Ductboard vs. metal ducts?
Etmyshrts
Yes ductboard does in fact SUCK!!! Breathing in fiberglass each time
the system runs are one of the many downsides of ductboard. (funny
I can't think of any upsides of ductboard)
Everyone says how cheap ductboard is. It depends on how often you
plan on replacing your ductwork.
Even when it is installed properly, which is rare, ductboard will need
to be re-secured, sealed, etc...
A better choice would be to use the cardboard that the equipment is shipped
in.
Uraprat wrote in message <19971121022...@ladder01.news.aol.com>...
>Hi All,
>
> I am in the process of planning and purchasing a heating and A/C
system
>and have been stumped on a final decision, which I must make. My favorite
HVAC
>contractor (of 3), says that they prefer to sell, use, and install ducts
made
>from ductboard instead of fabricated metal. I believe it is much cheaper
and
>easier to fabricate and install ductboard, which would explain their
>preference. They said that they will do metal ducts in locations, where it
>makes sense or where it is required, but for an average home ductboard is
fine.
> I have always heard that ductboard is a really poor choice, compared to
metal
>duct. Does ductboard suck as much as I think it does?
> If it helps, the system is going to be installed in the basement of a
>house which is a one story with a full basement, which I am finishing off
and
>is going to be heated and cooled, the ductwork will not be boxed in, it
will be
>exposed in the finished rooms. Total square footage of the house (up and
down
>stairs) is about 3250 square feet. Outside temperatures in summers range
in
>the mid 80's to 90's and winter extreme lows might be -05 to -10 degrees F.
> Any help, suggestions, or opinions will be greatly appreciated!
Thanks
>for your time.
>
> Best Wishes,
>Ura...@aol.com
Beverly & Jeremy Lowe
While I agree with the fact that unlined metal makes a better air delivery system
due to the lack of friction, there appears to be a great deal of misinformation
concerning fiberglass duct board here. Several major health related agencies not
associated with the HVAC industry have tested and confirmed that fiberglass duct
board poses no health related issues in the majority of uses. The respirable
particles that may enter the air stream are not a heath issue because of their size
and structure. This is quite unlike the particles generated by many types of attic
insulation and asbestos that have finer particle size and do to their light weight
stay air born for much longer time making them a greater health hazard.
Duct board is a cost effective alternative in certain low cost application and if
properly installed and left alone will give many years of service. The greatest
problem I have seen in the 2000+ homes we have blower door tested for leaks is not
the structural integrity of the duct board but rather the joint closure failing.
For this reason I strongly recommend the use of mastic to seal over any tape used
in the system.
Don't be afraid of duct board just be educated!
Uraprat wrote:
> Hi All,
>
> I am in the process of planning and purchasing a heating and A/C system
> and have been stumped on a final decision, which I must make. My favorite HVAC
> contractor (of 3), says that they prefer to sell, use, and install ducts made
> from ductboard instead of fabricated metal. I believe it is much cheaper and
> easier to fabricate and install ductboard, which would explain their
> preference. They said that they will do metal ducts in locations, where it
> makes sense or where it is required, but for an average home ductboard is fine.
> I have always heard that ductboard is a really poor choice, compared to metal
> duct. Does ductboard suck as much as I think it does?
> If it helps, the system is going to be installed in the basement of a
> house which is a one story with a full basement, which I am finishing off and
> is going to be heated and cooled, the ductwork will not be boxed in, it will be
> exposed in the finished rooms. Total square footage of the house (up and down
> stairs) is about 3250 square feet. Outside temperatures in summers range in
> the mid 80's to 90's and winter extreme lows might be -05 to -10 degrees F.
> Any help, suggestions, or opinions will be greatly appreciated! Thanks
> for your time.
>
> Best Wishes,
> Ura...@aol.com
--
Jeremy or Beverly Lowe
Woo...@gte.net
"Every one has a photographic mind........
some people just don't have film in the camera!"
Augustine
Thank you for your fine myth busting post. I am glad to see some else
you knows (and can verify) what I was told when I was told. There is no
increased health hazard from use of duct board vs sheet metal.
Mark Elder
That's not entirely correct either. There are currently only concerns
about the potential effects of airborne fiberglass. To the best
of my knowledge, nothing has been clinically demonstrated.
However, there are demonstrated health risks associated with mold and
dust mites. Fiberglass duct board has been shown to provide a medium
for development of both. IMO these are more serious IAQ issues. Even
if there were no installation damage and quality issues, this would be
enough to make me very wary of ductboard except in unique applications.
Regards,
Mark Elder
Stan Debick
Please take no offense, but I believe that CA lists H20 as a carcinogen -
they tend to over-react just a bit.
However, I also posted a question about the merits of ductboard vs. sheet
metal a few weeks ago, and after a great deal of research have concluded
that there are relatively few pluses when using ductboard. I located a
local sheet metal shop and HVAC tech who was more than happy to help me size
the ductwork that I needed for my furnace/house, and had the works
fabricated for ~$175 more than the cost of using ductboard. It has been
extremely easy to install, and I now know that I have a lifetime (barring
tornadoes! ;-)) installation. I just can't see where the cost savings would
merit using ductboard. It all comes back to "You get what you pay for."
