Front-Load Laundry FAQs:

Front-Loading vs Top-Loading HE Washers

This new generation of high efficiency washers uses a different washing system than its traditional parent appliance - a gentle rotating tumbling action rather than a harsher agitation to get clothes clean. A high-efficiency top-loader has a slightly different washing action, a re-designed shorter agitator that draws the load down into the low water and detergent to effect a cleaning. HE top-loaders must meet the same stringent guidelines in order to be called HE washers and either style is efficient when it comes to cleaning performance.

HE Detergent Use

Because a high efficiency washer uses less water, low-sudsing HE detergent must be used in these washers in order for cycles including the rinsing action to work as designed. This applies regardless if the washer is top-loading or front-loading, as long as it has the HE seal.

Other Benefits of a High-Efficiency Laundry Team

High-speed spin cycles remove more water from the load, resulting in shorter drying times. Load capacities are generally larger than with a traditional washer, partially because the agitator is gone (or much shorter), which means a few less washloads to process - less water, detergent and energy to wash and dry.

Accompanying dryers must also meet certain criteria for lower energy use to carry the HE symbol. The Energy Star program has not been extended to dryers. Lower washer water levels means there's less water to heat which means less energy use.
(Quoted from About.com)