"Goedjn" wrote in message
...
On 22 Dec 2006 07:34:34 -0800, "dpb" wrote:


Eigenvector wrote:
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
...

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.

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

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.


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


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.