Basement returns

My basement is 1500 sq. ft. The furnace is down there. There are four registers into the basement, all directly on the plenum (correct word?). I cannot find any air returns as exist in the rest of the house. There are plenty of returns in the basement leading upstairs but none of these opens to the basement.
How does air into the basement get returned to the furnace?
Peter.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

In the last house I was in with a basement, there was a return on the main cold air return as it came down from the upstairs. Just a 6" hole with a plenum (?) in it.
--
Jim Sullivan
seattle, washington
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
In my home I have 2 bsmt returns, both "plumbed" inside the furnace room itself. One goes to an enclosed BedRm, the other to a larger open area. If I finish more rooms, I'd try to add returns to any "doored" areas. The furnace room is a 2x4 enclosed area. Two "channels" are paneled off and a return is taped into each of those and then into the return ducting. I just had this redone a week ago, but I'm still questioning why they used 6" round duct to each of those channels instead of just running a smaller plenum across to both channels and directly into the return. Maybe they just didn't think about it -or- maybe there is some reason for not doing it that way.
On Mon, 10 Jan 2005 18:32:26 -0500, "PVR"

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.