I found that this has been discussed in past years. In my case, It appears that the heat transfer coefficients I see (~500 btu/hr sf °F) are for the internal coefficient only. Shouldn't we also take into account the resistance to heat transfer through the wall and outside of the tank? The fact that my tanks are indoors (no wind, no rain) are what prompted this thread, since the htc for the outside of the tank will be << the condensation coefficient on the inside.
Any thoughts?