Built-in Appliances: Combining Thoughtful Design Innovation with Superior Energy Performance

Architects can specify built-in appliances with world-class design features that use less energy by incorporating the latest appropriate technology.
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Sponsored by Electrolux Home Products, INC.
Peter J. Arsenault, FAIA, NCARB, LEED-AP

Refrigeration Appliances

Refrigerators and freezers are often the largest single energy-using appliance in a typical household and, consequently, are the single appliance most responsible for carbon-dioxide emissions. A typical energy bill can reflect almost as much energy use for a refrigerator (6 percent) as lighting the entire house (7 percent)-easy to understand when we realize that refrigerators necessarily need to be "on" 24 hours a day. A new, more efficient refrigerator can typically save $70 to $80 per year, and will pay for itself in about nine years. Specifying a model that qualifies for the EPA's ENERGY STAR label will be at least 15 percent more efficient than the federal minimum standard for all other refrigerators.

Built-in refrigeration can enhance the overall design and functionality of kitchens and other spaces.

Photo courtesy of Electrolux ICON®

 

When specifying energy-efficient refrigerators, consider the following recommendations:

- Specify an ENERGY STAR rated or better, refrigerator or freezer. Note that there are some models that just meet the minimum requirements, and some that far exceed them. Therefore, it is possible to specify more than just minimum (i.e., 15 percent above federal standards) requirements and accept only models that exceed requirements (i.e., 20 percent or greater than federal standards).

  • Combination refrigerator/freezer appliances with either a freezer on top or, even better, in a bottom drawer, are generally more efficient than side-by-side swinging-door models, although specific data should be looked at for particular models for proper comparison.
  • Manual defrost models use half the energy of automatic defrost models, but must be defrosted periodically to remain energy-efficient.
  • Automatic icemakers and through-the-door dispensers will increase energy use by 14 to 20 percent.
  • The most energy-efficient models are typically the 16 to 20 cubic foot sizes.
  • Locate the refrigerator in a cool place away from a heat source such as an oven, a dishwasher, or direct sunlight from a window. Further, be sure to design in space that allows air circulation behind the unit.

Often the question arises regarding the number and size of refrigeration units to include in a kitchen or other locations. Generally, it is usually less costly to run one larger refrigerator rather than two smaller ones. However, for design situations that call for multiple or separated locations, each unit should be sized for optimal performance by choosing sizes and types that are best suited to the intended use and capacity. General-use refrigerators should be kept between 35 to 38 degrees Fahrenheit for best efficiency. Wine coolers which have become more popular, particularly in under-counter styles, are often kept in the 50 to 60 degree range, requiring less energy to achieve this level of cooling. Separate, smaller, under-counter ice makers may also be logical in situations where they are needed only occasionally and can be turned off in between use. This leaves room and greater efficiency in the main refrigerator or freezer for other uses.

Water-Using Appliances

In addition to energy, the importance of water conservation in appliances should not be overlooked since many recent standards with an emphasis on energy also include requirements to reduce water use. This is because it often requires a lot of energy to treat, process, and move water, not to mention the strain on the quality and quantity of local water sources. The Associated Press has reported that by 2030, the implementation of the water-saving provisions of recent environmental legislation will reduce water consumption by 10.5 trillion gallons, with a corresponding $15.3 billion saved in electricity costs. According to other news sources, "In some regions, like the western U.S., where fresh water can be scarce, household consumption has a significant impact on the watershed, which affects salmon runs and the poorer developed areas when water is diverted to supply new communities, resort areas and agriculture." Responsible use of water is a serious and growing issue that can be addressed not only in plumbing fixtures but also in electrical appliances that require water to operate, such as clothes washers and dishwashers.

Dishwashers

Built-in dishwashers with appropriate controls save both energy and water.

Photo courtesy of Electrolux ICON®

Overall energy use and hot water use are the drivers in dishwasher performance. A significant portion of the energy used by dishwashers is actually the energy required for heating the water they consume, since almost all dishwashers on the market use internal booster heaters. That is actually a good thing, because it allows domestic hot water heater temperatures to be turned down to around 120 degrees, instead of the higher temperatures usually desired for dish washing. The lower water heater temperatures mean less energy is used on an ongoing basis with the higher temperature created only for the intermittent needs of the dishwasher. Specifying a dishwasher that addresses the following will help boost performance:

  • ENERGY STAR rating. First and foremost, specify a model that meets or exceeds the ENERGY STAR rating requirement for both energy and water usage.
  • Water usage. Specify a unit that requires less water overall and more options on controlling the water used. Many newer models have been documented to actually use half the water that conventional hand-washing would require. Further, rinsing dishes can use up to 20 gallons of water before the dishes are even loaded. ENERGY STAR qualified dishwashers used with appropriate detergents are designed to do the cleaning instead of hands.
  • Rinse option. For times when dirty dishes sit overnight, a dishwasher with a rinse feature will typically use a fraction of the water needed to hand rinse.
  • Load size. Dishwashers use about the same amount of energy and water regardless of the number of dishes inside, so sizing the unit to promote running full loads whenever possible will be appropriate.
  • Drying. Specify units that have a no-heat drying option. This typically gives good drying results with less energy.

An additional significant specification detail is to call for a dishwasher that incorporates soil-sensors, since they adjust water use depending on how dirty the dishes are in each load. Recent improvements in test procedures better estimate the energy consumption of soil-sensing dishwasher models, allowing more accurate comparisons between models.

 

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Originally published in Architectural Record
Originally published in June 2011

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