Keeping Cool in our Lil Box on Wheels

Skip 500 · 09-20-2018, 05:38 PM

Aside from having the rotten egg smell water on our trip, we have found that our 13.5K Coleman Mach 3 AC does not do a very good job of keeping is cool. Especially when it hits 110 degrees. Will a 15K unit do a better job? Would changing to a lower profile unit increase the CFM? It seems that part of the issue is that not much air comes out of the ceiling vents even when I close the 2 main vents on the ceiling unit. What have others done?

The Gritz Carlton · 09-20-2018, 05:51 PM

Someone will point you to the 50 page thread on all the mods done lately to turn it into an ice maker. Lots of options!! You'll be fine!!

TurnerFam · 09-20-2018, 05:54 PM

everyone has different ideas of what 'keeping us cool' means - as this topic comes up almost daily, during the summer, for all sorts of types and sizes of RVs and motorhomes - whether a single AC unit, or multiple ones.

How you 'feel', inside your 'tiny box' during 110degree temps, sitting exposed to the sun, and many with added humidity, will certainly NOT feel good, even with the AC full blast... it's doubtful that any change in size/style is going to radically change that.

An easy check, though, is your ducting, if you have any. Sometimes the factories don't do a good job of providing a clear, unobstructed, line to the outlets. Remove your cover and see what's 'up in thar!'...

Also, electric fans used around the coach go a LONG way toward air movement, which can be just as important as the 'temp' of the AC unit's output, itself.

Some days just ain't gonna be fun... : /

WSPhil · 09-20-2018, 05:55 PM

First, I don't think any MH is built to keep comfortable in extreme heat or cold. But I have read where people have checked ducts and found that they weren't attached to the a/c or had debris blocking them. Of course, it also helps to keep shades down, close off areas you're not using and run fans. We did go to 1 campground this summer where nothing helped (full PM sun on big front window) but we were able to move to a shady site. If not for that we would just have had to go hang out elsewhere for a few hours.

Skip 500 · 09-20-2018, 06:02 PM

Quote:

Originally Posted by The Gritz Carlton

Someone will point you to the 50 page thread on all the mods done lately to turn it into an ice maker. Lots of options!! You'll be fine!!

I hope someone can send me that link,

I am terrible with the search function

. I did not mean to

Laco · 09-20-2018, 06:17 PM

At 110 degrees, its going to be difficult to make anything very cool, especially an RV, with paper thin walls, and virtually no insulation. We added a second AC to our Gemini, which does help. At 95 degrees, I can now hold the inside to about 71, not sure about 110, though.

JamieGeek · 09-20-2018, 06:22 PM

Quote:

Originally Posted by Skip 500

I hope someone can send me that link,

I am terrible with the search function

. I did not mean to

I think he means this one:
http://www.thorforums.com/forums/f27...ice-12980.html

The Gritz Carlton · 09-20-2018, 06:30 PM

Bingo...thanks Jamie!!

Skip 500 · 09-20-2018, 06:37 PM

Quote:

Originally Posted by JamieGeek

I think he means this one:
http://www.thorforums.com/forums/f27...ice-12980.html

Thank You Jamie

Bob Denman · 09-20-2018, 06:56 PM

Post this picture on the wall. It'll help to "set the proper mood"...

Oh! Good luck with finding the solution that works best for you!

http://www.thorforums.com/forums/att...1&d=1537469780

brucev · 09-20-2018, 07:26 PM

I think the problem is probably the lack of insulation and large windows in the Motorhome rather than the AC, I used to have a 20' hi-lo that was insulated very well and had an awning over the large front window and the Coleman in it would keep it down to 60 degrees in mid 90 degree temps. Long story short, insulate everything you can and maybe consider window awnings on the exterior of large windows. Good luck and safe travels.

Beau388 · 09-20-2018, 07:44 PM

We always travel with the temps at or better than 100 degrees in the summer. It is south Texas, after all. It is difficult to cool down a coach in the full sun at high ambient temps. The dash air plus the Coleman Mach 15 A/C does a good job in keeping the entire coach at about 78 degrees, which is where we set the thermostat. We usually stop about 5 pm when the temps are in the low 100s. We, then, rely on the Mach 15 and the Coleman Mach 8 heat pump to maintain the 78 degrees. If we are going to be stationary for a couple days, I hang the Magne Shade. We always figure on running the generator anytime we are traveling, heat pump in the winter and A/C in the rest of the year. We have averaged 265 hours per year on the generator. This has been a completely trouble free coach for three years.

