The cooler uses roughly 0.58 kWh of electricity per night (see “Thoughts inspired by the release of our other co-latest Green Guide: Greening Your Office”). So our gross savings using the automatic on/off timer are 0.58 kWh per day. Meanwhile, the timer uses roughly 0.024 kWh per day. That gives us a net savings each day of roughly 0.556 kWh. The financial payback time for the timer is probably something like 4 months. After that, it’s all savings, all the time.Of course, Jonathan tells me, the financial payback time depends on how much energy the timer is saving you—the bigger the energy hog, the faster the payback time.