ATO AterraXL composite flatbed camper (pagoda roof)

rruff

Explorer
Curious of R-value with honeycomb construction vs. high density XPS?

High density XPS is is not commonly available, but the stuff you typically buy has a thermal conductivity of ~.034 W/m-K... and the value for light foam hardly changes with density anyway. High density PVC or PU foam is about the same as XPS.

Numbers for PP honeycomb that I was able to find in a quick search ranged from .10 to .12, so a factor of 3 to 4 less resistance, but because of the nature of this material the resistance isn't proportional to thickness, and they don't say what thickness was measured.
 

trackhead

Adventurer
Thanks ^^^ So this rig probably has 2" walls.

I found this from another poster here:
Extruded Polystyrene (blue foam)(XPS) has an R Value of 5-5.4 per 1" thickness
Polyurethane (yellow foam)(PU) has an R value of 6 per 1" thickness. Compare to the XPS it will break down sooner (15-20 years) but can handle chemicals better (like polyester resin)
PP Honeycomb has an R value of ~ 2.5- 3.5 per 1" thickness
 

rruff

Explorer
PP Honeycomb has an R value of ~ 2.5- 3.5 per 1" thickness

Everyone I've seen who sells this material advertises R < 2/in. Because the cells are quite large and extend all the way through, air circulates inside them from inner to outer wall, which is the primary heat transfer mechanism... which means adding thickness doesn't get you very much. I haven't seen any details from ATO regarding the panels, but I'd be surprised if they were 2" thick.
 

mk216v

Der Chef der Fahrzeuge
What I was told by Mario at ATO;
"The walls with their coating inside and out are 5/8” thick with R-4. The floor is 1-1/8” thick R-6. The tapered and flat parts of the roof are 9/16” thick with additional insulation yielding R-8. The key to cold weather comfort in this shell is minimal thermal bridges and the 12600 btu Truma Vario heater."

Not that this changes things much, but keep in mind that my camper is only 1 of 2 ver1 campers; Mario's prototype #001 (mine is technically #002, but 1st production) is the other ver1.
Ver2 campers which recv'd 2-3" higher side walls but their panels should all be the same thickness as mine/Mario's.

It's no TC/OEV panel construction, however on the plus side it is lighter in weight than those. I consider my AterraXL as an easy 3+ season camper. It's doable in winter with blackout blinds shut, even when temps are in the teenF's, just know that you'll be going thru a lot more propane.
 

RAM5500 CAMPERTHING

OG Portal Member #183
I find all of this discussion over panel thickness, R value of insulation, etc... comical...

It matters exactly nothing whatsoever, with all the heat loss and heat intrusion through all the dang windows (and door)...

I did my windows one by one as i was using my camper, and with each one i added, the difference in the insulation factor changed dramatically

The End
 
Last edited:

Victorian

Approved Vendor : Total Composites
I find all of this discussion over panel thickness, R value of insulation, etc... comical...

It matters exactly nothing whatsoever, with all the heat loss and heat intrusion through all the dang windows (and door)...

I did my windows one by one as i was using my camper, and with each one i added, the difference in the insulation factor changed dramatically

The End

100% agreed. As soon as you ad doors/ hatches/windows everything changes. That is why we only going to install one window in our camper going to the North Pole.
The biggest difference in thermal efficiency makes a skylight. Most are just single pane like the max fans etc. Especially in the summer time when the sun beats on it, they act like a greenhouse. In my personal campers, I always rethink it several times if I REALLY need a skylight. Most times I install just because I like the build in LED lights.
 

calameda

Member
100% agreed. As soon as you ad doors/ hatches/windows everything changes. That is why we only going to install one window in our camper going to the North Pole.
The biggest difference in thermal efficiency makes a skylight. Most are just single pane like the max fans etc. Especially in the summer time when the sun beats on it, they act like a greenhouse. In my personal campers, I always rethink it several times if I REALLY need a skylight. Most times I install just because I like the build in LED lights.

Andreas, have you thought about offering reflective and insulated coverings for the Tern windows you sell?
 

RAM5500 CAMPERTHING

OG Portal Member #183
True that. They have no bulk insulation and the reflective side is directed exterior. Which is fine in summer I guess, but in winter you'd want coverings reflecting inward.

No, in the summer, mine radiates heat off of the white frames inside like a radiator. It’s super bizarre
 

calameda

Member
No, in the summer, mine radiates heat off of the white frames inside like a radiator. It’s super bizarre

Huh. the bulk of the frame is external to the reflective surface, so maybe heat is scattered outward, including onto the frame? maybe?

Anyway, a standalone insulated reflective and reversible cover would be boss.

Does Arctic Tern monitor this forum?
 

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