best way to seal duct system

[printmanjackson]

I hope that even though this is a DIY question ...."that anyone can do that has even half the ability", that this thread won't get canned and we HO's can get some good information from all the Pros here.

I'm sure most of the HO's that come on this site are more than just the common person anyway.

What's the best way to seal up the duct system?

How can you tell you have everything sealed properly?

I'm sure something as simple as this can make any sysytem work better at the least. Most of the common people like me own a home with a system that was installed by less than "preffered" installation "professionals".

We need things to look for on solid duct systems and flex systems to help improvements.

[hvacrmedic]

Mastic tape. For more energy saving tips you can vist

http://www1.eere.energy.gov/consumer/tips/

[dan sw fl]

How can you tell you have everything sealed properly?

http://www.energystar.gov/index.cfm?...rovement_ducts

Testing:
1. Duct blaster
2. Blower door for house leakage

1. http://www.southface.org/web/resourc...22blowdoor.pdf

2. http://www.infiltec.com/inf-btst.htm

[big johnson]

Mastic tape. For more energy saving tips you can vist

http://www1.eere.energy.gov/consumer/tips/

Hey Medic, pardon my ignorence, but what is mastic tape? I've used mastic and I've used tape, but have never seen the 2 in one product.

[cem-bsee]

apply HVAC mastic = thick paste, available @ 'big box' stores -- to all seams & joints of ducts & plenums [ boxes ]
somewhat messy -- Goop hand cleaner removes

[Shophound]

apply HVAC mastic = thick paste, available @ 'big box' stores -- to all seams & joints of ducts & plenums [ boxes ]
somewhat messy -- Goop hand cleaner removes

I prefer this over "mastic tape". If you're not bad with a paint brush, the mastic can actually look somewhat neat when applied.

For the OP, possibly the most neglected component of duct sealing is where the register boots meet the building drywall. Especially if that boot is adjacent to an unconditioned, ventilated attic. You could effectively seal all other components of the duct system (supply and return plenums, wyes, 90's, 45's, etc.), but leave this gap unsealed and the stack effect of escaping air from the house into the attic is considerable...and costly.

[printmanjackson]

>In a typical house, however, about 20 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts.<

wow! 20% is alot to loose!

This is great information!
here is the link to this site if anyone missed it
http://www.energystar.gov/index.cfm?...rovement_ducts

[hvacrmedic]

Hey Medic, pardon my ignorence, but what is mastic tape? I've used mastic and I've used tape, but have never seen the 2 in one product.

Shurtape AF-100 or SF-685
http://www.shurtape.com/Portals/0/EU.../AF_100_EU.pdf
http://www.shurtape.com/Default.aspx...6&ProductID=98

Once you try it you'll never use paint-on mastic again.

[big johnson]

Shurtape AF-100 or SF-685
http://www.shurtape.com/Portals/0/EU.../AF_100_EU.pdf
http://www.shurtape.com/Default.aspx...6&ProductID=98

Once you try it you'll never use paint-on mastic again.

How does it work for sealing transitions on the inside of the duct with a sound barrier @ 140* supply air temp?

[air2spare]

>In a typical house, however, about 20 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts.<

wow! 20% is alot to loose!

This is great information!
here is the link to this site if anyone missed it
http://www.energystar.gov/index.cfm?...rovement_ducts

I think its closer to 30% on average for an unsealed duct system

[hvacrmedic]

How does it work for sealing transitions on the inside of the duct with a sound barrier @ 140* supply air temp?

Even better when heated. You will NOT get this tape back off again after it's been heated to 140º.

[Swampfox]

AF-100 is not mastic tape

Mastic tape works great on metal, wont stick to ductboard very long at all

[howard33]

What about Aeroseal:
http://www.aeroseal.com/

Does this work?
Seems like it would really, really, really depend on the tech doing it.
Anyone with experience where this was used?
thanks,
howard