Anyone know what the purpose of this is? From inside the crawl space, I found this duct attached to a flex duct that goes up through the floor. The duct has a wire screen in it to keep out rodents.
Here’s my guess. The structure was a double-wide mobile home. It had a pre-fab metal fireplace with metal chimney. The duct was under the area of the fireplace. I think it is to provide combustion air to a tightly built structure. Do you agree?
If that’s what it is, when the HVAC is on, will it not suck in air from the crawl space???