So there has to be an electric heater to deal with that.
Could it have been a two stage design, so that in milder temperatures it could use the heat pump instead of the electric heater? I sure hope so, since that'd really help cool weather AERs here in SoCal. But I think that (along with using waste heat from the motors and transmission) is a Gen II Volt solution. Likewise I wish they'd use a heat exchanger to warm the battery from waste ICE or motor heat, instead of using the electric heater (when possible).
The Gen I Volt is years ahead of anything else out there in the market. And IMHO there are lots of ways to improve it, especially for cool/cold weather AERs. But the first order of the day is to get the thing to market!
C4884 - White Diamond, purchased 10/15/11
It would probably need to work like a house heat pump with electric strips, but I'm sure they looked at it a lot. It might have been better to just use electric heat and save wear and tear on the compressor. Also, there is the added complexity of reversing valves, etc. Without doing any real numbers, I can see where it's a complex scenario. And if it's real cold, the heat pump mode wouldn't serve much purpose.
2013 Volt #D8115
Formerly 2011 Volt #B1514