It's installed on an external wall so when you turn the heater 'off', the heat is redirected to outside. They will apparently also reimburse you for energy used.
That's what I mean, off means it's still "burning" but I get no benefit. And according to ihsw the bill is split leaving me with: In winter: Gaining 50% of the power in heat (don't know how that compares heat-wise to natural gas) and in summer, wasting 50% of my own paid-for electricity. I actually doubt if ihsw's comment is true.
The bill is not split -- it says they reimburse you for the measured power usage of the device. Nowhere does it say that this only applies when the heat is being directed into your house, that I could see.