I saw an earlier thread from April 2014 on this, but could not find it through search. I was interested in a post by Luke Porter on 4/17 that said the black shroud was 31% less efficient and raised the output temperature by 7 degrees. I believe it, but would like to know where he got that technical data. My new 2014 Sun Valley 26' has a black Coleman Mach 3 unit with a black shroud, and it just is not able to keep up. We are on an extended trip, about 9 weeks so far, and when the outside temperature is over 90, it just can't cool down the trailer. Our previous unit was a 2009 23' Rockwood with a Dometic 13,500 unit, and we camped in Texas in August when it was 107 outside, and it stayed comfortable inside. Both units were 13,500 BTU capacity. I realize this unit is longer, but at least by manufacturer's claim has a higher r-value insulation.I know that the unit is not cooling outside air, and I know that the condenser coils are fan cooled, but the black shroud is much hotter than the white one, so the unit can not be as efficient. I'm hinking of upgrading to a Mach 15 with a white shroud. Not sure if the 1500 btu gain is worth the money, and the cfm spec per Coleman is 325 vs. 320 for our current unit. Big price for a little difference in specs, but I need to do something.Would I be better off just buying a white shroud? If that would give me a 30% increase in efficiency, that's more than the 11% capacity increase by going to the Mach 15. any thoughts?

$120 for white shroud$590 for 15K btu unit

Shroud threadThat was an easy one. Advanced Search keyword=shroud, Message Author=Luke Porter

I'm sorry to hear that your A/C is not working correctly, and there are many things that can affect the performance of your A/C unit, but the color of the shroud is not one of them.

I'm not sure where Luke got those figures, but they don't sound reasonable. An easy way to negate the effects of a black shroud would be to line the inside of the shroud with a reflictix type insulation- a radiant barrier.

One post with no citation or evidence does not convince me the shroud color makes a difference that large.

Black vs. White A/c shrouds | Good Sam Community

KenNTennessee
Explorer
Jul 14, 2014
Thanks for the ideas. I forgot to say that it is a ducted system. I've also seen enough forum posts that I know inadequate cooling is not uncommon.

Sorry, haddy1, I'm not interested in your 100% fuel saving device...

When I get home, I'll do some scientific experiments and measure the results with shroud off, black, white, lined with a radiant barrier and see what happens. Those are all affordable things to try. If none help, I'll consider the 15,000 BTU 325 CFM unit upgrade.
BobR
Explorer
Jul 13, 2014
Take the shroud off and see if the cooling improves.
haddy1
Explorer
Jul 13, 2014
The color of the shroud is NOT going to make any difference.

However, I have a device that fits around your fuel line that is guaranteed to increase your mileage by 100% or more. I would be willing to part with it if you are interested.:-)
wa8yxm
Explorer III
Jul 13, 2014
Old-Biscuit wrote:
$120 for white shroud
$590 for 15K btu unit

Five bucks for a can of white spray paint.
cpaulsen
Explorer
Jul 13, 2014
Chris Bryant wrote:
I'm not sure where Luke got those figures, but they don't sound reasonable. An easy way to negate the effects of a black shroud would be to line the inside of the shroud with a reflictix type insulation- a radiant barrier.

I did this with my white shroud....seemed to make a difference or maybe just what I think it did!!
KenNTennessee
Explorer
Jul 13, 2014
When it is hot, the unit never cycles off, it runs continuously and can not keep up. I have cleaned the filter and checked the coils, they do not look dirty. I have an infrared thermometer that I used to check the air temperature and the unit is putting out 38 degree air when the outside temp was 98, so it seems to be cooling, just does not have the capacity? I took the inside cover off and it does not appear there are any leaks between the return and output air systems. When I gt home, I'm thinking of removing the shroud and painting it white. The other items on the roof that are visible from the ground (roof vents) are white, so I don't think a white shroud will look bad. I agree with the statement about the quality of installation has much to do with the effectiveness of the R-19 ceiling & floor insulation and the R-9 wall insulation. A sloppy job can negate the insulation's value. No way to check that except maybe an infrared camera. Anyway, I would like to know the source of the data in the April post.
adayjk
Explorer
Jul 13, 2014
I also agree that the internet physics is not the best way to diagnose this. If you want the $20 way to test it, buy a drop cloth, and a few cans of white spray paint. Duplicolor has nice plastic rated paint. Climb up there and cover everything up and paint it white. Don't get paint on the condenser fins.

Does the unit cycle the AC compressor, or does it run forever? Is there stratified cold air on your floor?

Depending on humidity, temp, and other heat loading concerns inside your unit you are at the max for the ac unit. My guess is that your new unit is leaking out the cold air. Since cold air sinks, I'm taking a wild guess that there are leaks near the floor down low. On my RV there was a natural passthrough behind the inverter that meant that my outside storage was colder than the house. On some units the furnace return duct also causes a similar problem.

New units "R" values are all good, but they are values based on the quality and quantity of the insulation allegedly used . There is no guarantee that a unit that advertises R100 would not leak like an open screen door from the way it is built.
wrgrs50s
Explorer
Jul 12, 2014
You dont say if it's a ducted or non ducted system.

Take the inside cover off to see if the blower and return air are sealed off from each other where they cannot mix. If any cold air is making it over to the return side, it will not properly function. Even though the air feels cold, it will not pressurize properly and will not distribute the cold air as it should.

It's not likely that the outside cover is your problem.
Ductape
Explorer
Jul 12, 2014
One post with no citation or evidence does not convince me the shroud color makes a difference that large.
Chris_Bryant
Explorer II
Jul 12, 2014
I'm not sure where Luke got those figures, but they don't sound reasonable. An easy way to negate the effects of a black shroud would be to line the inside of the shroud with a reflictix type insulation- a radiant barrier.