Air Conditioning - A/C intake leak in attic
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coryengel
07-31-04, 06:25 PM
I was snooping around in the attic of my new house this morning trying to get some clues as to why it's so hard to keep the house cool. It looks like there are a variety of reasons (not the least of which is that I have two attic fans that were not switched on), but one relating to the A/C seems major and I want to find out what people here think.
The house has central A/C. There are two air intake vents in my house--one in a hallway ceiling and one in a wall above a staircase. In the attic, two big round insulated ducts come together from those vents and go down to the blower in the garage. However, the vent above the staircase has a 14" uninsulated galvanized metal box in the middle of it, and get this: the box has NO BOTTOM IN IT. It has a lip on the bottom where it looks like it was once nailed down, but now it's just hanging there.
What's worse, when the fan blows, it sucks not only hot attic air (instead of air from inside vents), but also whatever other stuff is in the attic: dust, bugs, bits of insulation (I turned the blower on and then went up and looked at it). I can't wait to look at the filter and see what all's on there.
So here's my question: I can cut a 14" square piece of wood and nail the box to it easily enough, and I can also caulk the seam to make it airtight. However, is that really sufficient, considering that it isn't insulated? Is there a better way to do it, perhaps by fitting a new piece of insulated duct between the other two instead of having this box in the middle?
Also out of curiosity, what is/was this box for? This part of the house has been remodeled and the A/C is only 8 years old, so I suspect it may be a relic from a previous configuration of the heat/cooling system.
The house has central A/C. There are two air intake vents in my house--one in a hallway ceiling and one in a wall above a staircase. In the attic, two big round insulated ducts come together from those vents and go down to the blower in the garage. However, the vent above the staircase has a 14" uninsulated galvanized metal box in the middle of it, and get this: the box has NO BOTTOM IN IT. It has a lip on the bottom where it looks like it was once nailed down, but now it's just hanging there.
What's worse, when the fan blows, it sucks not only hot attic air (instead of air from inside vents), but also whatever other stuff is in the attic: dust, bugs, bits of insulation (I turned the blower on and then went up and looked at it). I can't wait to look at the filter and see what all's on there.
So here's my question: I can cut a 14" square piece of wood and nail the box to it easily enough, and I can also caulk the seam to make it airtight. However, is that really sufficient, considering that it isn't insulated? Is there a better way to do it, perhaps by fitting a new piece of insulated duct between the other two instead of having this box in the middle?
Also out of curiosity, what is/was this box for? This part of the house has been remodeled and the A/C is only 8 years old, so I suspect it may be a relic from a previous configuration of the heat/cooling system.
Ed Imeduc
07-31-04, 07:06 PM
:eek: :eek: Sounds like that is where the old cold air return was. How far do you want to go here You could make up a new box just like it out of fiberglass duct board and put it in. Or like you say cut a square board about 20"X20" for it to set on put a duct board plug in the bottom
on the board. put duct board over the whole box and seal it up with the aluminum tape then go over it with the mastic duct sealant . Also check the AC coil in there to see if its clean for sure.
ED ;)
on the board. put duct board over the whole box and seal it up with the aluminum tape then go over it with the mastic duct sealant . Also check the AC coil in there to see if its clean for sure.
ED ;)
coryengel
07-31-04, 07:38 PM
What's a duct board plug?