Insulation: Part 1 – Green or Greenwashed?

PIC foam with aluminum facing Credit:

The good, the bad and the truly ugly truthiness of insulation.

Glass Fiber Insulation

Fiberglass insulation

Glass fiber insulation is made or glass, new or recycled, and held together with binders.  It is cheap and non-combustable.  But it’s far from perfect. It has a relatively low R-factor and there are considerable concerns about the product’s impact on our health and the environment.   There’s a yuk factor.  Ask anyone who has gotten into the guts of an old trailer and they’ll gross you out with tales of what they uncovered in the insulation: rat’s nets, bug bodies, etc. Got leaks?  When rain and snow seeps into fiberglass, insulation turns into a soggy, moldy mess.  There are the considerable health concerns:

If you have ever worked with it you know how it makes your skin itch; imagine it in your lungs. Some have claimed that it is the next asbestos and is cancer-causing; one website calls it “The Asbestos of the 21st Century. Packages of insulation carry cancer warning labels, based on a 1998 study. However the American Lung Association lists the studies and the most recent ones conclude that “It is currently considered not classifiable as a human carcinogen. Studies done in the past 15 years since the previous report was released, do not provide enough evidence to link this material to any cancer risk.”  – Planet Green

What are the alternatives?  Here are some types of insulation that are more or less “friendly” to the environment.



Hemp insulation is made from hemp fibre with polyester added for strength.  Soda is added as a fire retardant.  Hemp is naturally resistant to moths and beetles. Hempflax (it comes in bats) is manufactured by a Dutch company that claims their product is low in dust which helps contribute to cleaner indoor air.  They say their product can be recycled after use.  The hemp comes from Germany and the Netherlands.  Imported.  See the company web site for a PDF brochure – and a mind-expanding history of industrial hemp (what is it about the Dutch and weeds?)



Denim insulation is mostly made of the leftover bits from blue jeans and treated with a “natural” fire retardant.  Bonded Logic is the company that makes UltraTouch Natural Fiber Insulation from 85% post-industrial cotton fiber. It is 100% recyclable, VOC- and formaldehyde-free. And it won’t itch like fiberglass insulation.  (Seems like there’s a lot of dust that comes out when you shake it. )

Recycled Newspaper

Recycled Newspaper

Excel Building Solution’s Warmcel  made from 100% waste recycled newsprint. Thermal conductivity of  0.036 W/mK. Said to be an alternative to blown fiberglass or bat insulation. layered into walls being built, or blown into atticspaces and already sheetrocked. Warmcel insulation by Excel



Water-blown policynene that creates an foam blanket of millions of tiny air bubbles. It does not shrink and adheres to the surrounding structure, so there is no settling and no air gaps. It has no VOC’s no formaldehyde, Recognized for LEED credits and is becoming very popular as a clean, green, long lasting insulation. When holding a piece, it seems the most benign and friendly insulation ever, it is like filling your walls with sponge cake. ::Icynene




Procell is a mix of 100% recycled newspapers, adhesives and fire retardants that fills voids and dries quickly, and appears similar to Dom’s Warmcell from the UK.  Pro-Cell is “specially treated to repel vermin and insects, and to prevent the growth of harmful mould, mildew and wood-rotting fungi” “::Thermocell



This is a polyurethane foam system made out of recycled plastic (a barrel of Heatlok-soya contains 1000 plastic bottles) and soya oil.  zeroozone depletion and is even coloured green. The manufacturer, Demilec, “is the first Canadian manufacturer of Spray Polyurethane Foamto meet the requirements of the Montreal Protocol. DEMILEC uses recycled plastics, renewable natural oils, and water, all while maintaining the high quality and performance of its foam systems. ::Heatlok Soya


Aspen Aerogels has started selling aerogel blankets for use as insulation in buildings.

“Aspen Aeorgels says that its Spaceloft blankets have two to four times the insulating value per inch compared to fiberglass or foam. It’s also relatively easy to work with, allows water vapor to pass through, and is fire resistant–a common demonstration of aerogels is to have a person fire a Bunsen burner below the aerogel while putting a hand on the top side.” (source)

The fact that it’s just 2 to 4 times better than fiberglass or foam makes me think that they paid a pretty big performance price to bring costs down, since pure aerogel would provider higher thermal insulation, but it’s still a pretty big step in the right direction. We’re not talking about a few percent improvement. Over time, in a big building, this could represent a lot of heat that would otherwise leak out (or heat that would leak in when the air conditioning is on).

Other companies that are coming out with more affordable aerogel derivatives to be used as building insulation are Cabot and Thermablok.

I wouldn’t be surprised if in a few years (or decades at most) very high-quality aerogel was used almost everywhere for insulation. Unless we make something even better, that is.

Other types of insulation such as straw bale aren’t appropriate for trailers.

Some Links:

“Green Insulation: More Choices”

“Why the choice of insulation matters”

” Space age insulation: it’s already here”

This post is part of a series documenting Sam Breen’a Spartan Restoration Project. Please see his first post here and check out the archive here. The CSPA is helping Sam by serving in an advisory role, offering modest support and featuring Sam’s Progress by syndicating his feed from as part of our CSPA Supports Program.