I once left my 2007 Prius run all night and only used a gallon if gas. I'm just glad that no one stole it! The battery didn't even use much energy (ICE must have kicked in to keep it charged). Thankfully, no damage and not much gas usage. I had a habit of tapping the power button to turn it off...didn't tap hard enough I guess. Now, not only do I check every time I get out of the car, but I make certaqin to lock the doors and that all of the lights are turned off as well.
FYI, the car is also going to sound a loud beep/whistle if you leave with the key while it's on. I think you'll adapt without even thinking about it, I've had them on 3 different cars now, and it's just not hard to use conveniently.
In my case, I leave my Prius running all night! When car camping in the mountains, I have slept in the car with it running all night on many occasions. My 06 and now my 10 have used very little gas doing this and when weather is not ideal for tents it makes for a very enjoyable nights sleep. I've done this in the wilderness and in campgrounds. Car doesn't make near the noise a generator makes so being close to others is no problem. Vaughn
Sorry, 32, but I was being JUST a bit sarcastic. The "problem" of having three instances where the beeper "didn't work" is better translated: "There were three times I got out of the car, having left it in Ready mode, and walked away somehow oblivious to the three loud beeps it makes each and every time you walk away from the car with the key fob while the car is in Ready mode." To answer your question directly: No, when I park in my garage I don't lock the car. If I got into the habit of locking my car, then I'd have another warning to which I'd also, at times, become oblivious.
If you sleep in it in the car with it in the ready mode, I would suggest getting a CO alarm, just in case, you know, Murphy?
Before I had the Prius, I used to wake up at midnight worried that I left my portable radio in the car and would run to my purse to check. Now I just know I will be running outside in my PJ's making sure I turned the car off. And I street park, so who knows how far away the car will be. I should do what my husband does. When we leave home he takes a picture of the oven so if I wonder if I left the oven on, he can show me the picture. Maybe I should take one of the Prius every night when I park it. Probably cheaper than anxiety meds.
Does not specify whether in ECO mode (maybe not available that model) -- supposed to reduce power to the A/C compressor. Above indicates about 13 per cent power load on the gas engine to run the A/C. Maybe that much improvement in mileage in cool season. Seems similar to loads on other cars. Thermostat temperature setting of automatic climate control could be raised a bit when unattended, then turned down more when occupied. If not automatic, cutting the fan speed back does similar. It would make a lot of difference whether car was in the shade.