I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.

Be carefull it is not rated R6 if its the bubble wrap Im thinkng of,
read it carefully, I think its a radiant barrier.

sherwindu wrote:

I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.

How much you save (if any) will depend on how much heat loss you're
getting via the ducts to begin with. If they're already insulated,
I suspect you might not see enough improvement to pay for the
bubblewrap stuff (if it's what I'm thinking of, it's not cheap).

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

According to sherwindu :
I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.

It's very difficult to even try to estimate without having any knowledge
of your installation/climate.

That said, chances are that it will be noticable savings if you
compare equivalent periods.

In an externally vented/drafty crawlspace, you could be losing a _lot_ of
heat from the bare ducts.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Chris Lewis wrote:

According to sherwindu :

I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.


It's very difficult to even try to estimate without having any knowledge
of your installation/climate.

That said, chances are that it will be noticable savings if you
compare equivalent periods.

In an externally vented/drafty crawlspace, you could be losing a _lot_ of
heat from the bare ducts.

I don't see where he said they were bare ducts.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

Ducts should be sealed with mastic first, fiberglass is better than
bubble crap, higher R and much cheaper. Best way is slide on duct
insulation. Bubble wrap I would not waste my time with and dought if it
is R 6 more likely its R 1 or less per inch

According to sherwindu :
I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.

Take the square foot surface of the duct, divide by R6, multiply by the
ambient temperature, add the relative humidity and that is the percentage of
your gas bill you save.

Edwin Pawlowski errs again:

According to sherwindu :

I am in the process of wrapping the forced air heating ducts in my crawl
space with a material that looks like bubblewrap with foil on both sides.
Does anyone have any idea of how much savings this will be on my gas bill?
The insullation is rated at R6, but I cannot relate this to actual savings
in energy.

Take the square foot surface of the duct, divide by R6...

.... 70 ft^2 of R1 duct might lose (130-50)70ft^2/R1 = 5.6K Btu/h to a 50 F
crawl space.

multiply by the ambient temperature, add the relative humidity and that
is the percentage of your gas bill you save.

Wrapping the duct would save 70ft^2/R6x50F+50%RH = 633% of the gas bill? :-)

Wrapping the duct would reduce the heat loss to (130-50)70ft^2/R7 = 800 Btu/h.

Then again, with an airtight crawlspace above a vapor barrier, a lot of this
heat could end up in the house. Maybe it's better to insulate the crawlspace.

Nick

Everyone Assumes its R6, did anyone read packing lit with that stuff,
the ratings are not certified and state " Like R 6' its a BS rating
just like " Insulating ceramic paint". Its a radiant barrier, foilfaced
duct R 7 fiberglass is R 7 certified, plus radiant barrier. The price vs
effectivness of bubble wrap to fiberglass make bubble wrap a joke. after
all its just bubble wrap.

wrote in message
...
Edwin Pawlowski errs again:

According to sherwindu :

I am in the process of wrapping the forced air heating ducts in my
crawl
space with a material that looks like bubblewrap with foil on both
sides.
Does anyone have any idea of how much savings this will be on my gas
bill?
The insullation is rated at R6, but I cannot relate this to actual
savings
in energy.

Take the square foot surface of the duct, divide by R6...

... 70 ft^2 of R1 duct might lose (130-50)70ft^2/R1 = 5.6K Btu/h to a 50 F
crawl space.

multiply by the ambient temperature, add the relative humidity and that
is the percentage of your gas bill you save.

Wrapping the duct would save 70ft^2/R6x50F+50%RH = 633% of the gas bill?
:-)

Wrapping the duct would reduce the heat loss to (130-50)70ft^2/R7 = 800
Btu/h.

Then again, with an airtight crawlspace above a vapor barrier, a lot of
this
heat could end up in the house. Maybe it's better to insulate the
crawlspace.

Nick


HAve you seen a conditioned crawl yet?

Before insulating your ducts that run thru the crawl space you will want to
seal them first -- duct mastic is considered best though I've used the foil
tape to seal all the seams. I've used foil tape that has held up very well
over ten years now. Don't use regular duct tape -- it doesn't last. Seal
the seams of the heating ducts as well as the return air ducts.

