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Friday, October 31, 2014

Green Insulation

Source: Flickrr
Image: U.S. Dept. of Agriculture

Insulation, by it's very energy-conserving nature, was already considered by some to be green. However today we can choose to go much greener thanks to a wide array of choices and advances in insulation technology. An insulation's R-value measures its resistance to heat flow ranging from R-1 to R-60. The higher the R-value, the more it restricts heat flow, but also the more expensive it can be. Your goal is an R-value in your home between R-30 and R-60. So if an insulation has an R-value of 3 or 4 per inch, you'll need ten inches of it to achieve your goal.

Yes, those are soybeans pictured above. Move over fiberglass insulation, now there's something healthier. Of course the insulation doesn't look anything like this handful of beans. Instead, it's a convenient, white spray foam available through companies like www.thegreencocoon.com. With an R-value of R-5.5 it's quite efficient and also provides a good sound barrier.

Denim or cotton insulation
Source: Flickrr
Image: Nicole Hennig

Insulation keeps heat in during cold weather and the cold air in during hot months. How much energy costs can be reduced has long been the deciding factor in selecting insulation, but now consumers are also rightfully concerned with chemicals and their carbon footprint.  HVAC systems are also responsible for approximately 44% of the energy used in a home. Denim or cotton is a natural and renewable resource, making it one of the greenest insulation products on earth. While cotton insulation costs twice as much as fiberglass, it doesn't contain formaldehyde which some studies have linked to certain types of cancer. It's also very effective when it comes to absorbing moisture. When treated with boric acid, it's flame retardant. It's also insect repellant. It rates R-3.2 to R-3.7.


Sheep's wool insulation
Source: Flickrr
Image: Laura Stephens

Pictured above, these tiny house builders have opted for sheep's wool insulation, joking, "It's going to be like wearing a huge, shed-shaped jumper." They're probably not far off considering sheep thrive in some of the harshest climates, including the Arctic. Sheep's wool insulation has the added benefit of producing heat whenever it absorbs moisture, which prevents condensation. You don't need to adjust your heating and cooling system as often with Sheep's wool either. It has an R-3 to R-4 rating.


Polystyrene
Source: Flickrr
Image: pshab

Most would never guess polystyrene is a green material, but it is an excellent insulator. Normally it's in the form of rigid, foam boards. These are actually sound waves reflected in polystyrene from an exhibit at the Explore Science Centre in Bristol, UK. Polystyrene will not only efficiently insulate your building, but it will add structural integrity to its walls. It also comes in spray foam. Even though it's plastic and takes some time to break down, it can be recycled. This has an R-value of R-3.8 to R-4.4.

Aerogel is an incredible insulator formed by removing the liquid from silica utilizing high pressure and temperatures. The molecular structure isn't conducive to heat passing through aerogel. It comes in easy to use sheets and adhesive strips, but it's very expensive at up to $2 per foot. R-value? R10.3!

Icynene is a spray foam insulation that seals and insulates your home like no other. It expands to nearly 100 times its volume once it hits the surface of the area you're spraying. It's great for sound-proofing too. Water vapor is allowed to escape, preventing mold from taking root. However, it's about three times as expensive as fiberglass insulation and requires a ventilation system due to its super-tight, blanket-like seal. In colder climates an air exchanger is also necessary to warm incoming air. The R-value is R-3.6.

Last but not least, let's not forget earth, as in the soil surrounding the earth homes we discussed in our last post at an R-value of R-.25 to R-1.0 it doesn't sound so impressive compared to the others we've covered, but you need to take into account moisture factors. Wet soil has a much lower R-value than dry soil. Both are great sound barriers, though. The type of soil will naturally make a difference in the R-value as well.