Prius Winter Heat question..

[wetcat007]

I've always been curious how does the Toyota Prius's heater work when the gas engine is not running, or does it keep the gas engine running when you have the heat on? Also for AC is it able to run off of battery power or does that need the engine on?

 

[Don Vito Corleone]

According to this Prius owner's site:

Minimal use is the key. Using the Heater or the A/C (which includes the defroster) on anything but a low setting may prevent the engine from shutting off. That will reduce MPG. So, try to avoid high demand use.

Technically, though:

The air conditioner is driven by an electric motor, instead of an accessory belt. This system includes an electric water pump that circulates warm coolant for the heater, allowing the Prius to blow warm air when the gas engine isn't running.