Air conditioner efficiency

[TomG2]

I recently purchased a new travel trailer and deliberately went with a non-ducted AC this time. It is working great in 100+degree heat. My thinking was to avoid the long runs of ducts in the ceiling where the maximum heat gain is likely. Does anyone know if it actually makes a difference in efficiency? I use a small fan to spread the cool air around and aid in circulation.

[pnichols]

We have ducted A/C in our 24 foot motorhome.

Maybe it's due to the short ducting runs in our small rig such that they don't lose much heat along the way, but .... the air coming out of the ducts feels real cold. I can't imagine it being any colder coming directly out of the air conditioning blower itself. We even have to close or redirect some of the ducts because the air feels so cold when blowing directly on us from the ducts.

[otrfun]

We have a 32 ft. 5th wheel with very high ceilings and camp when temps are as high as 115-118 degrees. We have a 13.5k a/c in the front, a 15k unit in the main living area. In ducted mode, no cooling problems with higher humidity and temps up to 90-95 degrees in the south/southeast. However, in the desert SW with temps around 115-118 degrees we were forced to "completely" bypass the ducting with the 15k unit. We blocked off the ducting ports, removed the sliding ceiling baffle, and allowed all the cold air to exit straight down---pretty significant increase in cooling . . . and, unfortunately, a bit noisier, too.

[TomG2]

Do non-ducted units need or benefit much from the internal sealing often mentioned for the ducted models?

[tragusa3]

If your concern is "electric savings"? Probably no one cares. The electric is paid for one way or the other. Even if it wasn't, taking a wild guess, I bet the difference associated with ducting is less than 50 cents a day.

I didn't realize they were still producing non-ducted trailers in something 25' and larger.

[ScottG]

Like many, I've had both over the years.
I think a lot more of the "cold" makes it into the cabin with a non-duscted unit.
But with the length of bigger RV's a non-ducted unit just wouldn't spread the AC around enough.

[shastagary]

check out the things in this post ac duct work i also sealed the ducts at the last vents in each run using a piece of cardboard taped with foil tape in a u shape at the last vent. one duct continued 4' past the vent it really increased the air flow on my system.

[red31]

The SEER has nothing to do with ducting.

[TomG2]

I realize that there are dozens of variables between RV's. My question is, will the electric savings be noticeable between a non-ducted and ducted AC in a basic 8 X 25 box on wheels? One, two, ten percent? Maybe nobody really knows. Or cares.

[j-d]

I believe non-ducted offers the possibility of better cooling efficiency. As some have said, the floor plan and the way the RVer uses it, has to be right. The way we use our 31-ft no-slide Class C, it works for us. It's also LOUD.

But I think there are other serious variables, specifically, how tight the coach is, how well it's insulated, perhaps dark or light exterior, how well the ducting is done etc. Brother has a 33-ft Cardinal TT that's 30A with one ducted A/C and it cools very well.

[TomG2]

I guess I don't know how to ask a question. I understand the benefits of ducting. I have had ducted AC in some of my trailers and fifth wheel trailer. I am curious as to whether the amount of heat gain from the ceiling ducts matters when it comes to cooling a travel trailer with no partitions. I also know that non-ducted is noisier. It just seems like this trailer gets a lot cooler a lot quicker than my last two which had ducted AC. Might be all in my imagination, but recent 100 degree days have not been a problem.

[tragusa3]

I like having both options. We dump it to get a jump start and then switch it over. Couldn't live without the ducts with our layout. Kids bunks would be hot as well as master bedroom.

[Johno02]

Ours are ducted, with a "chill grill" that can be opened. When very hot out, open both grilles and use a good fan to circulate the cool.

[TomG2]

I have no doubt about the value of ducts in cooling remote areas. I am only thinking of the efficiency in cooling an open area approximately 8 X 25. I know the first air to come out of the ducts was always very warm.

[time2roll]

Old-Biscuit wrote:
I have best of both.......
Ducted (cold air comes out farthest away from AC Unit) and a 'chill grill' which I can open and DUMP majority of discharge plenum straight down into kitchen/living area.

Mine also and it definitely cools better in the non-ducted position.

Ducting is less noise. Probably the ducting is leaking quite a bit into the ceiling cavity but I have not been brave enough to pull it all apart to fix it. If I remove an electrical cover plate there is cool air coming out of the wall... one guess where that comes from.