The Volt is a gas-electric hybrid. It will use the gas engine to provide power for that air conditioner or heater.
Selling the Volt as an electric car is just a blatant lie. It is a hybrid, just like the Prius. The only difference is that the Volt can be plugged in to recharge the batteries.
Not exactly. With the volt, you can drive 40 miles on batteries alone. If you drive less than that per charge you never run the engine except when the computer says to to keep it 'happy'. Also, the engine will completely disengage from the drive train in the Volt.