Ducted Air

[time2play]

Huh? Run that by me again?

Originally Posted by ghaynes755

Was just in the first 2015 Classic that was sold up at Gillette. With both AC's running you don't have to shout. It is considerably quieter. A decibel meter might tell a slightly different story so some of this lessening of the jet engine sound of the stand A/C might be the damping and different tonal range of the sound (if that makes sense).

[graysailor]

I think my second question was answered. You can run on 30amps with a adaptor kit? If so that is a good idea. Can't think when I really would need 50amps unless running 2 AC's.

[ghaynes755]

There were previous posts in the thread that a decibel meter had been used and the readings were very similar ducted vs non ducted. What I was trying to say is that the empirical scientific numbers might be correct but the my perception is that the ducted system is much quieter. That perception may be based on the tone of the air from the ducted system. It is a lower pitch than the non ducted.

[Msmoto]

The sound level is highly subjective. However, when using the rear a/c and sitting in my recliner up front, the sound level is not noticeable. Maybe the two a/c units in combination with the ducting makes the units quieter. Whatever it is, IMO, ducted a/c is appreciably less intrusive.

At night, in bed, the decibel meter is around 50, less than human conversation. I do not remember my 2009 Int Ocean Breeze 27 FB ever being this quiet.


Ms Tommie Lauer
Greensboro, NC
2015 Serenity 30 RB / 2008 Dodge Cummins 4 X 4
WBCCI #4165 AIR #31871

[mefly2]

The sound pressure level is empirical with regard to measurements - quantified from the same device at the same location in the same trailer model and length; ducted vs. non-ducted ...go back and look at my comparison numbers; I posted them several times. The higher velocity air from the single exhaust vent produces a higher pitch in the non-ducted system. The ducting reduces the velocity from each of the several outlets and results in a lower pitch. That's my evaluation and perception and I am sticking to it. YMMV

[jkfinephoto]

After fulltiming in my 2015 30ft International I can say that the two ACS with ducting keep it very comfortable in Texas even with the high humidity. I think it's pretty quiet, but I have nothing to compare to... I will say everyone seems to be surprised that it can actually feel cold in here even though the lowest I usually have it set is 78 on auto. And yes, so much for zoning, but I can turn on only one AC at the opposite end at night when it doesn't have to work so hard if it's too loud (though I like the noise for sleeping).

[RVDreamer]

I don't know how many have seen this but I thought I would upload the file so that others could learn more about the new ducted A/C

[Msmoto]

I have now had about three weeks in my new Serenity and can suggest the comfort level of my Airstream is the same as my Allegro Bus, a very sophisticated Moho. In fact in some respects the A/C is better as the diffusion of cooled air is excellent other than the draft on the bed when running on a fan speed other than Lo.




Ms Tommie Lauer
Greensboro, NC
2015 Serenity 30 RB / 2008 Dodge Cummins 4 X 4
WBCCI #4165 AIR #31871

[moosetags]

We have now had the 2015 25FB for a week. We have spent a lot of time in it setting it up. It is still hot and humid in the Florida Panhandle. The new ducted air conditioning works great even though four of the vents have no air coming from them.

It is absolutely significantly quieter than unit that we just traded in our 2012 23FB. I can actually hear the television or radio. We can also hold a normal tone conversation in the trailer while the air conditioner is running.

Brian

[Msmoto]

Four vents with no air….? Are these round or rectangular? The rectangular vents are the return and have a filter behind the grill. The round vents are the cool air supply.

[RVDreamer]

Originally Posted by moosetags

even though four of the vents have no air coming from them.

Moosetags,

Look over the pdf file I uploaded in the post above. It shows a diagram detailing the vents that supply cool air and the vents that are return air.

As Msmoto says, four of the vents are return air.

[moosetags]

Originally Posted by RVDreamer

Moosetags,

Look over the pdf file I uploaded in the post above. It shows a diagram detailing the vents that supply cool air and the vents that are return air.

As Msmoto says, four of the vents are return air.

Thanks much for that info and the diagram. I'll recheck my system in the morning.

Brian

[rodsterinfl]

RVDreamer, thanks for the read. Ever since the "ducted air" hit the forum I have been reading anything I can find about RV air conditioning. I have modified my traditional unit from original and it improved my experience considerably but it is nowhere near the change of a ducted system.

I believe time will tell on the questions raised on this thread. Naturally those that are buying it are in support and hoping for the best. The important thing to remember is that ducted air is not new to the industry. After looking over the Airstream design piece RVDreamer posted, it is really not any different than other systems out there, just applied to an Airstream.

From reading about "basement air" and other threads on "ducted air" I believe that the main reason for the second AC unit follows how many class A owners have described the ducted experience using a non-ducted unit or in some cases closing the duct to cool the space down first, then using the duct to run more continuously. In some setups it is described as having one ducted AC and one non-ducted AC. The noise factor is apparently highly subjective overall. What I found under Class A reads is that owners can turn the fan to low on the ducted model but that cooling ability is greatly reduced and cannot be sustained in warmer temperatures. The idea though is a good one because it provides options.

Oh, and on the basement AC, I read where it was the quietest; however, there were cooling issues that some companies had abandoned the design. This seemed odd to me as tour buses still use it. Still, someone is going to come up with more good ideas for cooling RVs!

[Msmoto]

Oh, more confusion on how the new A/C works…. So far, Zone 1 is in the rear, the actual HVAC unit that is, but seems to blow more air into the front. Also, the Zone 2 Unit, is in the front, but blows more air into the bedroom (rear). Casual observations only. And, some of the round vents do not seem to blow a lot of air, the two over the bed, maybe a bit excessive, although if one likes to sleep with an overhead fan, this is great. More observations on this to be made.

