Radiant Barrier/ insullation Delima

Pooka · 06-20-2008, 01:39 PM

Hello Folks!
I am researching ways to improve our energy efficiency here and have decided that the most immediate need with the Texas heat is more insulation. I should mention that our A/C Ducts run through our attic which is about 4 feet high... in other words the temperature of our air is raised considerably by the outside heat.

To alleviate some of this I plan to increase the attic insulation to anywhere from R38 to R49 and in addition I'd like to go with a radiant barrier. Here is where I'm torn. The foil variety will give in (in theory that is) a 97% reflectivity witch is excellent, however it can't be installed in an existing home all the way to the roof line and so you loose some of that 97% which matters considering the cost if greater than the spray on "paint" variety. The Heat-Block 75 seems to be the highest functioning of the spray on varieties it has a reflectivity of 75%, but because you can use a long narrow sprayer it will cover completely and all 75% will be retained. At least this is what I've been told.

As for insulation I wanted cellulose (the recycled variety... just trying to go as green as possible) but I have found that the cellulose contains Formaldehyde as a fire retardant and I'm really not keen on the idea of that being in our house especially being that I am very allergic to it... couple that with the fact that cellulose can mold and even with the retardants burn...and fiberglass is looking more appealing to me. There is a type called Jet Stream 73.3 which is not as irritating as the shaved fiberglass... and it is non-combustible, doesn't support microbial growth and won't rot mildew or deteriorate. So I'm thinking this is what we'll go with... and I'm leaning more toward the R49 simply because we have an old 10SEER A/C and it is MUCH cheaper to insulate than it is to replace that unit(which will be replace for a small service fee by our home warranty when it finally gives up the ghost).

What is your experience with any of these products or types of products? I'd like to have some feedback from people who actually have them before I write a check. The ultimate goal is to reduce our bill and make our home more comfortable at the same time.

glatt · 06-20-2008, 02:11 PM

You would have better luck going to the discussion forum at the Fine Homebuilding website. They have building experts there who will give you decent information. You have to register, but it's free, and valuable.

Griff · 06-20-2008, 02:14 PM

I can tell you that Reflectix (radiant barrier) is an easy install but I second the Finehomebuilding site if you want to know about its usefullness.

Flint · 06-20-2008, 02:19 PM

Pooka is my lovely wife, and mother of my two amazing children; in case you didn't know. So I can't help but feel responsible for our house being full of "hot air" if you know what I mean--waka waka! But the main problem is that spellcheckers haven't been invented yet in Texas.

Griff · 06-20-2008, 02:24 PM

If my responding in some way causes you to spend a hot summer day crawling in your attic, I humbly ask for your forgiveness.

lookout123 · 06-20-2008, 02:29 PM

you don't really think flint would make the beautiful mother of his darling children crawl through the attic on a hot texas summer day, do you griff? think of the children flint. the children.

Griff · 06-20-2008, 02:49 PM

Quote:

Originally Posted by lookout123

you don't really think flint would make the beautiful mother of his darling children crawl through the attic on a hot texas summer day, do you griff?

No. I was responding to flint. I fear the love of his life has an evil plan.

Pooka · 06-20-2008, 03:27 PM

Honey if you take issue with my spelling... you try writing anyrhing on here while supervising 2 in the tub and one on your shoulder...
I love you

I'll confess... Flint isn't the only one with a "hot wind"roblem... hahaha

Pooka · 06-20-2008, 03:34 PM

Make that Anything... and problem... yes spelling is clearly an issue

BigV · 06-20-2008, 03:36 PM

hey... you can edit your posts for a short time after submitting them. not necessary to make a whole new post.

BigV · 06-20-2008, 03:37 PM

Not that there's anything wrong with that...I'm just sayin.

tw · 06-20-2008, 03:39 PM

Quote:

Originally Posted by Pooka

I am researching ways to improve our energy efficiency here and have decided that the most immediate need with the Texas heat is more insulation. I should mention that our A/C Ducts run through our attic which is about 4 feet high...

Coolest part of your house is sitting all but exposed to hotest air. Essential is to construct a frame around those ducts and insulate the frame. This can be done with lathe and is best done with fiberglass insulation. Anything you do after that will be helpful. But the best insulation must enclose round those attic exposed air ducts.

