Once we have exceeded the volt's battery range of 27 to 39 miles, the onboard gasoline powered "range extender" activates and at that point heating the vehicle becomes free due to the waste heat from the engine. On many trips I will turn the heat down very low until the point at which the engine comes on in order to conserve energy and extend the electric range of the vehicle.
As we edge into colder weather I will be leaving the vehicle out in the sun unless a snowstorm is imminent. On very cold days, or very hot ones, we can use the remote control from up to 100 feet away to activate the climate control system in the vehicle for 10 minutes while it is still plugged in to our charging station. The advantage of this is that we are not draining the battery to pre-warm, or pre-cool the vehicle interior since it is using "shore power".
These strategies can be applied to any vehicle to reduce the requirement for air-conditioning in the summer. For instance when parking in a public parking lot in the summer I always look for the shadiest spot to reduce the need for energy hogging air-conditioning.