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Thread: duct cleaning
06-20-2009, 02:04 PM #1New Guest
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- Jun 2009
I have a opportunity to start a duct cleaning buisness. I would be cleaning ducts on homes that have had fire, smoke or water damage and after construction remodels. Also for home owners that just want their ducts cleaned. I have serched this site about equipment to purchase and pretty much ruled out any kind of rotobrush system. I want professional equipment to do the best job I can. I believe that word of mouth of a good job is the best way for a long term buisness. What I'm trying to find out is what are the opinions of the best equipment to get for the type of work I'll be doing and who provides the best training. I don't want to say that money is no object to get what I need but I do want to get the best I can without overkill. I don't want to be a fly by night buisness just to make the money. I want to do Professional duct cleaning and give the customer what they pay for.
Thanks for any input, Bill
06-20-2009, 11:30 PM #2Professional Member
- Join Date
- Jan 2008
- Clermont, Florida
I am sure that you prob already checked this out. It kind of gives some guidelines for consumers. It also says that some kind of vacuum system is the best. I know my company uses a ToraVac system. I think that that is a name brand not really sure. I have looked the net for them and found different kinds depending on how big you want to go.
I personall think that is a good money maker. People are concerned about health these days and even though that website says that there is no proof about health affects,we have had people write letters to our company saying that there allergies and asthema symptoms have been reduced greatly. Well anyways good luck.
06-20-2009, 11:55 PM #3Regular Guest
- Join Date
- Mar 2005
07-21-2009, 03:09 PM #4
If the ducts in your area are primarily unlined sheet metal, it can be worth while. If the ducts are primarily ductboard or flex or lined metal, then duct cleaning can do more harm than good. Look into that first.Remember, Air Conditioning begins with AIR.
07-21-2009, 07:16 PM #5Regular Guest
- Join Date
- Mar 2005
07-22-2009, 09:51 AM #6
A couple of things to look at:
Also see attached .pdf:
More studies have been done, none conclude duct cleaning is really good except those put out by people making duct cleaning equipment.
Another question: Do you have any background in HVAC? Do you understand ducts and heating & cooling equipment? If you don't have an HVAC background, I would not recommend duct cleaning as the place to start, especially if you don't serve some sort of apprenticeship.
Last edited by Kevin O'Neill; 07-22-2009 at 09:56 AM. Reason: additionRemember, Air Conditioning begins with AIR.
08-13-2009, 07:18 PM #7Professional Member
- Join Date
- Jun 2009
I agree with the post above, be careful, businesses have A LOT of luck attached to them. People who do some research will find out the EPA recommends AGAINST duct cleaning (not sure if this is for residential as well, but just took a IAQ course, and their information was for commercial usage)
08-24-2009, 09:20 PM #8Professional Member*
- Join Date
- Sep 2001
- McDonald PA
Actually what the EPA said was:
Knowledge about the potential benefits and possible problems of air duct cleaning is limited. Since conditions in every home are different, it is impossible to generalize about whether or not air duct cleaning in your home would be beneficial.
If no one in your household suffers from allergies or unexplained symptoms or illnesses and if, after a visual inspection of the inside of the ducts, you see no indication that your air ducts are contaminated with large deposits of dust or mold (no musty odor or visible mold growth), having your air ducts cleaned is probably unnecessary. It is normal for the return registers to get dusty as dust-laden air is pulled through the grate. This does not indicate that your air ducts are contaminated with heavy deposits of dust or debris; the registers can be easily vacuumed or removed and cleaned.
On the other hand, if family members are experiencing unusual or unexplained symptoms or illnesses that you think might be related to your home environment, you should discuss the situation with your doctor. EPA has published Indoor Air Quality: An Introduction for Health Professionals and The Inside Story: A Guide to Indoor Air Quality for guidance on identifying possible indoor air quality problems and ways to prevent or fix them.
You may consider having your air ducts cleaned simply because it seems logical that air ducts will get dirty over time and should occasionally be cleaned. While the debate about the value of periodic duct cleaning continues, no evidence suggests that such cleaning would be detrimental, provided that it is done properly.
On the other hand, if a service provider fails to follow proper duct cleaning procedures, duct cleaning can cause indoor air problems. For example, an inadequate vacuum collection system can release more dust, dirt, and other contaminants than if you had left the ducts alone. A careless or inadequately trained service provider can damage your ducts or heating and cooling system, possibly increasing your heating and air conditioning costs or forcing you to undertake difficult and costly repairs or replacements.
The truth is that there has never been a thorough unbiased study done of air duct cleaning. The positive studies were done by air duct cleaning companies and the negative ones by those with other agendas such as the company that was marketing an air cleaner.
