This will have baseboard electric heat - same as the other half and our house. We heated the west half all last winter, and I did not notice a significant increase in our heating bill. With everything well insulated, it does not take all that much to keep it warm.
The tax assessor came yesterday - it was raining so she did her "look over" from the car, about 50 feet away. Her eyes got a bit big when DH told her my Long Arm was going out there - and then said she may come back when it's all done for another look. Goes to show, you never know when you are going to meet another quilter!