I have an older Carrier 58RAV furnace (92k BTU) and I was under the house to inspect the ductwork since cold air was billowing into the house and it's all messed up. It looks like it was done a previous home owner. I'd like to replace it since it's all coming apart and I am heating the neighborhood up. I looked online though and can't find out how many CFM this furnace outputs. Does anyone know?