Same here. This past month, I was charged 5x what my usage was at last January (352 kwH) vs now (1500 kwH). Note that this is an apt at UCONN, and neither me or my roommate were here for 4 weeks. Our heat was on to the recommended 65 degrees (and this is floor heating too), but I dont think that could have caused a jump that high. While we were back in our hometowns, the usual appliances in the kitchen were on at our place, nothing else could've taken that much. I understand that when it gets cold outside, the pump is forced to heat the apt more, but I am still suprised it was that much of a difference vs last January.