The Gritz Carlton · 09-20-2018, 08:22 PM

i think Skip just has a few adjustments to make with the aid of the A/C thread above. We've had great success with both A/C's and the dash unit does excellent job while underway. When your glasses fog up when you go outside, it's a good sign they are working well.

Brad2018 · 09-20-2018, 08:43 PM

I read most of the 50+ page thread. I also have the 13.5 unit. Yesterday at this time with no AC on my temp was 110 inside. Today with the AC on it is 75. I had it set to 77.

I really only did three things to see a good improvement.

1. I first replaced the thermostat with Coleman Mach digital.

2. Then removed the four vent covers on each end, and sprayed the expandable foam sealant to stop the air from blowing past the last vents. (stick washcloths in the ends first to make sure all of the vents get air!) Once the sealant dries I shaped it with a knife. Even with the two main vents open I still get some air through all of the other vents now. When the two mains are closed I get a lot more air through all of the vents.

3. Removed the main cover and found that one of the ducts that diverts the air fwd and aft was not installed properly. It was about two inches forward of where it should be. I was losing air flow to the vent at the bed. So some air was blowing into lost space. I used HVAC tape to really seal up the ducts. This also reduced the amount of noise a good bit!

mstng · 09-21-2018, 03:24 AM

My thinking is that the ducts have limited value in a Thor made coach. By the time the cold air reaches the vents the temp has risen due to lack of adequate insulation in the roof. I came to this conclusion after doing what many have done. My baffle separating cold from warm was leaking and not sealed and the the end of the vents are not terminated properly. I fixed all that and had improvement but for me the biggest improvement was adding an oversize vent addition below the blower. Simple, and now I can cool the front quickly and turn the vent to the rear when needed. I'm happy in florida where it's been unbearably hot the last few days with "real feel" temps at 105...I am now able to actually set the thermostat in the bedroom and it will finally cycle on and off when it gets too cold at 3 in the afternoon.

Long & Winding road · 09-21-2018, 09:53 PM

Skip 500, One of the best things you can to (and its cheap) is get the reflective bubble stiff in your front windshield and the DS and PS windows in the cockpit area. That is the largest sourse of "inbound" heat. I tinted my windows in the front - so that helped a lot.

It comes in large roll from like HD or Lowes stores - Cut to fit. I have ones cut for every window in my RV - that way I can black it out if desired inside or reject heat on one side so I can look out the other side and enjoy the views.

Also try the other tips above and search some treads on this awesome site.

carlgorski · 09-22-2018, 07:28 AM

Check cold/hot air baffle. Tape any gaps. Check cold air out and tape gaps. If possible go on roof and insulate a/c unit.

Dippytwo · 09-22-2018, 11:37 AM

I use Magne Shade on the front and side cockpit windows. That has helped a lot. A cheaper option is the reflective stuff that Long & Winding Road said. I do use that when my MH is in storage to help keep the sun out and to keep it from getting to hot inside. I cut it to fit snug to the windows.

Bob Denman · 09-22-2018, 12:50 PM

And during storage: that stuff should also help to keep "curious eyes"; from getting a nefarious view inside...

**16ACE27** · 09-22-2018, 02:13 PM

Reflectix is great stuff to keep the heat out.
https://www.lowes.com/pd/Reflectix-1...5-ft-L/3011906

I've used it in RVs for decades.

Cutting a piece to size is OK for smaller windows but in my ACE my rear escape window and DS living area windows are larger so I got a sheet of coroplast that was camouflage on one side from Lowes, cut it to size for the large windows and glued reflectix to it. We rarely remove the rear window panel and the livinf area window panel slides behind the sliding bedroom door when not in use.

Another major help is installing a curtain track behind the cab:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Get some thermal drape panels:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Sew some tracks to them:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

And use them to block off the cab area either when stationary to help keep the coach cool (even with curtains/panels on the winshield/side windows a lot of heat still comes in the cab) or to help keep the cab cool while traveling without passengers.

You may also like: