Why is there a need to do a carpet dry cleaning when steam cleaning machines are readily available for use? The answer is simple. Steam cleaning uses hot water and detergent to clean the carpet and will take time to dry. This means, you will have to wait about 12 to 24 hours to let your carpet sit and be able to use again. With dry carpet cleaning, it uses chemical agents which is more effective in cleaning carpets and no time needed for drying.