I e-mailed Building Science because I wanted to have a clearer idea of what was meant in the book.  This is the response I received from Joe:

"The two metal skins form perfect vapor barriers - one on each side.  In other words we have a double vapor barrier assembly.   Double vapor barriers are never a good idea because if moisture gets into an assembly with a double vapor barrier it rarely is able to get out.  Freezer panels work pretty well because the metal skins have no holes in them - no screw holes for example.  And the joints between panels are airtight because of some pretty sophisticated gaskets.  They work because they are perfectly airtight and vapor tight.  They would make poor exterior wall assemblies because you could not attach any cladding to them.  The cladding attachment would require screws and screws are holes, etc."

chuck07;

First I want to say that I have the utmost respect for Joe as he is genius at mechanical engineering.

However, attached is a cooler/freezer corner connection detail showing screws inside and out, the base, top cap lid and interior clip details also also show screw penetrations for assembly, how else is it held together!
And while steel panels are tight they are not a bio-sphere, they still have windows, doors, exhaust vents, air leakage and once in a while you need to open the door to get in and out.
so now that I have dispelled the theory that there are no holes in freezer panels.

Please see wire lath attached to steel panels at http://southernsips.com/monroebusiness.html

or vinyl siding at
http://southernsips.com/caldwell.html

or fiber cement siding at
http://southernsips.com/groover.html

all of which are attached with screws and all systems are approved to be installed to a steel substrate

So not only can claddings be attached, they are successfuly done.

I can only hang my hat on our success in doing so over the last 17 years and not EVER having a call back for , failures in cladings or for moisture problems.

Chris,

Thanks for your responses.  The comment in the book really caught my attention but the more I think about it I cannot come up with a better alternative than metal sips in Florida (ICF for that matter has two more impermeable surfaces-foam surrounding a more permeable material -concrete).  -As long as leakage (presumably very minor) doesn't compromise the integrity of the metal (rust) or cause delamination from the foam core. 

Have you seen/heard of either of these taking place with metal SIPS?  I have decided OSB skins are too risky in my opinion in Florida.  I guess fiber rock would be okay but appears to be harder to obtain, has handling issues (easy to break) and are more labor/time intensive if doing two stories (one story at a time).  You seem to have the most experience on this site in regard to metal SIPS.  I would be curious to know if you have any lessons learned on things to avoid with metal SIPS.

Thanks again.

chuck07;

Summer  AC temp 72

winter heat temp 70

I did install an ERV 2 years after we moved in, not because of moisture but because of our wood burning fireplace (draft) , even though it had an outside air kit, it still did not have enough supply air.
I usually only run ERV in winter months when humidity is lower and run on a percentage timer 5% of time.
What we have been doing lately is installing a 4" OS air duct (with damper) into return air plenum so  fresh air comes in everytime the HVAC system comes on and gets conditioned thru the unit itself. This also provides positve presure in the home. Damper is usually almost closed letting in minimal OS air.

Metal SIPs lessons learned:

wear gloves when handling - cut edges are sharp
wear sunglasses so you won't go snow-blind

Tip:

glass suction cups are great for making an instant handle when setting walls

Chuck07,

Aluminum or galvanized (G-90) steel skins are usually recommended for coastal use because of the salty air.  G-60 can be used inland.

Alton

Alton;

our old standard was G-90 now we use galvalume

Donaldson;

what are your utility bills, if you can share?