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victor farr Posted: Aug 02, 2007 10:51 AM	closed cell over insulated duct work originally in my home (slab ranch) i had a central return air. When i converted the house from electric to gas, i had return air ducted thru the attic to provide better air flow. Im going to vac out my blow-in glass insulation and have closed cell applied to the back of the ceiling surface. Can I /should I consider having some foam applied over the return air duct surfaces? they have a layer of insul-board on them, but the more the marrier, right?
philip mullins Posted: Aug 02, 2007 03:54 PM	yea dustybone, i would definantly spray them. and i would expect it to work awsome. and it is my understanding that the codes have recently been revamped allowing this technique in residential applications. and you may want to research the unvented attic system. converting to an unvented attic,imho, is the way to go. many benefits.
victor farr Posted: Aug 02, 2007 05:27 PM	i figured the more insulation on the ducting the better. as for the conditioned attic space, im not 100% sold. it would essentially double the square footage my HVAC systems currantly have to condition. I dont need the space for storage or anything, so im just not sure why heat/cooling more area is a benefit. if i can seal the envelope with 5-6" of CC foam at the ceiling level and PROPERLY vent the attic, it just seems that would save even more on heating/cooling costs? i could be wrong...
Terry Adams Posted: Aug 03, 2007 09:53 AM	What part of the country are you in?
victor farr Posted: Aug 03, 2007 10:15 AM	ohio
philip mullins Posted: Aug 03, 2007 12:27 PM	is that terry from nexgen?
Gerry Wagoner Posted: Aug 03, 2007 05:56 PM	An attic envelope acts as a buffer for the living space, while providing a controlled climate for the HVAC lines. The "conditioned attic" is passively conditioned in most cases and needs no direct duct register to act upon it. We find that conditioned attics stay within 7-8° of the living space. That is much better than the 142° swing that most of our attics experience in Ohio. Olger Piqua, OH
Terry Adams Posted: Aug 03, 2007 11:47 PM	yep, curious about the depth of foam being sprayed.
philip mullins Posted: Aug 04, 2007 11:31 AM	terry, been meening to touch base with you, since we're nieghbors. just been to darn busy. i'll be working tomorow most of the day but, expect a call soon.
victor farr Posted: Aug 04, 2007 04:41 PM	BHI and i have talked at length about the best solution, and foaming the ceiling surface was his recomendation. I have spoken with 2 other customers he did similar jobs for and they were beyond pleased with the results. r-40 (which was 5 1/2" of foam i believe) is what he proposed. Even with passive conditioning, energy dollars are lost, correct? i mean, i dont have registers in my walk-in pantery or closets, but if you eliminated the square footage from the home, there would be a realized savings in HVAC bills. or am i way off base here? im not trying to raise agrument here, im just trying to get ALL the info before i put out a faily large investment in reinulation my home. i worked in the HVAC industry (on the control design/wholesale end) so i am minorly familiar with the mechanics of conditioning spaces, its the insulation thats the mystery to me. if the 'buffer' t******ry is the basis, then why not insulate ALL attic surfaces and get the benefit of keeping the house insulated from the attic as well as insulating the attic to serve as a buffer? i suppose you would lose the passive conditioning, but with a push-pull 2-fan vent system it would seem that would be the ideal solution.

Author

Comments

victor farr

Posted: Aug 02, 2007 10:51 AM

closed cell over insulated duct work

originally in my home (slab ranch) i had a central return air. When i converted the house from electric to gas, i had return air ducted thru the attic to provide better air flow. Im going to vac out my blow-in glass insulation and have closed cell applied to the back of the ceiling surface. Can I /should I consider having some foam applied over the return air duct surfaces? they have a layer of insul-board on them, but the more the marrier, right?

philip mullins

Posted: Aug 02, 2007 03:54 PM

yea dustybone, i would definantly spray them. and i would expect it to work awsome. and it is my understanding that the codes have recently been revamped allowing this technique in residential applications.

and you may want to research the unvented attic system. converting to an unvented attic,imho, is the way to go. many benefits.

victor farr

Posted: Aug 02, 2007 05:27 PM

i figured the more insulation on the ducting the better.

as for the conditioned attic space, im not 100% sold. it would essentially double the square footage my HVAC systems currantly have to condition. I dont need the space for storage or anything, so im just not sure why heat/cooling more area is a benefit. if i can seal the envelope with 5-6" of CC foam at the ceiling level and PROPERLY vent the attic, it just seems that would save even more on heating/cooling costs? i could be wrong...

Terry Adams

Posted: Aug 03, 2007 09:53 AM

What part of the country are you in?

victor farr

Posted: Aug 03, 2007 10:15 AM

ohio

philip mullins

Posted: Aug 03, 2007 12:27 PM

is that terry from nexgen?

Gerry Wagoner

Posted: Aug 03, 2007 05:56 PM

An attic envelope acts as a buffer for the living space, while providing a controlled climate for the HVAC lines. The "conditioned attic" is passively conditioned in most cases and needs no direct duct register to act upon it. We find that conditioned attics stay within 7-8° of the living space. That is much better than the 142° swing that most of our attics experience in Ohio.

Olger
Piqua, OH

Terry Adams

Posted: Aug 03, 2007 11:47 PM

yep, curious about the depth of foam being sprayed.

philip mullins

Posted: Aug 04, 2007 11:31 AM

terry, been meening to touch base with you, since we're nieghbors. just been to darn busy. i'll be working tomorow most of the day but, expect a call soon.

victor farr

Posted: Aug 04, 2007 04:41 PM

BHI and i have talked at length about the best solution, and foaming the ceiling surface was his recomendation. I have spoken with 2 other customers he did similar jobs for and they were beyond pleased with the results.

r-40 (which was 5 1/2" of foam i believe) is what he proposed.

Even with passive conditioning, energy dollars are lost, correct? i mean, i dont have registers in my walk-in pantery or closets, but if you eliminated the square footage from the home, there would be a realized savings in HVAC bills. or am i way off base here?

im not trying to raise agrument here, im just trying to get ALL the info before i put out a faily large investment in reinulation my home. i worked in the HVAC industry (on the control design/wholesale end) so i am minorly familiar with the mechanics of conditioning spaces, its the insulation thats the mystery to me.

if the 'buffer' t******ry is the basis, then why not insulate ALL attic surfaces and get the benefit of keeping the house insulated from the attic as well as insulating the attic to serve as a buffer? i suppose you would lose the passive conditioning, but with a push-pull 2-fan vent system it would seem that would be the ideal solution.

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