My Mother in Law bought one for us when we had our first baby. We live in a crap-hole trailer, so it gets very cold in here at night. We kept it in our daughters room and it kept her room comfortable...we were able to put extra comforters on our own bed. I am not sure it would heat a whole large room like a living room...but her little room it did a great job and we didn't notice that much of an increase in the power bills.
Not sure what we will do this year as we have another little person in the house who will be sleeping in our room for now.
:(