House is in Michigan, about 20 years old, 2 story 2200 sqaure feet with walkout basement. When I moved in 10 years ago it was recommeded that I put in a 6" fresh air intake on the cold air return and a 6" combustion supply that just hung open ended in the furnace room. I Had both put in, but last year I had my water heater and furnace replaced, both are direct power vents. They capped the combustion air duct, but left the fresh air intake. A new service guy came out on the annual maintenance visit and noticed the fresh air intake. He said that it wasn't necessary and that I was wasting $$ of energy having it open. It has a manual damper that typically is half open.
What's the concensious these days on the fresh air intake?