The gurus at Building Science have updated their conditioned attic recommendations for every climate. If there is one code requirement that should be implemented immediately, this is it.
And for those roofers and shingle salesmen who always say "It will void the shingle warranty", attic ventilation has very little effect on shingle temperature.
Conditioned attics are now finally allowed in the IRC building code, which Denver uses, but they should be mandatory. They can be accomplished at little to no cost, because they eliminate the often tricky attic ventilation requirements.