# JM Mineral Wool Question



## Bud9051 (Nov 11, 2015)

The number you show for the industrial implies 24" wide and only 2" thick. You can't compare the price of that to properly sized insulation for 16" on center walls. Insulation is all about proper fit and thickness.

For the residential it is indicating R-4.3 per inch (15 divided by 3.5"). I suspect the industrial R per inch is similar, thus no advantage. Plus you will have waste from length, width, and thickness, PIA.

Bud
BTW welcome. And Roxul was one of the first mineral wool products and I have used it and like it. Availability is good where I live.


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## tigers04champs (Oct 19, 2017)

Thanks Bud,

Yea, I was doing a little more research last night on it and it seems the residential one is the better route, just double the price. I just didn't want to insult my friend who used the industrial one on his house. He has a 3700 sq ft house, and there electric bill is under $150 a month in South Louisiana, which is pretty impressive for that size with the heat of the summer. 

I was looking at the Roxul as they have way more availability of it down here compared to the JM. Do you know if there's any big difference between the Roxul and JM? 

Thanks again for your help. This is my first self build house, so one of those learn as you go things.


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## Bud9051 (Nov 11, 2015)

Is the industrial half the price because it is half as thick, 2" vs 3.5"?
Not familiar with the JM mineral wool product but have only heard good about Roxul. We use a long bread knife to cut it.

Note, one aspect they all agree with is that air sealing is a significant contributor to lower energy costs. Being a new home a couple of cases of caulking will have a major payback for you. There are other factors that go along with a tight home but all are manageable, just necessary. When a house doesn't leak you need to add fresh air, but you get to choose where it comes in. Long topic.

Being in a southern climate, if your ac and or ducts are in the attic make sure all are sealed and extremely well insulated. Most hvac installers will tell you the simple wrap is fine and it will work, just increases your bills.

My first "learn as you go" was 1968, used a GC and paid attention. BUT we didn't have forums like this or the internet. It gets in your blood.

Bud


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## tigers04champs (Oct 19, 2017)

I'm assuming it's half the price because of that. Here's a link to the JM at Lowe's:
https://www.lowes.com/pd/Johns-Manville-49-7-sq-ft-Unfaced-Mineral-Wool-Batt-Insulation-with-Sound-Barrier-15-25-in-W-x-47-in-L/1000164881

I'll probably just go with the Roxul, I was just nervous because no one I know has used it down here before. However, I hate fiberglass, and I'm not paying for foam, so not many other options here. I do love how the installation seems a whole lot easier than fiberglass.

Thanks for the HVAC tip. It seems they all have their own opinion and none of them are the same. :vs_worry: 

Yea, I don't know what I would do without forums and the internet. That's all I've been doing. Reading everyone's past experiences and tips. I work in IT, and not the best handyman. I know just enough to screw stuff up.


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