Spray foam: open cell vs. closed cell?

My energy bills went through the roof this winter and I have decided to have spray foam installed to help. My wife and I have gotten mixed messages about whether or not open cell spray foam is better than closed cell and vice versa. We have cathedral ceilings and I think there are currently some fiberglass batts in the cavities. Any help would be appreciated.
-Tommy D., Santa Fe, New Mexico

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This question is becoming a classic debate in the spray foam world. The R value of closed cell spray foam insulation is higher than that of open cell, meaning you would need less to achieve the same degree of thermal protection. Open cell can allow air and moisture to pass through whereas closed cell does not. Which of these scenarios is preferable will depend on a number of factors such as your climate zone (e.g. hot, hot and humid, etc), and the location of the insulation (e.g. attic, walls, crawlspace, etc). I'd consult with a local spray foam insulation contractor to see which is best for your application.
-Aaron S., Austin, TX