I've used the fiberglass duct insulation by Manville that I picked up at
Lowes.

After sealing my ducts in my crawl space and then insulating all the heating
and air return ducts I noticed a big improvement in the air flow and the
heat of the air from the registers as far as how much there are a lot of
SWAG methods that others have talked about but I do know I'm saving now for
the life of the house and since I did the work myself my only costs were
materials and time.


"sherwindu" wrote in message
...
I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.

"sherwindu" wrote in message
...
I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.


Are you wrapping the bubble wrap directly on the ductwork or are you putting
an air space between the BW and the duct?

"sherwindu" wrote in message
...
I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.



http://www.wapa.gov/es/calc.htm

this site has some interesting calculators.
I have never used the heating one, but the a/c calculator has some
remarkable numbers when you play around with duct insulation.

If you have not bought the R-6 then I would definitely think about something
higher (according to the calculator).

Personally I would not use the stuff your installing. I would stick to
fiberglass. I wrapped my fathers ducts in the garage. I used R-19 bats. Cut
to length, lath to nail to the ceiling and tape the edges. He had a double
garage, and the duct work was 2/3 of the width. Lowered the a/c bill $40 the
first month. Heat was a little more. Sorry, it was a long time ago and I do
not remember all of the numbers.

"Jay Stootzmann" wrote in message
news:kYUrf.651344$x96.457762@attbi_s72...
Before insulating your ducts that run thru the crawl space you will want
to seal them first -- duct mastic is considered best though I've used the
foil tape to seal all the seams. I've used foil tape that has held up
very well over ten years now. Don't use regular duct tape -- it doesn't
last. Seal the seams of the heating ducts as well as the return air
ducts.

I've used the fiberglass duct insulation by Manville that I picked up at
Lowes.

After sealing my ducts in my crawl space and then insulating all the
heating and air return ducts I noticed a big improvement in the air flow
and the heat of the air from the registers as far as how much there are a
lot of SWAG methods that others have talked about but I do know I'm saving
now for the life of the house and since I did the work myself my only
costs were materials and time.


Good, altho the best way to do it is the following:

Seal all seals with at least two wraps of UL181-A-B metal tape with an
acrylic adhesive, then, coat with elastomeric mastic. Once dry, cover with
Owens Corning R7.6 duct wrap, maintaining the 2.5 inch rule, and then seal
the seam with the proper tape and sealer tool. As an added measure, one
should take and staple the tape to the wrap. The staple gun used for this
isnt cheap...a good swedish made gun like we use runs about $100 and of
course, uses a special staple for just this, turning the ends out of the
staple and adding extra protection against the tape falling off.


"sherwindu" wrote in message
...
I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.

Sorry for not being more explicit in describing my situation. The ducts are
bare metal. I have
cut sections of the insulation and wrapped them around the cylindrical duct
pipes, sealing each
section with aluminum tape. The insulation is called Reflectix. They claim to
block up to 97%
of radiant heat. They indicate different R values for various applications, but
R-6 for bare ducts.
I know from checking that when there is hot air flowing through the ducts, the
bare uncovered
portions are very warm to the touch, while the covered sections are barely warm
to the touch.
There is no air gap between the insulation and the pipes, but the inner 'bubble
wrap' should
provide some sort of trapped air barrier. I have done about 30% of the job and
trying to
decide to finish it, or not. We had very cold temperatures last few weeks in
the Chicago area,
but now the temperatures are moderating. My gas bill for December was almost
double of what
it was last year for the same number of consumed therms. This insulation sells
for about $16 for
a 16" by 25' roll, and so far I have used 2 rolls. I have not blocked the vents
in my crawl because
I want some air circulation in their to prevent mold, etc. The ceiling of the
crawl is uninsulated, so
some of the heat makes it's way through the floor to the first floor living
space.

HeatMan wrote:

"sherwindu" wrote in message
...
I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.


Are you wrapping the bubble wrap directly on the ductwork or are you putting
an air space between the BW and the duct?

