JandM are your in my room with me right now hehe that's pretty much what I do and although not down south we have had frost for the past week. I'm in a very cold house with a room that gets no sun at all and yes I can sleep without the heater on all night.
$600 a month! dam I thought our $300 electric bill last month was bad (thanks to the flat mate who like to warm her clothes in the dryer before she puts them on) but I seriously could not afforded to live in your flat. I'd be the one moaning that I was having to pay for power everyone else was using as I limited myself to try and keep the bill down.