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| Quietest roof A/C Heat Pump [message #242761] |
Sat, 08 March 2014 11:44  |
corleyw
Messages: 130
Registered: June 2007
Location: Battle Ground, WA
Karma: 0
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We have a Dometic roof A/C, that works great. Cools the coach really well, up to about 90-100 degrees outside. It's about 20 years old, and probably not as efficient as some newer units, but it works OK.
My only complaint with this unit is that it is really noisy. The fan makes a huge noise all by itself, but the compressor make the whole coach sort of resonate when it kicks in. (I suppose the roof makes like a big speaker.)
I read somewhere a while back, that typical RV non-ducted roof A/C units put out about 70db of noise, on full blast. The article said that anything above 50db is bad for your ears. I know when ours is running at full blast, we really have to turn up the volume on the TV to hear it, and after that my wife is almost deaf for a few hours...
SO, I was thinking of upgrading to a roof A/C unit with the heat pump function. (The resistive heat strips don't impress me at all.) However, I don't want/need to do this unless there is a unit out there that is much quieter in operation. I put a mini-split heat pump in our beach house, and you can hardly hear it running, when it is putting out tons of heat or cold, so I know the quieter technology is available, maybe just not in the packaging of the typical roof unit.
(In fact, I did some measuring, and the 12k btu mini-split inside unit would fit nicely above the rear window, with outlet air shooting forward down the hall into the living space. The only obstacle there is where to put the outside unit. I suppose it could be repackaged and stuffed into the Onan cabinet, or something, but... Dreaming there...)
I can't seem to locate any noise measurements for the new RV heat pump roof A/C units. Does anyone have any practical knowledge or pointers to actual noise measurements they could provide? I will only replace this unit if I can find a much quieter solution.
Corley
'76 Glenbrook
29 other vehicles
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| Re: Quietest roof A/C Heat Pump [message #242766 is a reply to message #242761] |
Sat, 08 March 2014 12:12  |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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| corleyw wrote on Sat, 08 March 2014 11:44 |
We have a Dometic roof A/C, that works great. Cools the coach really well, up to about 90-100 degrees outside. It's about 20 years old, and probably not as efficient as some newer units, but it works OK.
My only complaint with this unit is that it is really noisy. The fan makes a huge noise all by itself, but the compressor make the whole coach sort of resonate when it kicks in. (I suppose the roof makes like a big speaker.)
I read somewhere a while back, that typical RV non-ducted roof A/C units put out about 70db of noise, on full blast. The article said that anything above 50db is bad for your ears. I know when ours is running at full blast, we really have to turn up the volume on the TV to hear it, and after that my wife is almost deaf for a few hours...
SO, I was thinking of upgrading to a roof A/C unit with the heat pump function. (The resistive heat strips don't impress me at all.) However, I don't want/need to do this unless there is a unit out there that is much quieter in operation. I put a mini-split heat pump in our beach house, and you can hardly hear it running, when it is putting out tons of heat or cold, so I know the quieter technology is available, maybe just not in the packaging of the typical roof unit.
(In fact, I did some measuring, and the 12k btu mini-split inside unit would fit nicely above the rear window, with outlet air shooting forward down the hall into the living space. The only obstacle there is where to put the outside unit. I suppose it could be repackaged and stuffed into the Onan cabinet, or something, but... Dreaming there...)
I can't seem to locate any noise measurements for the new RV heat pump roof A/C units. Does anyone have any practical knowledge or pointers to actual noise measurements they could provide? I will only replace this unit if I can find a much quieter solution.
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Somewhere on the internet is a writeup on something about some roof ac units that came installed with something upside down or backwards that made it thump. It can be fixed, but I can't find the writeup.
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| Re: Quietest roof A/C Heat Pump [message #242774 is a reply to message #242766] |
Sat, 08 March 2014 13:11 |
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Richard RV
Messages: 631
Registered: July 2012
Location: Full-timer for 12 years, ...
Karma: -17
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| A Hamilto wrote on Sat, 08 March 2014 11:12 |
| corleyw wrote on Sat, 08 March 2014 11:44 |
We have a Dometic roof A/C, that works great. Cools the coach really well, up to about 90-100 degrees outside. It's about 20 years old, and probably not as efficient as some newer units, but it works OK.
My only complaint with this unit is that it is really noisy. The fan makes a huge noise all by itself, but the compressor make the whole coach sort of resonate when it kicks in. (I suppose the roof makes like a big speaker.)
{snip}
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Somewhere on the internet is a writeup on something about some roof ac units that came installed with something upside down or backwards that made it thump. It can be fixed, but I can't find the writeup.
