Attic insulation differences

The specs say the R value is higher on the more expensive one. That's all I saw.

Can I ask why cellulose? It settles and it’s nasty dusty. The blown in fiberglass stuff has a higher R-value, doesn’t settle and doesn’t have all the nasty dust. It does itch like a mofo if you get it on you, though.

You get a free machine for the other bags and also the R value per square inch is the same for both according to the specs

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Literally every website/video says cellulose is the superior product so that's why I'm choosing it

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Do they say why? I know that it settles, which is not true for fiberglass batts. The cellulose or fiberglass itself does not provide the insulation; it's the trapped air in either. As insulation settles, it loses that air and becomes less insulating.

But cellulose has been in favor for some time now, so I can't imagine it's a bad choice.

ETA: Did a little looking and ere is what I found out.

Cellulose Insulation:

Higher R-value: Cellulose typically has an R-value of 3.2 to 3.8 per inch, while fiberglass is usually between 2.2 and 2.7 per inch, according to Nu-Wool Premium Cellulose Insulation.

Better Air Sealing: Cellulose's density allows it to fill gaps and cracks more effectively, minimizing air leaks and drafts.

Eco-Friendly: It's often made from recycled materials (like newspaper), making it a more sustainable option.

Potential Settling: Cellulose can settle over time, which may reduce its effectiveness.

Dusty Installation: Installation can be messy and dusty.

Moisture Sensitivity: Cellulose can absorb moisture, potentially leading to
mold growth if not properly installed or maintained.

Fiberglass Insulation:

Easier Installation: Fiberglass batts are readily available and relatively simple to install, especially for DIY projects.

Lower Cost: Fiberglass is often more affordable than cellulose, both in terms of materials and installation.

Moisture and Mold Resistance: Fiberglass is naturally resistant to moisture and mold.

Lower R-value: Generally, fiberglass has a lower R-value per inch compared to cellulose.

Potential for Air Leaks: Fiberglass batts may not seal air leaks as effectively as blown-in cellulose.

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Cellulose typically has an R-value of 3.2 to 3.8 per inch, while fiberglass is usually between 2.2 and 2.7 per inch

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True when freshly installed, but not after the cellulose settles. The quote also compares blown in cellulose to fiberglass batts. Kind of apples v oranges.

Cellulose isn’t a bad product. It’s been used for a long time. The blown in fiberglass is just superior in this climate.

Correct. The R-value per inch is lower for the fiberglass, but, again, that’s before accounting for settling. My issue with the quote is the source seems to be comparing blown in cellulose to batt insulation and air sealing. That’s where my apples v oranges comment comes from.

If OP insists on cellulose, I’d use 150% of the final depth, then you’ll have no worries, assuming there are no potential moistire or rodent issues.

I just had cellulose T-A-P insulation blown in on top of old blown in fiberglass and it immediately improved the interior comfort of the home. I am no longer a skeptic.

The cellulose is by far a better product than the fiberglass. With cellulose, the R-value is higher, the sound dampening is MUCH better and it is much cheaper.

Production of the cellulose is probably 10X less expensive than fiberglass, which is likely why it is cheaper.

And the fiberglass is nasty stuff.

Put down Johns Manville 9 inch R 30 unfaced on attic floor.

Since the attic is floored, I ordered the 23 inch wide rolls rather than 15 inch rolls.

Not batts