You can minimize this, by turning down the temperature, and by running it intermittently; only when you need it.
The heated seats and steering wheel use a couple of hundred watts, at most. The heater uses a couple of thousand watts, at least.
If the Bolt had a direct heating windshield defroster (like the e-Golf has), then that would be great. These work a lot like the rear defroster, but you can barely see it in the glass.