Green Insulation Types
 

What have you guys found to be the greenest insulation types? There is conflicting information about fiberglass online. It's one of the most used types, but some say it poses health risks. Others argue that it is recyclable and therefore, green.

Is there an insulation type that is universally recognized as eco-friendly?

Thanks!

IMO cellulose is pretty eco-friendly.

Spray foam makes a structure more air tight.

So you want environmentally friendly insulation or the best insulation that will reduce fossil fuels use for heating the most?

Thanks for your replies and suggestions. I was really meaning something that isn't harmful to the environment to produce, but both points are important.

If the insulation is going to be used for 30 to 50 years environmental impact of its creation is nothing compared to burning more fuel for that entire time.

Thanks; that's a really valid point! Spray foam is what you'd recommend?

Spray foam us kind of a double edge sword.
It can actually seal up a building too well when applied to everything on a wood frame building.
I say at least use the $5 spray can around doors and windows minimum to seal up gaps.
You should be able to do interior walls with spray foam if you want some sound deadening between room.
Spray foaming roofing may not be ideal. I would only do it under a metal roof.
The way I have done it on exterior walls I always put fiberglass between the window to floor. Just assume it's going to get wet, fiber glass won't rot and it can breath a little. I always use pressure treated around windows and doors. If the window is tucked nicely up under the eve I will spray foam up to the window or door frame. If the window or door is exposed by a high roof line I will fiberglass one stud out on both sides of the windows and doors incase it gets wet, which it will.
I spray foam around all exterior light junction boxes, it seals out the wind and bugs.

If your structure is all masonry, spray it by the truck load since it's already sealed up like a tomb and probably very water tight.

Thanks for all the info and detailed advice! I will take this into consideration.

Another disadvantage of spray foam is the sealing action and complete filling of cavities. If you ever want to renovate, the electric and plumbing runs are sealed in a solid block of foam. It's not impossible to work on the stuff inside the block, but it should be considered as a permanent component that cannot be modified after being sprayed. For this reason, most contractors do not completely fill up wall cavities.

Blown in cellulose insulation is very close in performance to spray foam insulation inside cavities. The difference between the two depends on how stringent your requirements and specs are. Spray foam is absolutely a vapor barrier, where cellulose is somewhat of a vapor barrier. When properly applied, spray foam absolutely does not breathe, or allow any infiltration of air, where cellulose allows a miniscule amount of air and vapor to pass through. With enough pressure applied, cellulose will breathe 50 to 60 percent more air than spray foam. This relates to 0.2 air changes per hour vs 0.3, so 50 percent more than nearly nothing is still almost nearly nothing.

Probably the three most important factors to consider are fire safety, cost, and "eco-greenness". Cellulose is a winner by a landslide in all three categories. Cellulose is classified as a fire retardant material, where spray foam requires a fire barrier around it (because it can burn violently and release toxic vapors). Spray foam costs two to three times the price of cellulose, plus you get a cavity that is not completely filled (which short changes you from some insulating value). On the eco-friendly green factor, cellulose is 85 to 90 percent recycled paper, where spray foam is 100 percent refined petroleum.

I chose rock wool for my attics. Much safer for humans and a better fire and sound suppressant.