Denim quilts are heavy, and very warm! I love them! Most laundromats are not on septic and cotton is biodegradable anyway. At our old house I had problems. The plumber said cotton is biodegradable and not a problem (unlike hair). Our problem was the pipes were small and caving in because it was very old. If your septic system is in good shape and you are not worried about your washing machine then go for it at home. If you want to go to a laundromat, they have larger drain pipes to accommodate all the washers at once whether they are city or septic. I don't think all the thread gets out of them when you put them into something else. It seems to take more washings.