Just like leaving a light on or computer on, it pulls power. The elements were not on, but the thermostat only denied the power to go to the elements. I blame it on this since it was the only change I made that month? Maybe someone else could give another explanation.
Rakesdl- I have a degree in electrical engineering specializing in power systems, as well as 15 years experience wiring houses, cars, etc.
So if the elements weren't on, then were did it go? In physics, matter (energy) can neither be created nor destroyed. It has to have gone somewhere.
There is no difference between cutting power at a panel breaker, equipment disconnect, or electrically controlled contactor (relay) inside the unit. If no work is being done, no power is being consumed. Unless of course, something is miswired in the unit and something capable of consuming a significant amount of amps is still running. If the heater even had a separate 1kw element that was stuck on 24/7 somehow, it would only cost you $72/mo ($0.10/kWh). I would guess that any more than about 1kw and you would notice the paint burning off it since the fan wasn't running. The 10 KW heater, running for 2 hours straight, 20 days a month at $0.10/kWh, would only cost you $40/mo.
When a light is on, it's on. When it's off, it's off. Period. Leaving a light on is the same as leaving a heater on. You know it because its obviously doing something. A computer can be "sleeping" with the hard-drive spinning while the screen appears black using nearly the power it consumes while you are typing on it (300 watts?), or hibernating with the ram memory still powered (20 watts? I don't really know).
Without knowing how much you used the heater, your electric rate, indoor and outdoor temperatures, and the size, effective insulation levels and air leakage of your garage, it's hard to guess how much power you should really use, and what happened to your power bill. But can assure you with great confidence that your heater could not consume more than $1 to $2 worth of power in month when it's not running (this would be from a 24v thermostat and/or some electronic controls). These are the same type of parasitic or "ghost loads" you hear about from your Utility Co.- your TV, DVD, Laptop charger, Phone chargers, electric toothbrush charger, Printer power supply, Microwave clock, etc.
If this speculation were true,
everything in your house would be consuming hundreds of dollars worth of power each month. An electric range is capable of pulling ~8kw, and it, along with your water heater and dryer by your definition are "hot" 24/7- meaning there is power available all the way up to the relay just a few inches from the heating element. When a control relay opens, no current can flow, no energy is used. period. (again, except for this caveat of a few watts for the electronics). This would be the same for the hair dryer, toaster, hot tub, microwave, clothes iron....
sorry about the huge longwinded post. no one will probably read this far.
So your power bill immediately went back to normal ($???) once you started flipping the breaker?
respectfully,