$500/month seems awfully high for california unless we are talking high desert areas.
and remember, good insulation can bring summer temp down by as much as 15-20 degrees and bring up winter temp by the same amount.
if Montoro and Serenity really did cheap out on the insulation, then I need to revise my analogy: Tiburon would be say an Escalade Hybrid while Montoro/Serenity would be an Yukon.