That said you can't thoroughly clean anything with a glorified shop vac or some of the other junk that's on the market and even the best equipment takes time to do it right!The greatest pleasure in life is doing well at what others say can't be done at all!
08-25-2009, 07:49 AM #9Regular Guest
- Join Date
- Dec 2008
We have a lot of customers choosing textile ducting for this reason, Because the duct is taken away to be cleaned, there is no risk of the dust and bactiria being disturbed then re-introduced to the space one the air is tuned on again.
08-25-2009, 07:00 PM #10Professional Member*
- Join Date
- May 2004
- south louisiana
pretty interesting site..long way from these parts..but thanks for the link!The cure of the part should not be attempted without the cure of the whole. ~Plato
09-11-2009, 12:50 PM #11Professional Member*
- Join Date
- May 2008
As HVAC professionals, we have debated whether or not to "get" into duct cleaning at all. Right now, we don't do it. I feel uneasy about putting someone into a customer's home who is a "cleaning" professioinal, and then dealing with the possible complaints from Ms "my home is never clean enough!" type homeowner. As earlier posted, the proper methods must be used along with superior (top of line) equipment and then I fear having to deal with the "impossible" people. I'm sure there will be some, based on weird complaints we sometimes have while attempting to satisfy their HVAC needs, compound this with a "cleaning" type job, and I quake at attempting this service offering!!! I'm sure there are companies who are successful, but it would be interesting to see a study of the number of complaints from this field?? We simply offer and recommend quality air filter systems, it seems to work fine!
09-11-2009, 02:41 PM #12Professional Member*
- Join Date
- May 2004
- south louisiana
This is a portion of a 200+ page duct study done in 2009 by La. Dept of Natural Resourecs.
This was a study to determine the best method of sealing hard pipe ducts.
Exterior mastics, mastic applied to interior of ducts and areoseal type products.
The Polar Seal material consists of two components, namely an adhesive primer (Prime Security)
for filling gaps and a top coat (Top Security). Both materials are latex based allowing for water
cleanup. The manufacturer recommended two applications of the primer and one application of
the top coat. The purpose of the primer is to adhere to any surface and seal. The primer is still
adhesive once dried whereas the top coat is not. Therefore once the top coat is applied nonadhesive
seal is created. Also the top coat only properly adheres to the primer, and once dried it
is resistant to water.
Gaps were cut into the quarter inch test specimens. The gap sizes were 1/8”, 5/16”, and ¼” in
width, and six inches long. The gapped specimens were placed in the spray stand as floor,
sidewall and ceiling (or inverted) panels. The gun was aimed at a slight angle to allow build up
between the gaps from a distance of 12 inches. Using of 0.031” orifice spray tip and operating
pressure of approximately 1600 psi, the gaps were sprayed (with primer) in passes until the gaps
were approximately filled or the material began to drip.
Results for various surface orientations
The testing was repeated multiple times. During the tests it was noticed that in many cases that
material “run” down along the gap, which is not a desirable performance. This behavior was
mitigated when the material was sprayed at a lower rate, allowing a gradual “build up” inside the
gap. It also appears that set and dry times are significantly affected by humidity. The humidity
during testing (an uncontrolled environment) was 62%, and the material was observed to often
“run” prior to the commencement of setting, resulting in uneven coating thickness. Also, the
material did not completely dried when left overnight. Adjustment and optimization of the
spraying operation appears to be keys to reduce run-off and minimize drying time, two
characteristics essential for maximizing the commercial potential of this technology.
The test set up replicated a difficult spray scenario expected to be encountered in practice–an 8”
with an adjustable 90° elbow set to a full 90° bend. Several different tips were evaluated for the
distribution of the coating on the inside of the duct. It was found that all three tips (543, 532 and
517) deposited the material too quickly to be effective. Although the lower output tip #517 had
the lowest flow rate. To compensate we changed the angle nozzle to 45° with the adjustable
angle fitting on extension wand and performed further testing with the 517 tip. This
configuration resulted in an improved performance–although the coating thickness was still
somewhat excessive. We were able to successfully fill the 1/8” gap at the connection of the
straight duct section to the 90° fitting, however the material was observed to run out of the gap at
the crown of the metal duct under the action of gravity as it required a significant amount of time
One troubling observation was the long cure time of the thick coating. The literature stated that
the coating would dry sufficiently for a second coat in 20 minutes but it became apparent that
that time was for thin coats and a thick coating did not cure overnight. This is a significant
impediment to cost effective commercial sealing operations.
A thickening agent, an ultra-fine powder named Metakaolin, was selected to thicken the primer
to achieve the goal of changing the rheology of the coating to allow the material to “hang” or
stay in the gap while curing. The Metakaolin successfully increased the viscosity of the primer
but the sheer or thixotropic properties were not significantly improved. Thus, no noticeable
improvement was realized with this modification.
