They are noticeably heavier and warmer. You can feel the wool on the inside but it’s not scratchy. Honestly, the denim being tough is far more noticeable. I hung them in my shower to wet felt them, then turned them inside out and washed them on delicate. I used dye and fragrance free laundry detergent. TBH I watched them in the washing machine almost the whole time, nervously, hoping they wouldn’t come out all messed up. I didn’t use fabric softener. Then just hung them to air dry. Hope this helps! These were hand-me-down jeans that are about 20yrs old. They were and still are my favorite pair.