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I believe that was written up in a relatively recent issue of the GMCMI newsletter and had to do with the mounting bolts being installed upside down as a shortcut to speed up installation. One upside down bolt would make contact with the compressor during start up and make a banging noise.
Since Corley's A/C is a replacement I'd tend to doubt that was the culprit, but it or something similar might be contributing to the noise and is worth investigating.
Richard
'77 Birchaven TZE...777;
'76 Palm Beach under construction;
‘76 Edgemont waiting its turn
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| Re: [GMCnet] Quietest roof A/C Heat Pump [message #242781 is a reply to message #242761] |
Sat, 08 March 2014 15:04 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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I have the heat pump version. It's as noisy as the one it replaced. Also, the heat pump is suited to taking the chiill off on brisk mornings. Below about 40 degrees, it is not efficient, so there's a 'stat in the unit which shuts it off. Great for fall and spring, winter time you need a furnace.
==johnny
________________________________
From: Corley Wooldridge <corley@corleyw.com>
To: gmclist@temp.gmcnet.org
Sent: Saturday, March 8, 2014 12:44 PM
Subject: [GMCnet] Quietest roof A/C Heat Pump
We have a Dometic roof A/C, that works great. Cools the coach really well, up to about 90-100 degrees outside. It's about 20 years old, and probably not as efficient as some newer units, but it works OK.
My only complaint with this unit is that it is really noisy. The fan makes a huge noise all by itself, but the compressor make the whole coach sort of resonate when it kicks in. (I suppose the roof makes like a big speaker.)
I read somewhere a while back, that typical RV non-ducted roof A/C units put out about 70db of noise, on full blast. The article said that anything above 50db is bad for your ears. I know when ours is running at full blast, we really have to turn up the volume on the TV to hear it, and after that my wife is almost deaf for a few hours...
SO, I was thinking of upgrading to a roof A/C unit with the heat pump function. (The resistive heat strips don't impress me at all.) However, I don't want/need to do this unless there is a unit out there that is much quieter in operation. I put a mini-split heat pump in our beach house, and you can hardly hear it running, when it is putting out tons of heat or cold, so I know the quieter technology is available, maybe just not in the packaging of the typical roof unit.
(In fact, I did some measuring, and the 12k btu mini-split inside unit would fit nicely above the rear window, with outlet air shooting forward down the hall into the living space. The only obstacle there is where to put the outside unit. I suppose it could be repackaged and stuffed into the Onan cabinet, or something, but... Dreaming there...)
I can't seem to locate any noise measurements for the new RV heat pump roof A/C units. Does anyone have any practical knowledge or pointers to actual noise measurements they could provide? I will only replace this unit if I can find a much quieter solution.
--
Corley
'76 Glenbrook
29 other vehicles
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Quietest roof A/C Heat Pump [message #242782 is a reply to message #242761] |
Sat, 08 March 2014 15:12 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| corleyw wrote on Sat, 08 March 2014 12:44 |
We have a Dometic roof A/C, that works great. Cools the coach really well, up to about 90-100 degrees outside. It's about 20 years old, and probably not as efficient as some newer units, but it works OK.
My only complaint with this unit is that it is really noisy. The fan makes a huge noise all by itself, but the compressor make the whole coach sort of resonate when it kicks in. (I suppose the roof makes like a big speaker.)
I read somewhere a while back, that typical RV non-ducted roof A/C units put out about 70db of noise, on full blast. The article said that anything above 50db is bad for your ears. I know when ours is running at full blast, we really have to turn up the volume on the TV to hear it, and after that my wife is almost deaf for a few hours...
SO, I was thinking of upgrading to a roof A/C unit with the heat pump function. (The resistive heat strips don't impress me at all.) However, I don't want/need to do this unless there is a unit out there that is much quieter in operation. I put a mini-split heat pump in our beach house, and you can hardly hear it running, when it is putting out tons of heat or cold, so I know the quieter technology is available, maybe just not in the packaging of the typical roof unit.
(In fact, I did some measuring, and the 12k btu mini-split inside unit would fit nicely above the rear window, with outlet air shooting forward down the hall into the living space. The only obstacle there is where to put the outside unit. I suppose it could be repackaged and stuffed into the Onan cabinet, or something, but... Dreaming there...)
I can't seem to locate any noise measurements for the new RV heat pump roof A/C units. Does anyone have any practical knowledge or pointers to actual noise measurements they could provide? I will only replace this unit if I can find a much quieter solution.
