Actually, if USAians used as many watts per person as Costa Rica(8x fewer - 1683 wpp vs 207 wpp[1]), our renewable infrastructure would be able to support us entirely(currently 13% of total generation)[2], and infact we would have power to spare.
Yes, but here in Costa Rica we do not need to spend energy warming our buildings in winter. Many businesses use air conditioner in the warmer zones, though. For example, in Guanacaste and Puntarenas.
[1] http://en.wikipedia.org/wiki/List_of_countries_by_electricit...
[2] http://www.eia.gov/tools/faqs/faq.cfm?id=427&t=3