Does the outside temperature impact when roof work should be done? My Santa Fe style roof needs repair and recoating.
What would be the best energy efficient coating and how long should it last?
Yes the weather and temperatures play a big part on when materials can be installed. Many will list conditions like: may not drop below 50 at night, or have rain scheduled for next X days, etc.
As I left Arizona over 7 years ago, I can't really give you any ideas on what is best but I can tell you that a white coating is generally the best, ceramic is a joke & don't fall for infrared pictures showing the roof being as cool or cooler than the outdoor air.
If you are planning on doing this yourself, stop by a roofing supply house & see what most of the pros are using. If you are hiring out, look for ones that have a good track record, etc.
As for how long it should last, well most have warranties on them but they are worthless if the installer doesn't do the necessary prep, or you don't check to make sure that the scuppers / drains are working properly, etc.
For more information:
Read "Which roof is more energy efficient: a metal roof or an asphalt roof? Also, what are the energy tax credits for roof replacement?" a Q&A answered by Rick Goyette.
Also, read Sean's blog post "Common Sense Building: The Cool Roof Concept."