How green is your insulation?

It’s important to save energy by insulating your home, but not all insulation was created equally green - some use harmful toxins as preservatives and some require polluting manufacturing. So what are the best options for staying warm without contributing to global warming?

Fiberglass Products (R Value – 3.1 – 4.3 per square inch)

There are dozens of insulation products on the market but the most common are fiberglass, especially batts and blankets. These are made from molten glass and generally contain some recycled material. They work reasonably well as insulators although, if not cut properly to size, can allow cold air in through gaps.

Not all fiberglass Batts are created equal – many come with an asphalt facing which further contributes to carbon emissions in the manufacturing process but most controversially, fiberglass insulation often contains formaldehyde.

Formaldehyde is a well known carcinogen and most states have now banned other formaldehyde products, including urea-formaldehyde foam as they were found to compromise air quality in the building. The International Agency for Research on Cancer also lists fiberglass itself as a “probably carcinogen”.

Wool Products (R Value -3.5 -3.8 per square inch)

Wool is considerably more expensive than its man made counterparts which has limited its popularity. Wool insulation manufacturing is relatively simple compared to its competitors and emits relatively low levels of carbon, even when considering the upkeep of the sheep. A non-toxic clay substance is usually added in the production process but it is considered harmless. There is some controversy over the effectiveness of wool insulation; however a report by the Australian science institute CSIRO found, when installed optimally, wool had greater insulation potential than its counterparts.

Cotton Batts (R Value – 3.7 per square inch)

Cotton Batts are usually made almost exclusively of recycled materials and contain no formaldehyde and very few petrochemicals. Although cotton is a particularly destructive, water intensive crop, the damage it does is not comparable to an oil well or mineral mine. A small quantity of polyolefin, a petroleum based adhesive is used in production but is preferable to formaldehyde.


Cellulose Insulation (R Value – 3.4 – 3.8 per square inch)

Loose Fill Cellulose insulation is generally used for tricky to reach areas such as wall cavities as well as ceilings. It’s quite heavy (therefore positing a risk of structural damage) and tends to become less effective over time however, it is perhaps the best option if you are looking to go green. It contains no petrochemicals so it does not require excessive oil refinery in production and has no known carcinogens. Cellulose insulation is made mostly of recycled newspaper so it plays a part in reducing landfill in addition to saving energy.

Of course there are dozens of other options from paints that insulate to bales of straw under the floor boards – finding the right option for your home depends on your location, dwelling and priorities.


Dana Flannery is a freelance writer on all things good for families and the environment. See more of her work at this Outdoor Wedding Planner site and at this Brisbane Marriage Celebrant site.