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Corley,
I hate to disappoint you, but most of the noise is from the inside fan and ducting (such as it is). It is related to the velocity of the air that must be moved for that amount of cooling. My real new Carrier is not a lot quieter than the Coleman MarkIV I took off, but it is 5 inches shorter so I can get into my barn.
Keep on thinking, it is the most cost effective thing you can do.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Quietest roof A/C Heat Pump [message #242801 is a reply to message #242784] |
Sat, 08 March 2014 18:34 |
corleyw
Messages: 130
Registered: June 2007
Location: Battle Ground, WA
Karma: 0
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Senior Member |
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I spoke with a guy that has an Atwood unit, and he indicated that it was a bit quieter, but still pretty loud, especially on high fan speed. Looking at the Atwood chart confirms what he said, and also the 70db figure I found somewhere else for other units.
I'd really like something quieter than even the Atwood...
Corley
'76 Glenbrook
29 other vehicles
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| Re: Quietest roof A/C Heat Pump [message #242802 is a reply to message #242761] |
Sat, 08 March 2014 18:36 |
Chr$
Messages: 2690
Registered: January 2004
Location: Scottsdale, AZ
Karma: 1
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In My experience, Carrier units. Low profiles specifically, but the are OOP. You will also find it quieter if you duct it, but that means you build ducting in your GMC ceiling. Makes a huge difference. If I ever do an AC uint in a coach again, I will use a Mitusbishi MR slim and mount the outdoor unit on the rear bumper...
-Chr$: Perpetual SmartAss
Scottsdale, AZ
77 Ex-Kingsley 455 SOLD!
2010 Nomad 24 Ft TT 390W PV W/MPPT, EV4010 and custom cargo door.
Photosite: Chrisc GMC:"It has Begun" TT: "The Other Woman"
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| Re: Quietest roof A/C Heat Pump [message #242804 is a reply to message #242761] |
Sat, 08 March 2014 18:45 |
Chr$
Messages: 2690
Registered: January 2004
Location: Scottsdale, AZ
Karma: 1
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Senior Member |
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The Attwoods seem to be something new, never seen them before. They also upped the HP threshold to 16K and 18K.
My carrier is a 15K heat pump and I use it in AZ, but when the weather gets too cold outside, the noisy gas furnace kicks in automatically, usually not till 5 AM, and wakes us up, and then we are rested enough that we cannot go back to sleep. I may decouple them by connecting my furnace to a different Thermostat.
Also, the Carrier wireless remote control sets off my smoke detector... Fun, huh.
The quality and technology of Air conditioning in the USA is abysmal. We are so far behind the rest of the world in cooling just because of an entrenched industry which controls everything including the ineptitude of the HVAC "Technicians" in the industry. Oh, that motor has more than two wires? there is no relay or cap to blindly swap? Oh. Shrug.
Finally, an inverter driven compressor has returned to the market in the Westinghouse units for residential use. Not since the Trane EV1500 could we get a large home-unit that had this design, as the technicians couldn't service them.
I'm sure this is waaaay more than you were asking, but RV AC units suck, are horribly built, and noisy. At least the Carriers and Colemans have dual fan motors so the indoor fan can be on low and the outdoor fan on high for max heat transfer.
I'm working on a completely new type of system for RV's. wait a few years, and I'll sell all of you one.
-Chr$: Perpetual SmartAss
Scottsdale, AZ
77 Ex-Kingsley 455 SOLD!
2010 Nomad 24 Ft TT 390W PV W/MPPT, EV4010 and custom cargo door.
Photosite: Chrisc GMC:"It has Begun" TT: "The Other Woman"
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| Re: [GMCnet] Quietest roof A/C Heat Pump [message #242815 is a reply to message #242807] |
Sat, 08 March 2014 19:30 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Espen,
If you like you can use the name of my GMC in the USA for your second GMC.
But please spell it in Norwegian so people don't get confused! :-)
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Espen Heitmann
Sent: Sunday, March 09, 2014 12:06 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Quietest roof A/C Heat Pump
I was seriously thinking about buying the Atwood, it is a pretty new construction and you can get it complete for around $700
But tonight I bought the second GMC in Norway so it will have to wait :d
--
1973 26' Parrot green Seqouia in Norway
"Loffen" translates to white bread, it is also a nick name for your.. well you know..down there.. and it was my dog's name, but hey
you can also call me Espen ;)
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Quietest roof A/C Heat Pump [message #242819 is a reply to message #242804] |
Sat, 08 March 2014 19:53 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Chris,
IMO the 16K and 18K is suspect; on the front page of the brochure it states;
"OFFERING 16K OR 18K EQUIVALENT PERFORMANCE"
On the second page the Specifications state:
BTU (Equivalence)* AC-135 = 16,000 AC-150 = 18,000
*Equivalence/information based on actual testing via ARI Standard 210.
