We received our electricity 'bill' for the period Nov/Dec/Jan this week and it made me think of this thread. We have a 3kw solar system. Out of interest with the heatwave we have had I thought I would compare this periods bill with the same period last year. We were in credit both periods in both years, although this year we were $16 down from last year in credit. Considering this year we were home more over the Christmas/NY period and with the heatwave, it is swings and roundabouts and we were pleasantly surprised there wasn't really much difference. We have a reverse cycle system that is very effective and we don't really consider the cost, if we are hot we put it on.
We have a ceiling fan only in our bedroom which we find effective and we don't have our air con system running overnight as we can sleep fine, once we are getting ready to go to bed, we switch the air con off. We live in an old (by Aussie standards) double brick house, which we find tends to keep a lot cooler than the modern houses (or cardboard houses as my boss that lives in one refers to them!). Our neighbours live in a new build house the same size as ours and when we go outside we can hear their air con going. We would estimate they have their air con on more than 50% of the time when we don't need ours on.
We have had our windows tinted and have secondary glazing fitted which we find makes a big difference keeping the heat out as well.