venting to nowhere

[Eigenvector]

I have a couple of ideas as to what these are there for, but I have vents in my ceilings that go to nowhere. They are in all the rooms, all of them go into the attic and are all connected to each other by regular ducting. But they don't exhaust anywhere.

I'm not exactly sure why they exist.

I'm thinking of two possibilities

1) They are from an aborted attempt at installing AC 2) They are for the purpose of dumping hot air into the attic.

I'd always assumed that they all connected up with each other and routed back to the furnace, but the ducting literally goes nowhere - it's all contained in the attic and it's all SEALED - meaning there is no exit port.

What got me wondering about it was whether or not I should seal the vents during the winter to conserve heat.

[suzzannes05]

[suzzannes05]

[Mark]

I wished I'd done that when I put my addition on 20 years ago. We've had to do a lot of work since to retrofit the ductwork in for A/C.

(Suzzannes05 - why don't you turn your CAPLOCK off - using all caps is considered SHOUTING.)

[dpb]

...

I'd venture w/ Suzzanne they were installed either when the house was built or during a major remodel w/ the intent of adding central heat/air which hasn't been done. If they're uninsulated, they were undoubtedly the returns.

Wouldn't hurt a thing, might help a tiny amount, but if they're not open, doubt if would see any real difference. If they were open, that would be another story, as then you could set up an nice flow path driven by thermal and pressure differences, but w/o the exit, there's no flow.

[Goedjn]

Or you could set up a blower fan in a few of them and use them to circulate heat from a wood-stove.

[RicodJour]

Not an aborted attempt, but foresight. Far cheaper and cleaner to install the ducting before the walls are drywalled.

Nah.

Closing the louvers shuts off most of it,but if you want to seal them up completely, I've found that using flexible magnetic vinyl sheet, like that used for truck signs, is about the easiest way to go. A local sign shop would sell you some scraps cheap.

R

[Eigenvector]

I did finally figure out what they were there for. It took following the shutoff switch for the furnace to make it all click together. See the furnace is in the basement, across the house from the garage. The shutoff switch for the furnace is next to the furnace, but is routed from the switch that goes to a box in the GARAGE, then from there to the fusebox on the other side of the house. It is the most inefficient setup I've ever seen, probably 60 feet of 14/2 - like they must have spend a fortune in copper when they could have run it 5 feet to the fusebox above the furnace. But, it makes sense when you consider that the old oil furnace was in the garage, vented using those ducts in the attic. Those vents are the ducts for the old oil furnace. So when they installed the new gas furnace, they literally routed the switch from the oil furnace switch location to the location of the gas furnace then installed new ducting for the gas furnace. That's my best guess, but it seems logical given the location of the exhaust vent of the oil furnace, the switch for the oil furnace, and the location of where the ducting terminates.

But here's the kicker. Some of you hinted about it as well. I'm thinking that I can install a ducting fan in the attic and use it to move hot air out of the house in the summer. Basically installing a fan in the vent and use that fan to draw hot air into the ducts and out the attic/roof vent. I think that would be an incredibly good way to remove hot air from the room during the hot summer nights.

[hallerb]

you CERTAIN one doesnt gpo down somewhere to feed the furnace?

What kinda of heat do you have? If its forced air theres a return somewhere/

They can use a wall cavaity for getting the air back to the basement

[Eigenvector]

Positive. The gas furnace return vents are in the floor of the hallway and the basement main room.

I know it sounds weird, but I mapped it today and they do not go anywhere.

[hallerb]

try causing some smoke around the vents with the furnace on and see if air moves

[trader4]

And if they do go nowhere, I'd still make sure they were blocked off in the winter. Leaving them open will still lose a good deal of heat, especially if they are uninsulated, which I suspect they are.