in the summer with all of that outside air coming in.

[Len Silva]

If you run your 4" all the way up then there should be no problem.  My waste tank vent (2") does the same thing, up behind the refer to the top.

Len