| Author |
Message |
Pat Bartlett (Muddog16)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 6:39 am: | |
I've researched roof tops, split units, until i'm blue in the face, I've read many posts mentioning basement units, ok now i need to have input on those pro's and con's, also if you know or have a basement unit what are your impressions of its preformance. And finally any information you might have on who makes or sells these basement units. I just need to cover all of my bases before i decide which way to go, as always thanks for the great stories, and coments. Keep up the good work TwoDogs! |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 7:13 am: | |
With the basement a/c...you MUST have a way to get rid of massive amounts of heat...on a/c you don't cool the air...you subtract the heat...THEN...you have to find a way to get rid of the heat...do ya' feel like leaving a couple of bay doors off ?? I suggest roof air,but, you are a big boy,you make your decision |
John that newguy
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 7:47 am: | |
I had been trying to decide the same thing. I finally came to
my decision to use roof airs (and the Welch auxiliary system),
thanks to the comments of all those that had posted their
comments here.... and those that have owned the various
systems.
My simple summation:
With Roof air:
Easily replaceable
Let's cooled air drop to the floor and easily exhausts rising hot air.
Less expensive to install
No ductwork to heat or cool before feeling hot or cold.
Low cost
*noisy fan
With split system:
Expensive
More difficult to install
Greater chance of coolant leaks
Difficult to replace
Easy transfer of hot/cold air, but less efficient than roof type.
Uses more power than roof types.
*fan noise
With basement air:
Difficult to replace
Expensive
Difficult to install
Uses more coolant
Uses more power
Must push cooled air to the ceiling and pull hot air down.
Least efficient of other types due to ducting required.
*most quiet.
For under $500 each, with heat strip and exhaust capability,
I'll go with the roof air. |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 9:06 am: | |
JTNG
Add to Roof Airs:
More difficult to service, higher, more vulnerable profile; (Ignore if your planned use is a "pavement queen!")
Observations re split systems:
Expense is worth the interior volume savings
Replacement argument is problematical, nobody (or rarely) replaces the complete system. Component replacement (and incidence of leaks) depends on responsible, quality based, construction practices.
Even a roof air stupidly installed will be difficult to replace.
Your conclusion regarding efficiency is likewise dependant upon responsible, quality based installation, if so, why wouldn't split system mfgs utilize roof top components?
Fan noise, also is based on choice of components and responsible installation.
You makes your choice and pays your price in noise and convenience.
Observations on basement air:
Incorporating the above comments, agreed as to ducting, the only difficulty (IMHO) with basement air is the duct sizing necessary to transport sufficient mass of air - which uses up too much of the most precious commodity of a conversion - volume (of ducts)
If sized properly, the energy used to move the air could be less. Noise comes from accelleration/decelleration of air, which wastes power. Roof airs are noisy. Properly sized basement ducts use too much space.
Would you agree that an intelligently installed basement air could be less problematical than changing a roof air? I'm (politely) wondering if the back problems you've previously mentioned (unless you were kidding and I didn't pick up on that) has colored your opinion on the removal/installation issues of basement equipment?
Finally I understand cold air perfusion of the living space, approached by your "Must push cooled air to the ceiling and pull hot air down." comment can be wisely and efficiently addressed by carefully planning and separating supply and pickup points close to the ceiling but at different points of the living space.
I'm opting for cleaner roofs (since my '80 had it's roof damaged by an Oak branch during delivery on the low-boy) and better use of interior space and will install a split system.
Uses more coolant/power or did you mean requires more coolant/ power?
With regard to the power, since the unit capacity is usually greater than (one of a set of) roofairs, do they actually take more power per BTU cooling capacity or are you addressing peak current flow per installation? You won't run most basement units on 20A.
Quiet depends more on responsible, intelligent installation practices - which typically trade off, inversely, between noise vs expense/volume required.
Onward and Upward |
David Dickens (Debdav)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 11:14 am: | |
Mark and 2D:
I agree with the observations. I am also close to installing 2 basement Coleman units in the H3. They can be installed in the center bay next to the fuel tank. A screened floor and louvered door will permit cooling. The ducting to the ceiling will be through cabinets and rear closet. Return air is through floor and cabinet vents and ducting. The Coleman units each use 2 20A 120VAC circuits that add when more cooling is required. One unit costs 30% more than a 15,000 BTU roof air but provides 22,000 cooling BTU's. Price from Ron the Bus Nut.