Then you didn't do it correctly.

The Reflectix is supposed to have an air gap between the insulation and the
duct. THAT'S what get's the wrap an R6.

The inner bubble wrap don't do anything.

"sherwindu" wrote in message
...
Sorry for not being more explicit in describing my situation. The ducts
are
bare metal. I have
cut sections of the insulation and wrapped them around the cylindrical
duct
pipes, sealing each
section with aluminum tape. The insulation is called Reflectix. They
claim to
block up to 97%
of radiant heat. They indicate different R values for various
applications, but
R-6 for bare ducts.
I know from checking that when there is hot air flowing through the ducts,
the
bare uncovered
portions are very warm to the touch, while the covered sections are barely
warm
to the touch.
There is no air gap between the insulation and the pipes, but the inner
'bubble
wrap' should
provide some sort of trapped air barrier. I have done about 30% of the
job and
trying to
decide to finish it, or not. We had very cold temperatures last few weeks
in
the Chicago area,
but now the temperatures are moderating. My gas bill for December was
almost
double of what
it was last year for the same number of consumed therms. This insulation
sells
for about $16 for
a 16" by 25' roll, and so far I have used 2 rolls. I have not blocked the
vents
in my crawl because
I want some air circulation in their to prevent mold, etc. The ceiling of
the
crawl is uninsulated, so
some of the heat makes it's way through the floor to the first floor
living
space.

HeatMan wrote:

"sherwindu" wrote in message
...
I am in the process of wrapping the forced air heating ducts in my
crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.


Are you wrapping the bubble wrap directly on the ductwork or are you
putting
an air space between the BW and the duct?

With Reflectix, you only get the full R-value if you place spacers
under the wrap - read the directions carefully. The spacers are to
provide a layer of trapped air between the wrap and the ducts. You are
probably achiving significantly less than R-6.5 if you didn't do this,
but another option is to wrap the ducts twice around with the wrap.
In the real world, I can tell you that in a similar situation, crawl
with vents, uninsulated floor, my coldest room increased in temperature
approx 2-3 degrees, which is significant but not mind blowing. In our
case, it solved a sticky problem of two rooms which had had a ceiling
vaulted without a proper increase in the heating mechanics.
I do however question the wrapping of the return ducts. In that case,
the temperature differential between the duct air and the surround air
is quite a bit less than the supply duct air and the crawl air, and
therefore the heat loss is less, and less can be accomplished by
wraping. Cetainly the payback is much longer.
I would also partially block the air vents in the winter. Conditions
are so dry then from heating (in the crawl) that there should not be a
problem, and you will reduce the effect of cold air blowing up under
your floors. Only in the attic would I NOT block the vents, as your
moist heated air rises to that level.


sherwindu wrote:
Sorry for not being more explicit in describing my situation. The ducts are
bare metal. I have
cut sections of the insulation and wrapped them around the cylindrical duct
pipes, sealing each
section with aluminum tape. The insulation is called Reflectix. They claim to
block up to 97%
of radiant heat. They indicate different R values for various applications, but
R-6 for bare ducts.
I know from checking that when there is hot air flowing through the ducts, the
bare uncovered
portions are very warm to the touch, while the covered sections are barely warm
to the touch.
There is no air gap between the insulation and the pipes, but the inner 'bubble
wrap' should
provide some sort of trapped air barrier. I have done about 30% of the job and
trying to
decide to finish it, or not. We had very cold temperatures last few weeks in
the Chicago area,
but now the temperatures are moderating. My gas bill for December was almost
double of what
it was last year for the same number of consumed therms. This insulation sells
for about $16 for
a 16" by 25' roll, and so far I have used 2 rolls. I have not blocked the vents
in my crawl because
I want some air circulation in their to prevent mold, etc. The ceiling of the
crawl is uninsulated, so
some of the heat makes it's way through the floor to the first floor living
space.

HeatMan wrote:

"sherwindu" wrote in message
...
I am in the process of wrapping the forced air heating ducts in my crawl
space with
a material that looks like bubblewrap with foil on both sides. Does
anyone have any
idea of how much savings this will be on my gas bill? The insullation
is rated at R6, but I cannot relate this to actual savings in energy.


