No radiant barrier insulation is good in Midwest?

strategery

I live in the mixed climate of Iowa. I was talking to an energy auditor a couple of months ago and I asked him if it would save me money to put a radiant barrier foil on top of my attic insulation. He said emphatically NO. He told me that he spends a great deal of time taking those OUT of attics here in this climate zone because they trap moisture which leads to mold in the attic and subsequently in the rest of your home.

Is this true? Anyone have experience or opinions on this?

spaceboy

I am no expert on this - but have been researching this product myself.

I think that there are a total of 4 different versions of this product:
- Aluminum Perforated
- Aluminum Solid
- Metalized Perforated
- Metalized Solid

The make up of the product between Aluminum and Metalized are different based on fire rating (this makes NO sense to me... but metalized burns quicker and is the product you need to meet code these days).

Aluminum blocks 97% of radiant heat and Metalized blocks 95% - not much different.

The solid version of this product acts like a vapor barrier - that would be the only reason why i think he would suggest removing it. Through all the research I have done - perforated is the way to go for an attic as to not trap moisture.

That's what I know... hope it helps.

Windows on Wash

Radiant barriers are statistically insignificant if there is a proper insulation layer.

I would make sure you insulation is adequate and skip the radiant barrier.

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HomeSealed

Exactly.
I cannot speak to their effectiveness in other climates, but they are wasted money in the midwest. Airseal and insulate for optimum performance.

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strategery

What level of insulation do I need in Iowa? What kind? I read a lot of confusing information about fiberglass vs cellulose.

HomeSealed

I'd assume that you are the same as WI, so the code is R49, although ideally you'd like to be around an R60. Cellulose is generally preferred by most pros and experts, but fiberglass can be done effectively as well. What is the existing material.... The one thing that is absolutely crucial is air-sealing prior to adding the additional insulation if you've not yet had that done.

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Windows on Wash

R-50 minimum.

It is cheap to add additional once they are already up there.

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strategery

I had an energy audit done last spring and the same company I hired to seal off my attic flooring to prevent air leaks into the attic.

The same company however spray-foamed my basement rim joists and after close inspection they missed a couple of small spots. They have fixed it every time I have called them but it still leaves open the possibility that they didn't get the attic seal job done properly.

I currently have have about R-30 which I need to bring up. I need to blow in some cellulose I guess.

HomeSealed

Sounds like you are on the right track.

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Windows on Wash

It is not uncommon for foam to pull away from a wall depending on a formulation or contributing factors.

Depending on the nature of the spots, I may not hold it against them.

All air sealing work that we do is performance tested (before and after blower door testing) for effectiveness.

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