10 Green Insulations to Reduce Energy, Increase Comfort

The last couple of days have been unbearable with the wind chill below zero.  I can’t imagine what my house would feel like if we didn’t install several inches of open-cell foam insulation.  But what happens if you aren’t gutting your house and need to install insulation in certain areas of your house?  Listed below are green alternatives that I have discovered over the years.

A little background, please

Nine years ago, we built an Energy Star certified house.  The LEED for Home program wasn’t available.  In order to receive Energy Star certification, the home had to pass a blower door test, which required the house to be very air tight.  Additionally, in order to receive a rebate for the installation of  a geothermal heating system, we had to install a bead of silicone  wherever  any two lumber framing  butted up against each other.

Open Cell Spray Insulation:

In order to pass the blower door test, we decided to use an open cell insulation called Icynene.  The product has performed beautifully.  However here are my regrets:

• Icynene contains a petroleum based material.  Although the product reduces energy consumption, natural resources are used in order to make the product.   Some question whether open or closed cell insulation is green citing  that  spray foam off gases.  Honestly, I wasn’t able to discern from the article whether the author was discussing closed or open celled or both.
• There is air infiltration where the wall meets the ceiling and the floor because foam is sprayed in between the framing bays not on the wood itself.  In retrospect, I would have either used SIPS (structural insulated panels) or rigid insulation to add insulation over the framing members.   Wood has a low R-value.

9 Other  Green Insulations:

Spray foam isn’t the only insulation option.  Listed below are other green insulation alternatives.

1.  Wool insulation:  Oregon Shepard offers wool insulation sourced from the US. There are not any flame retardant added to the product since wool is inherently flame retardant.   See the prices here.  (Be sure to watch my video interview here about the product.)

2.  Bonded Logic’s Blue Jean Insulation:  This insulation is install in my interior  walls for soundproofing.  If I had used it in my exterior walls, then I would need to  install a plastic vapor barrier over the insulation.

Bonded Logic is made of industrial pre-consumer jean waste.  Some argue that this product isn’t sustainable as well since it comes from cotton fields that require pesticides and extensive watering.

3.  AirKrete Cement Insulation:  I love the concept of this product.  AirKrete is an open cell cement based foam which is  inherently flame retardant since it is made of Magnesium Oxide.  Note, it is not made of energy intensive Portland cement.  Be sure to listen to my podcast with an AirKrete installer.  One of the advantages of this  insulation is that you can blow it into the walls of existing construction.

4.  Closed Cell Foam Insulation:  As I mentioned above, there is much debate as to how sustainable foam insulation is.  Closed cell offers an airtight solution and has one of the highest R value per inch.  We chose not to install closed cell since we were “warned” that the product off-gassed.

In addition,  closed cell is not water permeable.  If you have a leak where closed cell is installed, it may be hard to find the source of the leak since water cannot penetrate close cell.  As we all know, water finds its way and may start leaking from a completely different location than the original source.

Read here for my article on closed cell insulation.

5.   Mushroom insulation:  Years ago, I wrote about Ecovative’s  mushroom based packaging.  The Company now offers both myco foam insulating sheathing (rigid insulation)  and experimenting with a controlled environment grow in place mushroom insulation which is an alternative to spray foam insulation.  This application is for pre-fab structures.  Be sure to check out their mushroom tiny house.

6.  Hempcrete:  Hempcrete is a blown in hemp insulation.  It is naturally fire, rot and termite retardant. In addition, the walls are breathable (vapor  permeable.)

The downside is your wall cavities must be deeper than the average 2 by 6 construction.  For example, in order to achieve an R-value of 25, the wall cavity must be at least 12 inches deep.  Be sure to watch the video about  the Ashville, North Carolina home in which hempcrete was used.

7.  Cellulose:  In my prior house we insulated areas where there was air infiltration with cellulose, which is comprised of recycled newspaper (up to 85% recycled material.)  Some of the areas seemed like they settled or there wasn’t sufficient cellulose in those areas.  Both Home Depot and Lowes carries a DIY GreenFiber Blown in Cellulose Insulation.  (It is formaldehyde free.)

Cellulose does contain aluminium sulfate or borate based flame retardants .  Use products with borate based retardants since sulfate retardant cellulose can form sulfuric acid when the cellulose comes in contact with moisture.   This acid can cause damage to metal such as plumbing and wiring.

For more information about cellulose insulation, read here.

8.  Bio-based insulation:  Biobased insulation is similar in application to the spray foam insulation except a percentage of the foam is made of soy.  Rhino insulation offers both open and closed cell insulation.  Open cell BioBased 501w has 3% bio-based content and  closed cell DuraTite 2.0 has 3% bio-based content as well as 3% pre-consumer recycled content in the finished foam.  DuraTite is Greenguard certified for indoor air quality.

9.  Straw Bales:  Straw is used as either as  insulation or as part of the structural component of the building.

“Two basic styles of straw bale construction have been used: post and beam construction with straw bale infill, and structural straw bale construction or “Nebraska” style (the weight of the roof is supported by the bales).” {Source}

The material is baled straw from wheat, oats, barley, rye, rice and other grains.  The walls are covered with earthen or lime stucco.

For more information about straw bale insulation, watch this video on 7 reasons why you should consider building a strawbale  house.    Strawbale.com contains an extenive FAQ about working with straw.

 Join the Conversation:

• What type of insulation do you have in your home?
• Have you used any of the above products?  If so, what was your opinion of their installation and performance?

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• Recycled Denim Insulation by Bonded Logic: Green, Warm, and Itch-Free
• Wool Insulation by Oregon Shepard: Natural, Energy Efficient, NonToxic