The hvac supply ducts in my attic are insulated and have a black cover.
The ducts in the basement have a silver cover. Is this normal? Or
does it matter? I would have thought that the black covered insulation
in the attic would absorb attic heat and increase the temperature of
the air supply.

-Jim

Is it Flex duct?


"Jim" wrote in message
oups.com...
The hvac supply ducts in my attic are insulated and have a black cover.
The ducts in the basement have a silver cover. Is this normal? Or
does it matter? I would have thought that the black covered insulation
in the attic would absorb attic heat and increase the temperature of
the air supply.

-Jim

Yes.

"Jim" wrote in message
ups.com...
Yes.


Some flex has got a plastic vapor barrier and some has a metalized
barrier....

"Jim" wrote in message

The hvac supply ducts in my attic are insulated and have a black
cover.
The ducts in the basement have a silver cover. Is this normal? Or
does it matter? I would have thought that the black covered
insulation
in the attic would absorb attic heat and increase the temperature of
the air supply.

Timely question. I wanted to insulate the ducts in my garage. Have
seen the black, but wondered it it's just garbage bags or sheet
plastic stapled over normal attic fiberglass R11 or similar.

Anyone have a suggestion on what to use? Mine are normal galvanized
ducts, some rectangular and some round.

Local Home Depot looks at me funny, when I ask about it.

Rich

Would one be preferred in an attic over the other?

Thanks for replying.

-Jim

Jim wrote:

Would one be preferred in an attic over the other?

Thanks for replying.

Flex duct is not to be preferred period. But to answer your question:
It's the R value that matters, not the color.

hvacrmedic

RP,
Flex duct is easier to seal and usually performs better thermally.
Sheet metal will pass more air with the same static pressure. Flex
duct is quieter.

It is a trade off, depending on your situation.

With sheet metal, to have a tight system, you must seal every gore on
every elbow. You must seal every joint in the duct, plus you must seal
every longitudinal seam. Then you hust do the same thing with the
wrap. And if you install the wrap tight so it looks nice, the actual
R-value is about 1/2 rated value.

With flex duct, you just have to seal the connections at the ends, but
it must be supported at closer intervals with wider straps. But you
get full rated R-value for the entite length.

Stretch

Stretch wrote:

RP,
Flex duct is easier to seal and usually performs better thermally.
Sheet metal will pass more air with the same static pressure. Flex
duct is quieter.

It is a trade off, depending on your situation.

With sheet metal, to have a tight system, you must seal every gore on
every elbow. You must seal every joint in the duct, plus you must seal
every longitudinal seam. Then you hust do the same thing with the
wrap. And if you install the wrap tight so it looks nice, the actual
R-value is about 1/2 rated value.

With flex duct, you just have to seal the connections at the ends, but
it must be supported at closer intervals with wider straps. But you
get full rated R-value for the entite length.

Which is why it isn't legal here except for drops.

hvacrmedic

"Jim" wrote in message
oups.com...
Would one be preferred in an attic over the other?

Thanks for replying.

-Jim


This is Turtle

if I was going to use Flex Duct. It would be the Black for it is made to be sun
resistant and not crack or fall a part like the silver will in sun light.

TURTLE

Thank you all.

-JIm

"Jim" wrote in message
oups.com...
Would one be preferred in an attic over the other?

Thanks for replying.

-Jim


Stretch and RP answered before I could and their answers were the same mine
would have been.

I don't really care for flex because of the way it's usually run. It also
has a higher resistance than the same size hard pipe.