Note what is noted in the manual for these units:
http://www.atwoodmobile.com/manuals/ac/MPD%2015000%20AC_IOM_04-16-12.pdf
This is what Camping World notes:
http://www.campingworld.com/shopping/item/atwood-air-command-rv-air-conditioner-15k-white-ducted/71791d
I reckon to compare apples to apples you need to the other 13,500 and 15,000 BTU units via the ARI Standard 210 and see what they
put out.
I agree with you vis-à-vis air conditioning in the USA is behind the rest of the world. Here in Australia most homes use split type
units for each room so you can turn individual rooms on / of and regulate the temperature in them as well.
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Chris Choffat
The Attwoods seem to be something new, never seen them before. They also upped the HP threshold to 16K and 18K.
My carrier is a 15K heat pump and I use it in AZ, but when the weather gets too cold outside, the noisy gas furnace kicks in
automatically, usually not till 5 AM, and wakes us up, and then we are rested enough that we cannot go back to sleep. I may
decouple them by connecting my furnace to a different Thermostat.
Also, the Carrier wireless remote control sets off my smoke detector... Fun, huh.
The quality and technology of Air conditioning in the USA is abysmal. We are so far behind the rest of the world in cooling just
because of an entrenched industry which controls everything including the ineptitude of the HVAC "Technicians" in the industry. Oh,
that motor has more than two wires? there is no relay or cap to blindly swap? Oh. Shrug.
Finally, an inverter driven compressor has returned to the market in the Westinghouse units for residential use. Not since the Trane
EV1500 could we get a large home-unit that had this design, as the technicians couldn't service them.
I'm sure this is waaaay more than you were asking, but RV AC units suck, are horribly built, and noisy. At least the Carriers and
Colemans have dual fan motors so the indoor fan can be on low and the outdoor fan on high for max heat transfer.
I'm working on a completely new type of system for RV's. wait a few years, and I'll sell all of you one.
Chr$
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: Quietest roof A/C Heat Pump [message #242828 is a reply to message #242761] |
Sat, 08 March 2014 21:11 |
quadracerx1
Messages: 207
Registered: April 2013
Location: Puyallup, Washington
Karma: 1
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Senior Member |
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I was looking at the Gree AC units... Although they are low profile or at least it looks that way... I'm not sure how loud they are...
While on the subject of Roof AC how difficult is it to wire a second unit in? I only have one and since I have my ceiling out for the most part, now would be the time to wire it. Even if I don't use it, the wiring will be there.
Do I need a separate circuit? Anyone have a diagram?
Thanks..
Steve
75 26' GMC Glenbrook
Puyallup, Washington
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| Re: Quietest roof A/C Heat Pump [message #242853 is a reply to message #242761] |
Sun, 09 March 2014 07:22 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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There was a guy at Branson who had one of these and I noticed it during the open house tour of his 23' coach. He was very pleased. Don't recall his name but he was a retired airport manager, average height/weight and didn't have a lot of hair.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: Quietest roof A/C Heat Pump [message #242859 is a reply to message #242853] |
Sun, 09 March 2014 08:07 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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Steve, See if you can find Avion AC wiring diagram. Avion wired the rear coach A/C separate from other A/C circuits. They are all 40 amp service, unless converted along the way.
Since ceiling is down, I would put a separate AC line to the rear vent. I would also run additional 12 v lines along the sides for future use, even if none is planned for the present.
When my ceiling comes down this Summer, I will add several separate 12 v lines and maybe some 110 AC lines. And, coax lines for ham radio, plus additional tv cable to finish a proper tv installation. Just my thoughts.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] Quietest roof A/C Heat Pump [message #242861 is a reply to message #242859] |
Sun, 09 March 2014 08:20 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Steve,
Here you go:
http://www.gmcmhphotos.com/photos/random-photos/p46646-avion-120-vac1.html
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Thomas Phipps
Steve, See if you can find Avion AC wiring diagram. Avion wired the rear coach A/C separate from other A/C circuits. They are all
40 amp service, unless converted along the way.
Since ceiling is down, I would put a separate AC line to the rear vent. I would also run additional 12 v lines along the sides for
future use, even if none is planned for the present.
When my ceiling comes down this Summer, I will add several separate 12 v lines and maybe some 110 AC lines. And, coax lines for
ham radio, plus additional tv cable to finish a proper tv installation. Just my thoughts.
Tom,
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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