In response to the Dec. 13 letter from a person whose electric bill exceeded $400 despite solar water and no air conditioning: I wonder if her water heater has electric backup that is always on. If so, during the 16 or so hours of the day when the sun is not heating water, she is using electricity. The solution is either to turn off the electric backup or put it on a timer so it only works a few hours a day at most. The problem with timers is that you must remember to reset them if there is a power outage.
It's also possible that her water heater has a leak or something could be wrong with the solar heating circuit, thus causing the electric backup to run a lot.
The letter writer should have a knowledgeable person do an energy audit to find out what is wrong, either with that or something else in her house.