With energy-consuming equipment, such as water heaters and refrigerators, we have good data on energy consumption and can set clear standards accordingly. In some product categories—clothes washers, for example—Energy Star standards were adopted because those standards provide a high enough threshold to represent just the very top segment of the product market (less than 10%). In other product categories—e.g., refrigerators and dishwashers—we set a higher threshold than ENERGY STAR: for example, exceeding those standards by 10% or 20%. With lighting and lighting control equipment, certain generic products qualify, such as compact fluorescent lamps and occupancy/daylighting controls, while in other categories only a subset of products qualify. In some cases, products that meet the energy efficiency requirements are excluded, because of evidence of poor performance or durability. Microturbines are included here because of the potential for cogeneration (combined heat and power) that they offer.
All toilets and most showerheads today meet the federal water-efficiency standards, but not all of these products perform satisfactorily. With toilets and showerheads, we include products that meet or exceed WaterSense standards, which includes performance requirements—although we go beyond WaterSense where there are issues not adequately addressed by the program. We also look for other products that conserve potable water, such as rainwater catchment and graywater recovery and reuse systems.
LG offers residential dishwashers with energy factors of up to 0.90, using as little as 2.50 gallons per cycle and 245 kWh of electricity per year, exceeding the federal standard by 31%. These units measure water turbidity to adjust water demand and shorten cycle lengths and provide quiet operation at 45 dB. Dishes are dried by a condensing system that uses a fan to draw warm, moist air into a condensing duct and uses heat retained by the dishes and the stainless steel tub to save energy. Some models come in stainless steel only, while others offer a choice of black, white, or stainless steel.
Most of the energy consumed by dishwashers is used to heat the water; therefore, water-efficient dishwashers are also energy-efficient. Compared with hand washing dishes, the EPA estimates that using an Energy Star-qualified dishwasher will save 5,000 gallons of water annually. Scraping dishes rather than rinsing by hand saves an additional 20 gallons of water per load.
As with other home appliances, national energy standards have catalyzed the development of more efficient dishwashers. As a measure of efficiency used by the EPA’s Energy Star program and the Consortium for Energy Efficiency (CEE), the Energy Factor (EF) describes energy performance under carefully defined conditions, and provides a basis of comparison among different models. The equation for EF is estimated loads per year divided by the annual energy usage (kWh/year). The national energy standard requires all regular size dishwashers to have an EF of at least 0.46.
Products listed in GreenSpec meet CEE Tier 1 standards with an EF of 0.75 or greater, a maximum annual electricity usage of 295 kWh, and a maximum water usage of 4.25 gallons per cycle. There is some evidence that the integral water heater in some dishwashers may not be adequately accounted for in the standardized test procedures, so actual energy use may be higher than predicted.
EAc1: Optimize Energy Performance
EAc1.4: Optimize Energy Performance—Equipment and Appliances
EAp2: Minimum Energy Performance
EAp2: Minimum Energy Efficiency Performance
MRc2: Sustainable Purchasing—Durable Goods
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