Also consider fans for attic airflow?

footfootfoot · 06-20-2008, 06:13 PM

avoid fiberglass like the plague it is. The cellulose which we put in doesn't have formaldehyde (I wonder who told you that) it has boric acid as a fire retardant and insect retardant. Boric acid is what is used in eye wash. Very harmless unless you are a powder post beetle or termite.

You definitely want to wrap those ducts with as much insulation as practical. 2" foam blueboard is great stuff. you can put 4" of it on and you'll be all set. Jam it right up to the roof sheathing and use spray foam to fill any cracks. The key is eliminating any air infiltration/movement.

And remember while hot air rises, heat moves in any direction toward cold. Heat wants to give up its energy and moisture to cold. Heat is like that. Air, on the other hand goes up when it's hot and down when it's cold.

Pooka · 06-22-2008, 06:58 AM

Quote:

Originally Posted by footfootfoot

avoid fiberglass like the plague it is. The cellulose which we put in doesn't have formaldehyde (I wonder who told you that) it has boric acid as a fire retardant and insect retardant. Boric acid is what is used in eye wash. Very harmless unless you are a powder post beetle or termite.
.

Borates are great and I plan on lining the attic with it, but still the Formaldehyde concerns me... along with a few other considerations... here is a "green site" that discusses it:

http://www.greenbuilder.com/sourcebook/Insulation.html

"Cellulose insulation uses recycled newsprint that contains printers inks which can possibly outgas formaldehyde into a home. If there is any outgassing from inks, it should fall well below levels irritating most persons. However, an environmentally-sensitive person should be careful in selecting cellulose and install a vapor retarder between the insulation and the living space. (Note that the vapor retarder can exacerbate mildew problems if humidity levels in the house are high.)"

BrianR · 06-21-2008, 07:38 AM

You might also want to add soffit vents and a roof fan to let out the worst of the heat. I live in the asshole of Texas and I just bought a house that is 100 years old. I have a LONG list of things to do. I'd post pics and the video if I could find the wire to get them off my camera.

06-20-2008, 01:39 PM	#1
Pooka Your Invisible Rabbit Friend Join Date: Feb 2007 Location: Betwixt and Between Posts: 528	Radiant Barrier/ insullation Delima Hello Folks! I am researching ways to improve our energy efficiency here and have decided that the most immediate need with the Texas heat is more insulation. I should mention that our A/C Ducts run through our attic which is about 4 feet high... in other words the temperature of our air is raised considerably by the outside heat. To alleviate some of this I plan to increase the attic insulation to anywhere from R38 to R49 and in addition I'd like to go with a radiant barrier. Here is where I'm torn. The foil variety will give in (in theory that is) a 97% reflectivity witch is excellent, however it can't be installed in an existing home all the way to the roof line and so you loose some of that 97% which matters considering the cost if greater than the spray on "paint" variety. The Heat-Block 75 seems to be the highest functioning of the spray on varieties it has a reflectivity of 75%, but because you can use a long narrow sprayer it will cover completely and all 75% will be retained. At least this is what I've been told. As for insulation I wanted cellulose (the recycled variety... just trying to go as green as possible) but I have found that the cellulose contains Formaldehyde as a fire retardant and I'm really not keen on the idea of that being in our house especially being that I am very allergic to it... couple that with the fact that cellulose can mold and even with the retardants burn...and fiberglass is looking more appealing to me. There is a type called Jet Stream 73.3 which is not as irritating as the shaved fiberglass... and it is non-combustible, doesn't support microbial growth and won't rot mildew or deteriorate. So I'm thinking this is what we'll go with... and I'm leaning more toward the R49 simply because we have an old 10SEER A/C and it is MUCH cheaper to insulate than it is to replace that unit(which will be replace for a small service fee by our home warranty when it finally gives up the ghost). What is your experience with any of these products or types of products? I'd like to have some feedback from people who actually have them before I write a check. The ultimate goal is to reduce our bill and make our home more comfortable at the same time. Last edited by Pooka; 06-20-2008 at 03:19 PM.