Are you wrapping the bubble wrap directly on the ductwork or are you putting
an air space between the BW and the duct?

Reflextic, yes Ive seen that crap, as you read it says " like R6" just
like insulating paint says its "like R" whatever. The key work is "Like"
it is not a certified rating, don`t you even wonder why Reflextic has
different " like" ratings for different applications. Get a Cerfified
insulation, one that is industry accepted and known, Fiberglass. And
best is something designed for your job.

We have used the Reflectix in several aplications and it seems to do
what is claimed. Best bet is to put a spiral of 2" wide Reflectix down
the pipe, to provide additional air space. Then cover that with a full
layer of reflectix and overlap the seams 2". Then tape the seams with
foil tape.

R-6 fiberglass duct wrap also works well, as long as it is is not
compressed. R-6 ductwrap is approx. 2.5" thick. If it is applied
tight to the duct, so that it "Looks Nice", it compresses the
insulation and can reduce the R-factor to as little as R-2. Measure
the circumference of the duct and add 14.5". Cut that much duct wrap
and wrap it around the duct with a 2" overlap. Staple and tape the
seams. Use only tape rated UL-181 B-FX. The 14.5" add-on stretch out
is the amount recommended by NAIMA (North American Insulation
Manufacturers Association.) for 2.5" thick duct wrap installed on round
duct.. Different thicknesses have different recommended stretchouts.
For 2.5" thick wrap on rectangular duct the recommended add on is
12.5".

Stretch

On cost alone fiberglass wins.

HeatMan wrote:
Then you didn't do it correctly.

The Reflectix is supposed to have an air gap between the insulation and the
duct. THAT'S what get's the wrap an R6.

The inner bubble wrap don't do anything.

snip

Are you sure? I thought the necessary air gap consisted of the air in
the bubbles. Otherwise what's the point of the bubbles?

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

"CJT" wrote in message
...
HeatMan wrote:
Then you didn't do it correctly.

The Reflectix is supposed to have an air gap between the insulation and
the
duct. THAT'S what get's the wrap an R6.

The inner bubble wrap don't do anything.

snip

Are you sure? I thought the necessary air gap consisted of the air in
the bubbles. Otherwise what's the point of the bubbles?


Yes, I'm sure. The bubbles hold the air inside the air space.

Install one piece correctly and the other in the haphazard way you
mentioned. Get a surface reading thermometer from Radio Shack(no, I don't
have a link) and 'shoot' the insulation. I'll bet you see a warmer surface
on the haphazard Reflectix.

I have checked further with the web site of Reflectix, which I should have done
in the
first place. They claim their insulation gives about a 4.2 R value if applied
with no air
gap, as opposed to the R-6 value with a single air gap. This value goes up to
an even
higher value of about R-15 if a second layer with another air gap is applied.

I somewhat fault the company for showing nice pictures of the various ways this
stuff
can be used, but nothing about how to install it over ducting to get the best
results.
There are some instructions for crawl spaces, but nothing specific to ducts.
All they had to do was point people to their web site where everything is
explained quite clearly. Anyone can check the site yourselves at
www.reflectixinc.com. That's
another problem with buying at Builder stores. The prices are cheaper, but you
seldom
find anyone knowledgable about what they are selling. Hardware stores do much
better, in this respect.

HeatMan wrote:

"CJT" wrote in message
...
HeatMan wrote:
Then you didn't do it correctly.

The Reflectix is supposed to have an air gap between the insulation and
the
duct. THAT'S what get's the wrap an R6.

The inner bubble wrap don't do anything.

snip

Are you sure? I thought the necessary air gap consisted of the air in
the bubbles. Otherwise what's the point of the bubbles?


Yes, I'm sure. The bubbles hold the air inside the air space.

Install one piece correctly and the other in the haphazard way you
mentioned. Get a surface reading thermometer from Radio Shack(no, I don't
have a link) and 'shoot' the insulation. I'll bet you see a warmer surface
on the haphazard Reflectix.