Blown Insulation: Cellulose vs Fiberglass

[Andrew Thuswaldner]

I've had two contractors visit and give me a quote on upgrading my bungalow attic insulation from R20 to R50. The first contractor would blow in the fiberglass insulation. He says the cellulose is junk. The second contractor would use cellulose. He said that the blown in fiber glass is "basically garbage". I am obviously not getting an objective view from these contractors. Can anyone comment on the performance and long term viability of these two products?
thanks,
Andrew

[phil harold]

Loose fill blown fiberglass insulation has problems. As the temperature difference between the living space and attic increases, the R-value of blown fiberglass diminishes. In extreme situations, the reduction in R-value approaches 50 percent.
Fiberglass allows more air movement and
fiberglass can lose 40 -70% of its r-value if moisture vapor enters the system

cellulose settles more than fiberglass

I would go with a thick layer of cellulose in a cold climate

[brian watson]

We have blown cellulose in our attic over the garage. I highly reccomend it. I use the garage as my shop and it has made it possible to use it in the winters. Granted you're probably a little colder up north but it made a huge difference here in Nebraska

[Louis Brandt]

We just added several inches of blown-in cellulose to our attic, including the portion over the garage. We did a lot of research and decided on the cellulose.
Louis

[Chris Rosenberger]

I prefer cellulose insulation for all of the reasons stated above. The fiberglass industry has started a big advertising campaign for blown fiberglass. That is why everyone says it is best. Air will flow through fiberglass insulation. A lot of furnace filters are made out of woven fiberglass.

[Stephen Tashiro]

What is blown fiberglass insulation like to work around? (For example, suppose you decide to put in a new light fixture.) I recall a summer job of installing "bats" of fiberglass insulation under a floor in a crawlspace. It was very uncomfortable to get those fibers all over you. Of course, that was in the 1960's. Maybe the bats are different now.

[Matt Meiser]

The contractor I had quote doing my attic said he would do fiberglass but recommends cellulose because of the performance.

[David G Baker]

My pole barn has 14 inches of blown in cellulose and it has preformed quite well for me for the past 6 years.
If I use fiberglass it will be in rolls or bats.
If I add more insulation to my house, under the floors I will use heavy spray foam, the walls the lighter spray foam and the attic will have more blown in insulation added.

[Chris Damm]

According to a report I read years ago 1% moisture cuts the R value of fiberglass in half. Of the 2 I would use cellulose, however I have been using closed cell foam with excellant results (cut a $400 heating bill to $40), but it's hard to retrofit in an attic.

[Cliff Rohrabacher]

Get Foam and put them both to shame.

There's nothing quite so effective and long lasting as a good blown in foam.
No settling, great R factor.

[Dick Strauss]

I'd go for blown in cellulose...it is easily installed by homeowner (free blower loan if you buy a certain number of bales at BigBox stores), it's cheaper per R-value, it's a good insulator for a cold climate and it's not as nasty to deal with as fiberglass is. I'll be using cellulose when I get off my duff later this year.

I was recently quoted $2.20/sq ft of surface area for expanding open-cell foam. This amounted to $8k for an 1800 sq ft home for the foam. My return on investment would be at least 20 years so it is no longer an option.