The Coxson household claims to have a highly efficient Sun Frost RF-12, but the numbers reported in your article can't be correct (see "One Family's Savings," May/June '92, p. 10). It should consume about 170 kWh per year, not 350 kWh per year as reported. Perhaps their consumption didn't drop more because the vintage 1950s refrigerator, which may have been previously in use in the Coxson household, consumed relatively little energy. Low energy use of those old models was a result of their small size, thicker walls, slower turning, more efficient compressors, and manual defrost.

By the way, one of our customers, Kevin Stam, runs his 16 ft³ Sun Frost RF-16 on the equivalent of the 160 W using energy from solar panels. He utilizes previously owned panels, each putting out 53 W and measuring about 14 in. 2 48 in., with a total output of about 160 W. His refrigerator consumes about 220 kWh per year.

Larry Schlussler
Sun Frost
Arcata, CA

Editor's Note: Without a disaggregation of the energy users in their home, the Coxsons weren't sure of the actual energy consumption of the Sunfrost by itself. Now they are. Pam Coxson told Home Energy that metering has revealed their super-efficient refrigerator uses .5 kWh per day, or about 182 kWh per year, not far from Schlussler's claim. Since these measurements were made during a week when the daytime temperautres in the kitchen exceeded 80deg.F, she thinks this may have influenced the readings. According to Sun Frost, says Coxson, on 70deg.F days the RF-12 should use .35 kWh per day, and on 90deg.F days it should use .56 kWh per day. Stay tuned for more readings with the Sun Frost relocated to a cooler part of the house, she promises.