Eco-friendly Insulation: Sheep’s Wool

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Sheep’s wool is an environmentally friendly insulation. Here are some pros and cons of using it in the modern home.


Almost anywhere you live, you need insulation in your home. It keeps heat inside during cold winter months, and outside in summer. Insulation in walls, ceilings, and floors will reduce your energy bills and save natural resources.

By choosing sustainable insulation, you are doubling that value by saving even more precious resources. Sheep’s wool is one example of natural insulation to be used in homes.

Eco-friendly sheep’s wool: production

To me, sheep’s wool is the quintessential natural insulation. Sheep can live in cold, harsh climates due to the wool that covers them. Why shouldn’t that translate to a home? Sheep are shorn annually, and the B grade waste material from the wool industry is processed for other uses, including insulation. Already, wool insulation is keeping waste from landfills.

Processing wool uses a fraction of the energy it takes to make fiberglass. That’s another point on the eco side. It comes as batts and loose fill with an R-value between 3-4 per inch of thickness. You can install it yourself, and you won’t need a respirator or long sleeves!

sheep shearing

Naturally breathable insulation

Wool is breathable. It absorbs and releases moisture without losing its insulating properties. Wool is the perfect material for outdoor gear for this very reason. When you get wet, you stay warm. When fiberglass, the traditional insulation material, gets wet, it compacts, settles, and stops insulating.

Wool is water resistant, flame retardant, and non-combustible, meaning if it catches fire, it will not burn. It keeps its shape, so it never settles down into the wall or compacts in the ceiling. It has excellent acoustic properties. Wool is natural, can be recycled, and is biodegradable. Being non-toxic, it does not have a negative effect on indoor air quality. It also absorbs air pollutants and breaks them down, further improving indoor air quality.

sheared sheeps wool

(image: Ken Hammond)

Negative attributes

Wool is not perfect, but nothing is. The big picture is as important as the small details. If you look at the supply chain of wool insulation, you might want to consider that sheep are dipped in pesticides and fungicides to prevent bugs and diseases. There may be some residue of those pesticides on the wool.

Sheared wool is treated with Borax and other chemicals to prevent moth infestations. I was not able to find cost-effective, natural treatments as an alternative.

You may not be able to find wool insulation locally. It is readily available in the UK and Australia, but it has not hit the US market in a big way yet. So that brings us to CO2 emissions of the transportation. There’s a good chance your wool insulation will be well-traveled from the time it leaves the ranch to when it gets installed in your home.

[ED: Also, some sheep really hate getting a “haircut”.]

Personal choices

As with choosing anything with a small environmental impact, there are trade-offs. Maybe for you, the durability and breathability of this natural fiber will offset the miles it traveled. Maybe not. Any time we try to lower our carbon footprint, these are personal choices we have to make.

Do the pros outweigh the cons when it comes to sheep’s wool insulation for you? Tell us your take in the comments section.

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Nan Fischer

Nan Fischer has been living and building green for over 35 years. Nan’s emphasis on the BuildDirect blog is about how to make your dollar stretch further, while also moving toward a more sustainable lifestyle, as well as upcoming and existing technology to help us live in an ecologically-friendly way. Nan also authors posts on the website of her seed business, sweetly seeds.