Duct sealing?

[Guest guest]

Hi Kathy,

I have found your letters interesting, starting with the window issue,

progressing to the ducts. I wonder if the ducts are the problem, and not the

windows. New windows seal far better than the old, and thus amplify any indoor

air quality problems you might have.

I am really curious about the duct sealing you are mentioning. Why is it

recommended? Ducts can be a big problem if old and leaky, or simply if not

properly installed. Attic flex duct gets very hot in summer, and the inner

plastic lining can degrade. Sealing is not the answer. Replacement is. Also,

does this system have a plenum made of fiberglass ductboard, or have some other

type of inner fibrous insulation? If so, replacement of the plenum is highly

suggested. Sheet metal plenum and ducts are suggested, possibly with a little

flexduct at the ends to connect to existing registers. All insulation should be

on the outside of ducts. For extra protection against biofilm formation, you

might want to pay the added cost for AK Steel's Agion Technology metal ducts.

VaporBarrier/Ventilation

Posted by: " baahstun@... " baahstun@... baahstun

Date: Mon Jan 31, 2011 6:35 pm ((PST))

Hi Carl/Jeff/-

This house is a retrofit thus I have both electric baseboard and the forced air

furnace is in the attic. The house is on a slab, no basement. I do not run the

a/c, just the heat. But because our winters are so long, the heat runs from

Sept/Oct through May/June. IAQ guy hooked me up w/local HVAC who came in and

did some duct testing (I have flexible ducts) and some other stuff so we could

start exploring options. His final options were everything from heavy duty

construction type stuff all the way down to simply adding filtration to the

furnace. But everything that may utilize my ductwork necessitates that I first

seal the ducts. Rec'd his recommendations late October, never a good time for

an MCS person to be doing anything that involves the interior of their home. So

whatever I do, is going to have to wait till this spring. So threw in some

SafeHomeDuos in the furnace and started the search for portable air cleaners to

try

and get me through till spring.

Can I also ask your expertise on duct sealing? The HVAC guy is Aeroseal

installer and although gasping at the MSDS, kept an open mind and requested a

sample. The sample I received is in a 3 month solid state and is such a toxin

to my body that I left it outside. No need to do the sleep test with that one,

for sure...lol... Rats cause the idea of going with an interior blown sealant

seems much more effective than trying to accomplish the same w/visual manual

exterior sealing using a water based mastic. Do you guys know of any duct

sealers I should consider?

Thanks

Kathy