If you have a top load washing machine at home and a typical front load washer in the RV, they may not use the same laundry soap. High-efficiency detergent is specially formulated for use in all front-load washers and some high-efficiency top loaders as well. 'HE' detergent is concentrated and produces fewer suds than regular detergent. This is not RV specific of course, since it applies to all front load washers.