Yes, I am a dreamer. But I hope that the finished product is visually appealing and functions well. By mounting the units in the spare bay, I think that service would be easier. Also, if push comes to shove, converting to roof airs down the road can be accopmlished. I am framing for 4 roof airs and running circuits. All is easier when you perform your own conversion. |
Merlin P_V
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 12:37 pm: | |
opinions are like a** holes everyone has one!! so here is mine, I purchased one from ron the busnut and it set in storage for almost 2 years,finally I got to the point of installation, thought I better hook this thing up and see if it really as bad as everyone says they are! turned on the juce and wala! in a fiew moments had 46 degree cold air massive amounts!! exiting the cold air duct and reasonably quiet, so lets try the heat pump side, within a minutes hot air 94 degrees in the plenum chamber, and reasonably quiet, I feel when completely ducted you will not hear any heating or cooling when unit is running and no vibration, no side vents in the coach all vents are underneath cooling air is on left at the outermost edge and exhaust air is on the right directed outboard and don`t seem to interact with each other,will be a lot easier to service than crawling up on the roof!! FWIW. |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 12:52 pm: | |
david...you are pulling your return air off the floor??...where the cold air is...should be pulling it off the ceiling where the hot air is..........yep...everybody has one... |
Gillig-Dan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 2:05 pm: | |
David,
You have probably already thought about this but, be sure you insulate your cooling pipe where it passes through your cabinets so you don't have condensate problems in your closet. The central air in my house did not have insulation around the ducts and I had a lot of problems with water dripping onto the ceiling plaster. I had to inject spray foam in around the duct and repair the damage.
I am in just in the process of installing a basement system in my bus. I am rigging it together from a 30K btu system pulled from a transit van. I decided to run my compressor from an electric motor. I will use a multiple ratio pulley system, like the one on my drill press, to run the system at various loads. That way, I can choose how many amps in/ btu out, I use. With this setup I plan to have an amp draw of about 12 to 25 amps @110vac so I can have better flexabiliy for connecting to various sources like the generator, park power or an extension cord to the house I'm parked in front of. I am currently debating whether to pipe it to the same ducts that my furnace uses by creating a plenum after the furnace and using the furnace fan to push the air, much like a home system uses. It would be better to run the ducts to the ceiling but, since the ducts are floor mounted, they blow up toward the ceiling; good enough for me.
Gillig-Dan |
David Dickens (Debdav)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 4:20 pm: | |
Thanks guys,
Yes I am using insulated duct for the transition from the basement to the ceiling.
I considered the return at the ceiling and may if return duct can also be located in cabinets. I have used ceiling returns in homes for years.
The biggest problem with the underfloor residential type units is the amount of return air to the system. I do not want to freeze the unit up from inadequate airflow. |
Sean Welsh (Sean)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 8:47 pm: | |
Pat,
Not sure I can contribute much to the excellent exposition of pros and cons already presented. I can, however, give you a data point:
Our bus had basement air when we got it. Notwithstanding the comments already made here about "easy serviceablity," I will tell you that, in practice, basement units are next to impossible to service once fully installed. By contrast, roof units are a breeze. In fact, our basement system was so difficult to service and so inefficient that we ripped it out and replaced it with rooftops.
We pulled out waaay more *system* capacity than we needed to replace it. I think the basement units were rated at 20,000 BTU/hr each, and we took four out. We replaced that with three 13,500 BTU/hr roof units, and we seldom run all three at once. Roof units are much more efficient.
We did not want to sacrifice headroom to duct our roof units, so we have "air distribution box" style units. These are, indeed, noisier, but we do not find them excessively so (we have Penguins). However, you can get all of the benefits of roof units without most of the noise simply by ducting the output using the "plenum" style units.
As a bonus, when we went to roof airs, we got a whole bay back for storage.
BTW, I'm not sure what John is referring to when he talks about an exhaust option. None of the roof airs I've used (Dometic and Coleman/Mach) exchanged any air between the inside and the outside of the coach. (AFAIK, neither do the basement units, and certainly not the splits.)
