Okay heres my question, I can buy a PF-68 for next to nothing from a friend as opposed to spending near $3,000 for a new PF-61 but heres my predicament. I will be using it as a supplement heat the house, would it use way more pellets than say a PF-61 for the same time I would run both of them? When I say supplement heat I mean that it will be run mostly in the evenings and on the weekends when we are home but will not be my primary heat source.