HyJude22 wrote in message <19971129032...@ladder01.news.aol.com>...
>>The respirable
>>particles that may enter the air stream are not a heath issue because of
>>their size
>>and structure.
>
>Who would promote the breathing of glass when there is no reason not to use
>metal, there is no way to seal ductboard where you cut it to fold it and
the
>end of joints. Look in Trane units they have a sticker saying that in
>Calif.fiberglass is a cancer agent.
HyJude22
John
Augustine <augu...@telenet.net> wrote:
You will live in filth in that house as long as you own it. There is
NO WAY to clean ductboard or prevent SIGNIFICANT colonies of mold,
fungus, and mites from living in it.
John
Beverly & Jeremy Lowe
You have a valid point Mark. However the issue that sadly still exists is in
various areas of the country is that sheet metal is reserved for large
commercial applications. Even our local school boards have accepted duct board
as a cost saving alternative to sheet metal. I live in the Tampa/St. Pete area
in florida and would love to find a sheet metal shop that could make the
product cost competitive in the local area. New construction has made duct
board and flex duct the product of choice.
Mark Elder wrote:
> Augustine wrote:
> >
> > Beverly & Jeremy Lowe wrote:
> >
> > > While I agree with the fact that unlined metal makes a better air
> > > delivery system
> > > due to the lack of friction, there appears to be a great deal of
> > > misinformation
> > > concerning fiberglass duct board here. Several major health related
> > > agencies not
> > > associated with the HVAC industry have tested and confirmed that
> > > fiberglass duct
> > > board poses no health related issues in the majority of uses. The
> > > respirable
> > > particles that may enter the air stream are not a heath issue because
> > > of their size
> > > and structure. This is quite unlike the particles generated by many
> > > types of attic
> > > insulation and asbestos that have finer particle size and do to their
> > > light weight
> > > stay air born for much longer time making them a greater health
> > > hazard.
> > >
> > > Duct board is a cost effective alternative in certain low cost
> > > application and if
> > > properly installed and left alone will give many years of service. The
> > > greatest
> > > problem I have seen in the 2000+ homes we have blower door tested for
> > > leaks is not
> > > the structural integrity of the duct board but rather the joint
> > > closure failing.
> > > For this reason I strongly recommend the use of mastic to seal over
> > > any tape used
> > > in the system.
> > >
> > > Don't be afraid of duct board just be educated!
> > >
> >
> > Thank you for your fine myth busting post. I am glad to see some else
> > you knows (and can verify) what I was told when I was told. There is no
> > increased health hazard from use of duct board vs sheet metal.
>
> That's not entirely correct either. There are currently only concerns
> about the potential effects of airborne fiberglass. To the best
> of my knowledge, nothing has been clinically demonstrated.
>
> However, there are demonstrated health risks associated with mold and
> dust mites. Fiberglass duct board has been shown to provide a medium
> for development of both. IMO these are more serious IAQ issues. Even
> if there were no installation damage and quality issues, this would be
> enough to make me very wary of ductboard except in unique applications.
>
> Regards,
> Mark Elder
--
Beverly & Jeremy Lowe
John, I am sorry but I disagree with your post. Mold grows ONLY in a climate
with the following three factors. (1) Moisture. A RH of 55% or higher must
be maintained for 24-48 hours to allow mold growth. (2) Food. Any type of
biological growth must have a food source. Mold does not eat fiberglass, it
simply colonizes on the porous stratified surface. It still requires some
type of food. (3) Temperature. Molds can grow from the 40's to well over
120*
This simply means that to prevent mold growth you eliminate or control one
of the three items. While it is almost impossible to completely eliminate
the food source of most molds a enhanced air filtration system, and good
humidity control can all but eliminate mold growth in most duct systems.
Hospitals have made a science of this to ensure clean areas for surgery and
treatment of ill patients.
I should point out that their are exceptions to every rule and especially in
the world of mold but I can assure you we frequently design and service
"Mold Free" air distribution systems (Less than 10 CFU per test)
John wrote:
> Augustine <augu...@telenet.net> wrote:
>
> You will live in filth in that house as long as you own it. There is
> NO WAY to clean ductboard or prevent SIGNIFICANT colonies of mold,
> fungus, and mites from living in it.
>
> John
>
> >Thank you for your fine myth busting post. I am glad to see some else
> >you knows (and can verify) what I was told when I was told. There is no
> >increased health hazard from use of duct board vs sheet metal.
> >
--
Jeremy or Beverly Lowe
HVAC and IAQ Consultant
Frank Vigil
While it may be true that certain responses here may be borderline
"hysteria" prone, it can be said with some certainty that ductboard
systems--overall--have a poor reputation in terms of durability as
well as the increased potential for supporting mold growth. Nearly
every paper I've read, including the EPA's studies, suggests that
ductboard systems provide an ideal environment for mold growth.
Certainly, if one were to be looking to install a *low cost* system,
spending the fewest dollars possible, ductboard may be considered.
This, so long as life-cycle costing were taken into account. The
ductboard had better be assembled and installed precisely per
manufacturer's specifications (a feat I've seldom seen accomplished).
As others here have suggested, I too have witnessed a significant
percentage of failure with duct board systems.
Frank