Something that is interesting is that my electric bills provide a graph of my monthly energy usage.
Looking at last year, the BIG bill months are clearly:
July
Aug
Sept
(for air conditioning in the 100 degree AZ high desert)
And:
Dec
Jan
Feb
March
(for heating when temps are in the 30s and 40s).
The heating bills compared to the cooling bills are not really comparable though - the AC uses many, many more watts than heating.
There is also a yearly comparison. I am gratified to see my monthly consumption for 2011-2012 are much, much lower than in 2010-2011. I attribute that purely to insulation. When I was living in the RV there was no insulation. When I rebuilt my back shed, I added as much as i could afford for insulation, knowing the savings would pay off greatly. I even borrowed money from my parents to get extra insualtion.
Living in my shed studio is a far better choice, clearly. If i was to stay in the RV, i would have found a way to insulate that!
For more notes on how I am saving money on keeping things cool inside, this is my thread on 10 Simple Ways to Keep Cool without AC. 