Next, the top coat was successfully applied and preformed well filling the gaps. However, after
been left for an overnight it was observed that the top coat had flowed out of the gaps and pooled
in the bottom of the duct. It became evident that the rheology of these coatings is a significant
issue. Also of concern is the cure time of the thickly applied top coat–although it dried somewhat
faster than the primer, it still flowed out of the sections before curing. The second layer of top
coat was applied to the duct section using the sprayer to the duct section. A pressure tested
conducted using a dust blaster-a differential pressure measuring device which quantifies the
amount of duct leakage–revealed that the duct was successfully sealed.
The capability to spray the material and fill a gap has been demonstrated during this testing.
However, given the time required to cure this material it is unlikely that a cost effective
commercial system for internal sealing would be feasible due to the long wait times between
coats. A search was conducted for alternative sealant materials with better thixotropic and
EVALUATING THE APPLICABILITY OF GEOPOLYMERS AS A DUCT SEALING MATERIAL
Based on the preliminary performance of the sealing coatings system it was determined that the
proposed system, although successfully applied, was not a candidate for a cost effective and
efficient method of fulfilling the objective. The materials took too long to cure and could not be
applied in sufficient thickness, without running, to fill gaps larger than 1/8”. Research on
alternative materials, including single component and two component coating materials, was
performed and a highly desirable candidate for a sealing material identified. The material is
geopolymer which has beneficial properties for this particular application including: low cost,
environmentally benign, bacterial growth resistance, ease of application, great rheological
properties, non flammable and excellent longevity. The laboratory evaluation focused on three
a) Brush application–advantageous because it will better facilitate working bend sections.
b) Trowel application–while producing a smoother finish this approach could be problematic in
bends–multiple small trowel sections that make up a whole unit could be employed.
c) Spin spray–using a centrifugal spinning head applicator.
ACCELERATE CURING OF POLAR SEAL MATERIAL
To overcome its prolong curing time it was attempted to accelerated curing of the Polar Seal
material by placing samples in the oven (at 140 F). A thin coat of the Primer was found to cure in
5 minutes, however a coat of Top Coat took 20 minutes to cure, during which the coating ran out
of the gaps that were filled. It was concluded that it might be possible to apply a primer prior to
the geopolymer with a quick cure. However, even with heat-based acceleration, the curing time
of the Polar Seal top coat was found to be too long.
The conclusions on the feasibility study of sealing duct leaks are as follows:
a) The return plenums, made of wood, can be cost-effectively sealed using this sealing
technology, in addition to sealing the larger holes by conventional methodologies.
The metal ducts can be sealed externally and hence can be used to seal the ducts at joints,
seams, turns and register boots after the ductwork has been laid and prior to insulating the
The metal ducts can also be sealed internally at common points of leaks such as joints,
seams, turns and register boots.
d) The sealant is effective for sealing gaps less than 0.325” (3/8”), and for sealing holes less
than 0.5” (1/2”) diameter.
e) The sealant is safe to use, and, when dry, does not contain organic compounds, thus it
cannot support the growth of mold.
However full scale testing of spraying the compound in actual conditions showed
significant problems due to dripping of the compound and comparatively long drying
a) Mastic, a well known compound for externally sealing ducts, was considered. This
material could not be sprayed, but it did not have the problems associated with the
previously explored compound. A method of internally sealing cylindrical ducts
internally via applying mastic was devised. Essentially the recommendation for the final
solution is to utilize a brush-applied, duct-mastic.
my pov has always been that a well sealed duct system will not require duct cleaning.
quick seal materials while easily applied are not as effective as mastic sealing.
(wet mastic applied to exterior with brush) I can't imagine internally sealing ducts with mastic...guess these guys had lots of time to test using this method, but itrw...I don't see it happening.
Anyhow just wanted to share what I had read.
have a great weekend everyone!The cure of the part should not be attempted without the cure of the whole. ~Plato
09-28-2009, 11:43 PM #13Regular Guest
- Join Date
- Dec 2007
- Cedar Grove, Wi-Sheboygan
I upgraded a section of my duct work which are original to my house or I should say the equipment of over 30+ years and believe it or not there wasn't alot of anything in my duct work to speak of. This also includes the duct work not being sealed until just this past winter where there were many leakage points thru out the entire trunk and supply runs so there wasn't much of anything not even build up or dust piles along any point from the plenum to the last ft. of duct work.
I will mention that after sealing the entire duct system I haven't had as much dust in my house and only really need to dust maybe every other week at most. And if I didn't have my Pomerania who drops hair when he walks thru out the house I wouldn't have to run my swifter sweeper around the house everyday.
IMO it is probably best to leave the duct work alone unless there's real evidence of problems such as mice, construction dust, or other issues where there really needs to have the duct work opened up and disturbed.