Its tottering between 80-84 thermostat kicks in at 80 takes it to 84 the offs itI figured the end of the uth was getting cold and slowing the current so I popped a bit of card over to insulate the end that is in open air and card under to stop the cold surface from doing the same to the underside, I'm going to replace the card with either cork or ruber to be on the safe side but it seems to be doing the trick.. Do you think it would be a good idea to cover up a few of the vents to try and trap a little heat or will purely ground heat do the job