Home Energy has been covering the energy, economic, even sociological aspects of refrigerators for many years. Here are a few leftovers from our refrigerator shelves.

Slamming the door on a myth. Shopping carefully for an efficient refrigerator will help more to save energy than policing family members to minimize door openings (Refrigerator Folklore, Nov/Dec '90, p.8). This is the conclusion of researchers at Purdue University who found that the difference between opening the door 80 times a day and leaving it closed was modest in terms of overall electricity use--about 25%. Even if the refrigerator police cut door openings by 20 per day, a diligent family would realize energy savings of only about 6%. The unpleasant conclusion is that, once purchased, a refrigerator's energy consumption cannot be reduced significantly by modifying behavior.

Try fudge with labels. Just as EPA's car labels add a big dose of uncertainty with a disclaimer--Your mileage may vary--so Energy Guide labels have drawbacks (Your Mileage May Vary, Nov/Dec '88, p. 12). The standardized tests by refrigerator manufacturers do not duplicate actual use. Hence, energy use for an individual refrigerator may differ from the label value by as much as 40%. In addition, refrigerator energy consumption varies seasonally. Energy planners and auditors should avoid using uncorrected label information to make energy consumption estimates, and if short-term metering is a must--less than one year--they should add a fudge factor of 20-30%. (See Yellow Labels, p. 29, for a current analysis of labels versus actual energy use.)

Smart refrigerators. Using energy-efficiency as a selling point can help the consumer with lower energy bills--or it can be a conduit to higher ticket prices without measurable paybacks in energy savings. Some new models have featured indicator lights to remind owners to clean dirty exterior condenser coils, allegedly a cause of reduced efficiency (Dirty Coils and Indicator Lights, July/Aug '91, p. 8). However, these lights are not activated by actual dust build-up on the coils, but according to a pre-programmed time interval, often 90 days, raising many questions about the usefulness of this feature. On the other hand, an adaptive defrost command operates according to real performance measurements. Depending how long a defrost cycle lasts, the refrigerator shortens or lengthens the time between defrostings, for example when the door is kept closed. Sometimes modern refrigerator conveniences mean more energy consumption, but the effect of this feature can reduce it. A wrinkle on the variable timed defrost control is the vacation mode switch which slows the defrost cycle frequency.

Airing The Coils. Almost universally, kitchen designers provide a space for the refrigerator that could best be described as a cocoon. Cabinetry and counters block ambient air circulation to the coils. Efficiency falls as temperatures behind the refrigerator rise. A Berkeley engineer metered his refrigerator for two months. Then he cut slots into the overhead cabinets, creating a plenum through which passed air heated by the coils, pulling cool air over the coils from below. This 30-minute surgery cut energy use 15% (Suffocating Refrigerators, Mar/Apr '91, p. 7). -- Jim Obst

Figure 1. Modified cabinet permits convective air current under and behind refrigerator. From Suffocating Refrigerators.