Basement Air Intake

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!

I do not like vented Crawl spaces …

That is a lot of information Roy, thanks, but does that apply to a full size basement as well?

Combustion air for boiler.

Roy, the info you provided has absolutely nothing to do with his post??


Thanks for your opinion . I disagree with you.

Yes full basement should not be open to the outside .

That could be a louvered control exterior combustion air intake fan.

Power Vent Openings & Louvers for Combustion Air

Thanks good information Marcel

Thanks Marcel, I will see these with manual dampers, which makes no sense at all.

I noticed today that there is a massive]( air return in my unfinished basement. The opening is about 2 meters from the blower, and as large in diameter as the return duct coming from the upstairs
Will capping off this return or limiting the basement’s supply vent cause any problems for the equipment, or lower efficiency?