It would seem that if one were willing to give up about 1 1/2" of headroom, a "ducted air" system could be configured from the older A/C units, using sheet metal of other thin material, closed cell foam to dampen the noise, and very thin ducts, roughly 1" in height. Maybe someone will come up with a "kit" to do this on some of the pre 2015 units.

[lewster]

Originally Posted by rodsterinfl

RVDreamer, thanks for the read. Ever since the "ducted air" hit the forum I have been reading anything I can find about RV air conditioning. I have modified my traditional unit from original and it improved my experience considerably but it is nowhere near the change of a ducted system.

I believe time will tell on the questions raised on this thread. Naturally those that are buying it are in support and hoping for the best. The important thing to remember is that ducted air is not new to the industry. After looking over the Airstream design piece RVDreamer posted, it is really not any different than other systems out there, just applied to an Airstream.

From reading about "basement air" and other threads on "ducted air" I believe that the main reason for the second AC unit follows how many class A owners have described the ducted experience using a non-ducted unit or in some cases closing the duct to cool the space down first, then using the duct to run more continuously. In some setups it is described as having one ducted AC and one non-ducted AC. The noise factor is apparently highly subjective overall. What I found under Class A reads is that owners can turn the fan to low on the ducted model but that cooling ability is greatly reduced and cannot be sustained in warmer temperatures. The idea though is a good one because it provides options.

Oh, and on the basement AC, I read where it was the quietest; however, there were cooling issues that some companies had abandoned the design. This seemed odd to me as tour buses still use it. Still, someone is going to come up with more good ideas for cooling RVs!

I the RV industry, RVP Coleman made the 'package' units that were mounted below floor level. Winnebago was the largest used of these units, but they were also used by Damon, Alfa Leisure (now deceased) and several others. Alfa even put them in 5th wheels.

RVP discontinued these units about 3 years ago. They were an incredible PIA to work on as the 300 lb unit had to be dropped to access the interior.

Over the road busses use a different system.....mostly the Cruise Air units that were originally built for yachts. These are bullet-proof units that are totally serviceable while in place, but are hugely expensive.

The RV industry found the disposable roof units to be far easier to install, cheaper to buy and generally better for the bottom line.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357

[moosetags]

Originally Posted by RVDreamer

Moosetags,

Look over the pdf file I uploaded in the post above. It shows a diagram detailing the vents that supply cool air and the vents that are return air.

As Msmoto says, four of the vents are return air.

This morning I got a chance to further assess the air conditioner duct situation in New Lucy. The diagrams you provided helped immensely.

New Lucy is a 25FB. She has two rectangle shaped vents in the ceiling midway in the trailer. I verified that these are the return air vents using a paper towel while the unit is running. Lucy has six additional vents on each side of her interior. Three forward of the air return vents and three aft on each side.

All of the vents seem to blowing air except the three forward vents on the street side. These do not blow any air at all.

Brian

[RVDreamer]

Originally Posted by moosetags

This morning I got a chance to further assess the air conditioner duct situation in New Lucy. The diagrams you provided helped immensely.

New Lucy is a 25FB. She has two rectangle shaped vents in the ceiling midway in the trailer. I verified that these are the return air vents using a paper towel while the unit is running. Lucy has six additional vents on each side of her interior. Three forward of the air return vents and three aft on each side.

All of the vents seem to blowing air except the three forward vents on the street side. These do not blow any air at all.

Brian

I wonder if you have an obstruction in the main duct to the front on the street side. Is it possible to remove a vent cover and use a fish tape to see if there is blockage in the duct?

[RVDreamer]

Originally Posted by Msmoto

And, some of the round vents do not seem to blow a lot of air, the two over the bed, maybe a bit excessive, although if one likes to sleep with an overhead fan, this is great. More observations on this to be made.

Most of this issue is probably just pressure differences in the duct. I would think it would be easy to tune this system by putting folded cardboard obstructions in the ducts at key points.

For example; You could make it harder to blow air to the back bedroom vent by placing a partial obstruction into the main duct to that side.

[Rocinante]

Sounds like you've found your first warranty repair issue on new Lucy. I'll bet they somehow messed up the ductwork. This may not be new tech, but it's new to the AS build teams.

Originally Posted by moosetags

This morning I got a chance to further assess the air conditioner duct situation in New Lucy. The diagrams you provided helped immensely.



New Lucy is a 25FB. She has two rectangle shaped vents in the ceiling midway in the trailer. I verified that these are the return air vents using a paper towel while the unit is running. Lucy has six additional vents on each side of her interior. Three forward of the air return vents and three aft on each side.



All of the vents seem to blowing air except the three forward vents on the street side. These do not blow any air at all.



Brian

[mefly2]

Originally Posted by moosetags

This morning I got a chance to further assess the air conditioner duct situation in New Lucy. The diagrams you provided helped immensely.

New Lucy is a 25FB. She has two rectangle shaped vents in the ceiling midway in the trailer. I verified that these are the return air vents using a paper towel while the unit is running. Lucy has six additional vents on each side of her interior. Three forward of the air return vents and three aft on each side.

All of the vents seem to blowing air except the three forward vents on the street side. These do not blow any air at all.

Brian

Time to see a service tech ... all of our outlets blow cold when on AC and very warm when using heat pump. The rectangular inlets have filter material behind and respond well to light vacuuming.