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.

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.

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.

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.

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

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.

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

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

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

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

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

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?

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.

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.

We looked at a 100yo house, but settled on a 50yo because the construction materials were things I could recognize, and wouldn't be afraid to tear apart without knowing how to put them back together. Some friends of ours ended up buying the 100yo place we looked at. We're in a nice little historical district where one house may have goats in the yard and the next may be a huge, old mansion. And then there are street like mine, i.e. Pleasantville. Our neighbors are little old ladies--it's like having a free burglar alarm.