I bought a roll of Pellon wool batting because it was on sale and I wanted to try wool. I agree with what others said-- it's lighter weight than cotton, and it's warmer than cotton. The first time I washed the first quilt I made, the wool 'bearded out' through the 100% cotton pieced front, and the 100% cotton backing. It did not come out through the needle holes from the quilting, or the seams from the piecing, but rather just everywhere. Every time I wash and dry it, it has pills of wool on it. It gets thinner and thinner every time. I made another quilt, and wondered if pre-washing the fabric would help to keep the wool batting inside, but the same thing happened. I gave away the rest of the roll of batting in disgust. It might make a warm pet bed made with corduroy or fleece on the outside? If I use wool again, it won't be the Pellon brand.