Wow, thanks to reader Adam for pointing out that there does indeed exist stateside manufacturers of wool insulation batting. (This GreenHomeBuilding.com Q&A is outdated.) Good Shepherd Wool Insulation, based out of Interlaken, NY, manufactures 16″ and 24″wide wool batting rolls for conventional construction and timber frames, and rope wool for log home building.
Wool is one of the best natural insulators — it’s a natural product (duh), it repels pests, is non-allergenic, can absorb indoor air pollutants, and has excellent insulation and moisture retention capabilities:
Research funded by the Wool Research Development Corporation has shown that wool is a better thermal insulator than other fibers under typical weather conditions because of its ability to absorb and desorb moisture from the air. It can help keep a building cool in summer and warm in winter.
When outside temperatures increase the wool is heated and releases moisture which has a cooling affect on the fiber and the building. This may reduce temperatures by up to 7E °C.
When outside temperatures decrease the wool absorbs moisture which can increase peak temperatures by as much as 4E °C.
Pretty fantastic. I am still exploring whether or not their batting is a possibility for the floor and roof of Strawtron, but time will tell…
I know that non-organic wool fabric contains insecticide. Does this wool have a treatment to deal with pests like moths?
I’ve lived in places with mice and they would love to make their home in between joist filled with insulating like straw or wool. It’s like your doing most of the work for them. If the flooring on top of that allows crumbs to fall through all the better for them. Do you have any plans to make your kitchen less mouse friendly?
Is there going to be attic space? I know it’s not as beautiful as an open ceiling but an attic space with straw bales is going to be the most environmentally viable thing to do long term. unless you are planning on putting in a ton of wool there is no way it’s going to come close to the R value of straw bales.
hi, based on our experiences here you should take damn good care that the wool is treated against moths – they love the protein of wool and will build big families inside your insolation within some years. untreated wool works well for a couple of years (3-5), but afterwards there is a massive moth problem. (except those homes, which got freezing cold once a year, below minus 10 degrees celcius for a couple of days – that keeps number of surving moths low).
there is an organic way to treat the wool against moth; the stuff is called borax in germany (should be sodium borate), some natural salt, which needs to be dispersed in hot water and the wool needs to be soaked into and dryed well afterwards.
have fun with planing!
simon // germany
We’ve used Good Shepherd wool insulation in part of our house. It is treated with boron to prevent moth infestations. As far as I’m concerned it is the gold standard for insulation, but it is very expensive.