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Cellulose vs. Fiberglass blow in insulation

hotrod1131's Avatar

Join Date: Oct 2007
Posts: 11

10-22-07, 11:41 AM   #1  
Cellulose vs. Fiberglass blow in insulation

Opinions anyone - I have a attic that has some cellulose blow in insulation and I want to add more blow in insulation. Should I blow in fiberglass insulation or cellulose insulation?
I live in Montana and need another 6-8 inches. Does fiberglass insulation settle better than cellulose insulation.


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adamplghtg's Avatar

Join Date: Mar 2007
Posts: 450

10-22-07, 02:02 PM   #2  
I don't know what you mean by "does it settle better" but cellulose is far superior to blown-in fiberglass(and normal batts for that matter). Look at this page: <a href="http://cellulose.org/pdf/cellulose_benefits/cons_report4.pdf">Performance and Safety</a>. It focuses mainly on cellulose and blown-in fiberglass.

Here are some quick facts:

- Blown-in fiberglass looses some of its R-value as it gets cold out. It looses almost 15% at 20F(thats positive, not negative)
- Fiberglass does a crappy job of controling air infiltration(air movement).
- Blown-in fiberglass has a R-value of about 2.2 per inch. Cellulose is about 3.6.
- Cellulose is fire resistant. Fiberglass is noncombustible BUT it does melt. When it melts, it creates a hole for the fire to escape thorough. Cellulose won't create a hole for it to escape through. It will hold it in its place far longer than fiberglass can dream too.
- Cellulose is a green product. It contains about 80% recycled material. It also takes a lot less energy to produce cellulose than fiberglass.

Concretemasonry's Avatar

Join Date: Mar 2005
Posts: 6,125

10-22-07, 02:39 PM   #3  
Cellulose vs. Fiberglass blow in insulation

No question - Cellulose is much better in every way!!


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