I have a 700ft hill between work and home. Going to work is a nice easy ride. Don't worry about breaking a sweat, I do change my clothes once I get to the office. (When I went to the office)
The ride home is more challenging. I like to say I can't make it up the hill alone, and neither can my bike, but together we can.
I have a fitness watch and I find my heart rate is elevated for the entire ride to work and back. So I know I'm burning more calories then driving. I'd burn more for sure if I turned off the motor, but I enjoy the ride with it on.