-Sean |
Shel rands5302
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 11:12 pm: | |
Here's my chance to add some tech advise:
Heat/Hot air =
option 1 snowmobile suit,hat and gloves
option 2 call from mother in law
option 3 sexy woman undressing
Air/Cold =
option 1 open windows
option 2 call from mother in law
option 3 undressing
Anything else
Lola |
Rob King
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 11:30 pm: | |
Pat
I am planning on 2 22K basement airs to go in the bays where the bus air came out, one on each side. As noted above they run on 2 20amp circuits. The ducts up will run behind the refer on one side and behind the pantry on the other. We are going to have a mirrored ceiling and the ducts will come up the side and drop the air through grills in the side of the mirrored ceiling recess. Return air will be in the kick space below the cabinets, above the refer, above cabinets, etc. I have a friend that has these in his Eagle and it froze me out in mid-summer in Branson. Also very quiet, no hot/cold spots.
I think we all realize that the installation is the key to basement airs. I have contacted several A/C contractors and have professional advice about duct material/sizing, etc. Roof airs are less particular about installation but there is the noise, however small, to contend with. I believe the posts are right that if you duct the roof airs there would be less noise. I haven't even investigated the split systems because I have heard some horror stories about costs of instillation, replacement parts, repairs that scared me off, maybe a mistake. I personally chose basement because of the finished height of the bus with roof airs would not comfortably fit in my garage, the noise factor, economy without the extra roof drag and the even temps.
I got my new surplus Coleman units from James at Colaw RV, 1-417-548-2125 for $895 each. I know that Ron the Busnut has them as well, I think for the same price. I will look up the Coleman web site which gives you the option to compare cooling effects, electric useage, etc. for both roof and basment. Then you can make an informed decision.
Rob
91 Prevost
Missouri |
John that newguy
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 08, 2005 - 7:37 am: | |
Sean-
Re: "BTW, I'm not sure what John is referring to when he talks
about an exhaust option. "
Our Winnebago had a 1998 Coleman 15kbtu rooftop a/c w/heat
and exhaust fan. The built-in exhaust fan was a powerful unit that
worked only on 110v and was noisy as the air conditioner, since
the speed was the same as the AC running on high and there were
no factory made provisions for a fan speed control.
I may be able to locate the model number someplace among the
records I'd saved from the RV.. If it's among those records..
I gave all of the important paperwork to the buyer..
I did have a problem with the exhaust flapper sticking in the open
position. We'd get very little cooling after switching it to exhaust
and back, and wonder why.. The switch position for exhaust was
between high cool and off, complicating the problem until the
problem was resolved by the RV shop.
So Sean... Yes indeed there was at least one model that had
an exhaust... Can't always find one whilst inside the ivory tower.. |
Sean Welsh (Sean)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 08, 2005 - 12:55 pm: | |
"... Can't always find one whilst inside the ivory tower.."
I see no reason to be snide. I provided information based on my *experience*, which is clearly different from yours.
You listed "...easily exhausts rising hot air" among the benefits of roof-top air conditioners in a way that made it sound like that is a common feature. My *experience* is that it is not common.
The emphasis in these two paragraphs, by the way, is added to directly contradict your suggestion that I live in an ivory tower. I live in a bus.
As long as you've made the suggestion, though, I spent ten minutes or so this morning on the RVP web site doing some "ivory tower"-type research, and it does not appear that an outside exhaust is currently offered as an option on their rooftop units.
-Sean |
Jtng
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 08, 2005 - 1:09 pm: | |
*Yawn* |
niles steckbauer (Niles500)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 08, 2005 - 2:57 pm: | |
Ian - da Faerie is at it again - {:o |
John that leader of the Faerie ring
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 08, 2005 - 3:14 pm: | |
HAR!! |
FAST FRED
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 09, 2005 - 5:49 am: | |
If the RV is being built as a "luxury" home , the concept of noise 24/7 in warm weather from a rooftop carbunkle air cond doesnt make lots of sense.
If the camper is a budget job , done as cheaply as can be , you have to put up with the noise to save some money.
Seems that simple to me,
Do it YOUR way!