06-20-2008, 02:14 PM	#3
Griff still says videotape Join Date: Feb 2001 Posts: 26,813	I can tell you that Reflectix (radiant barrier) is an easy install but I second the Finehomebuilding site if you want to know about its usefullness. __________________ If you would only recognize that life is hard, things would be so much easier for you. - Louis D. Brandeis

06-20-2008, 02:19 PM	#4
Flint Snowflake Join Date: Mar 2006 Location: Dystopia Posts: 13,136	Pooka is my lovely wife, and mother of my two amazing children; in case you didn't know. So I can't help but feel responsible for our house being full of "hot air" if you know what I mean--waka waka! But the main problem is that spellcheckers haven't been invented yet in Texas. __________________ **************** There's a level of facility that everyone needs to accomplish, and from there it's a matter of deciding for yourself how important ultra-facility is to your expression. ... I found, like Joseph Campbell said, if you just follow whatever gives you a little joy or excitement or awe, then you're on the right track. . . . . . . . . . . . . . . . . . . . . . . . . . . Terry Bozzio**

06-20-2008, 02:24 PM	#5
Griff still says videotape Join Date: Feb 2001 Posts: 26,813	If my responding in some way causes you to spend a hot summer day crawling in your attic, I humbly ask for your forgiveness. __________________ If you would only recognize that life is hard, things would be so much easier for you. - Louis D. Brandeis

06-20-2008, 02:29 PM	#6
lookout123 changed his status to single Join Date: Apr 2004 Location: Right behind you. No, the other side. Posts: 10,308	you don't really think flint would make the beautiful mother of his darling children crawl through the attic on a hot texas summer day, do you griff? think of the children flint. the children. __________________ Getting knocked down is no sin, it's not getting back up that's the sin

06-20-2008, 02:11 PM	#2
glatt ™ Join Date: Jul 2003 Location: Arlington, VA Posts: 27,717	You would have better luck going to the discussion forum at the Fine Homebuilding website. They have building experts there who will give you decent information. You have to register, but it's free, and valuable.

06-20-2008, 03:27 PM	#8
Pooka Your Invisible Rabbit Friend Join Date: Feb 2007 Location: Betwixt and Between Posts: 528	Honey if you take issue with my spelling... you try writing anyrhing on here while supervising 2 in the tub and one on your shoulder... I love you I'll confess... Flint isn't the only one with a "hot wind"roblem... hahaha

06-20-2008, 03:34 PM	#9
Pooka Your Invisible Rabbit Friend Join Date: Feb 2007 Location: Betwixt and Between Posts: 528	Make that Anything... and problem... yes spelling is clearly an issue

06-20-2008, 03:36 PM	#10
BigV Goon Squad Leader Join Date: Nov 2004 Location: Seattle Posts: 27,063	hey... you can edit your posts for a short time after submitting them. not necessary to make a whole new post. __________________ Be Just and Fear Not.

06-20-2008, 03:37 PM	#11
BigV Goon Squad Leader Join Date: Nov 2004 Location: Seattle Posts: 27,063	Not that there's anything wrong with that...I'm just sayin. __________________ Be Just and Fear Not.

06-20-2008, 06:13 PM	#13
footfootfoot To shreds, you say? Join Date: Aug 2004 Location: in the house and on the street-how many, many feet we meet! Posts: 18,449	avoid fiberglass like the plague it is. The cellulose which we put in doesn't have formaldehyde (I wonder who told you that) it has boric acid as a fire retardant and insect retardant. Boric acid is what is used in eye wash. Very harmless unless you are a powder post beetle or termite. You definitely want to wrap those ducts with as much insulation as practical. 2" foam blueboard is great stuff. you can put 4" of it on and you'll be all set. Jam it right up to the roof sheathing and use spray foam to fill any cracks. The key is eliminating any air infiltration/movement. And remember while hot air rises, heat moves in any direction toward cold. Heat wants to give up its energy and moisture to cold. Heat is like that. Air, on the other hand goes up when it's hot and down when it's cold. __________________ The internet is a hateful stew of vomit you can never take completely seriously. - Her Fobs Last edited by footfootfoot; 06-20-2008 at 06:21 PM.

06-21-2008, 07:38 AM	#15
BrianR Cleverly disguised as a responsible adult Join Date: Jan 2001 Location: Dallas, TX Posts: 3,338	You might also want to add soffit vents and a roof fan to let out the worst of the heat. I live in the asshole of Texas and I just bought a house that is 100 years old. I have a LONG list of things to do. I'd post pics and the video if I could find the wire to get them off my camera. __________________ Never be afraid to tell the world who you are. -- Anonymous

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