Four inch PVC pipe coming into the basement of the house attached to a fan.
Fan is drawing in air from the outside only when the oil fired hot water baseboard system is run.
The vertical insulated portion stops about 18" from the floor and it is anchored to the floor.
Has anyone seen this before and the purpose of it.
Why on a freezing cold day would you run the boiler and draw cold air into the basement?
Thanks in advance!