I had someone come take a look at the attic yesterday to do an assessment. He uses the sprayable foam insulation and said that he would spray the ceiling of the attic rather than the floor (and remove the old insulation) and close up the two attic fan vent areas. He called it a "ventless attic" and I've never heard of this before. He claims it's safer and better for air circulation. Has anyone ever heard of this? Also, does it make sense to remove the old insulation or could it be kept there? I worry about all the dust and debris it would leave behind upon removal.
What he's suggesting would be to make the attic inside the building envelope, therefore you'd be heating and cooling the attic along with the house.
You either need insulation at the attic floor or attic ceiling. One or the other is the building envelope. If you google some of the terms you can learn a lot.
If the house is a standard, single open roof I'd vote for keeping the insulation on the floor.
Maybe get a few more opinions?