FAST FRED |
Sean Welsh (Sean)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 09, 2005 - 1:05 pm: | |
Fred,
I consider my home to be quite luxurious. It's our only home, so the amount of money we spent on creature comforts was really not an issue. Yet we used roof units, for all the reasons I described.
I will also point out that most of the major high-dollar converters are also now using rooftops (e.g. Marathon). For them, it's always been about appearance. Now that they have awning supports that protrude 8" above the roof line, the air conditioners are not visible from the ground, and there are obvious cost, space, and efficiencey advantages. The noise is almost completely mitigated by ducting. Marathons, by the way, start at $800,000 and go up from there.
So your "cheaply as can be" comment just does not hold water.
Furthermore, I am really, really tired of you calling an air conditioner a "carbunkle [sic]." This evokes a particularly putrid mental image, and I don't see how such a medical condition can even remotely be connected to anything on a roof, even the most hideous monstrosity. Which makes me wonder -- do you even know what a real carbuncle is?
-Sean |
ChuckMC9 (Chucks)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 09, 2005 - 1:42 pm: | |
Hee Hee!
Sounds like my whole bus!
One entry found for carbuncle.
Pronunciation: 'kär-"b&[ng]-k&l
Function: noun
2 : a painful local purulent inflammation of the skin and deeper tissues with multiple openings for the discharge of pus and usually necrosis and sloughing of dead tissue
- car·bun·cled /-k&ld/ adjective
- car·bun·cu·lar /kär-'b&[ng]-ky&-l&r/ adjective
http://www.meriam-webster.com/cgi-bin/dictionary?book=Dictionary&va=carbuncle |
H3 (Ace)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 09, 2005 - 4:02 pm: | |
Yep that what "IT" is alright! LOL |
John that newguy
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 09, 2005 - 5:04 pm: | |
Ah-HAH!
It twas a Coleman "Super Mach Exhaust", model #6798.
They no longer make any model that has an exhaust fan capability.
When I mentioned the "exhausting" of the rising hot air, I was
referring how the air conditioner moves the air - In one port
and out the other.. Is there a better way to describe the action?
Don't matter; don't care. |
Buswarrior (Buswarrior)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 10, 2005 - 11:08 pm: | |
Hello
For those who appreciate stock roof lines....
Roof airs do make for a disruption in her sexy shape.
If the roof lines are less important than other considerations, well, the roof is a handy and practical place to put the AC appliances, freeing up other space for other stuff.
Beauty is in the eye of the beholder, as they say, so however you spell it, "carbuncle" does accurately describe roof airs to some in the crowd!! :-)
happy coaching!
buswarrior |
FAST FRED
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 11, 2005 - 5:53 am: | |
"carbuncle" does accurately describe roof airs to some in the crowd!! :-)
All is personal taste ,
I certainly prefer an RV that looks exactly like a stock coach with the great fluted sides , like trains of old.
If folks prefer the "Shoebox" look , flat like a factory RV , that too is their CHOICE!
Beauty is in the eye of the beholder, but comfort and luxury go far beyond that.
The Ears , a lack of noise ,(so no blasting Carbunkles)
the Nose , no old greasy hamburgers hiding in a carpet glued to the overhead,
Touch , its easier to sit on a couch or real seat , than on a slab of wood and some foam stuff,
easier to sleep on a real sprung bed than another plywood slab.
The Eyes , its great to actually SEE out of the coach , rather than exist in a sewer pipe with blocked windows ,
All will be determined by the preferences (and billfold) of the converter.
DIYW,
FAST FRED |
Pat Bartlett (Muddog16)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 23, 2005 - 7:36 pm: | |
I was browsing through this older thread, and just to give a little follow up, here is what i did, the information was awesome from everybody and i do mean everyone had good input, but as always it comes down to what makes me happy. I chose the basement units, for a couple of reasons, i don't like the roof tops no offense to anyone, i know they are quick to repair when needed, split units to me looked really neat, but i have to agree when one breaks it could be costly. the basement unit to me was like working on your home system, and i feel comfortable with that, when i built my home i installed my geothermal system my self, if i can manage that then i think i can handle the basement units. Thanks for the input again! It worked!........Pat |
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