A few months back I ordered and received a “Digital Utility AC Power Consumption Monitor and Timer” from DealExtreme (see my initial post here). I’ve now used it to briefly measure the power consumption of my home tumble dryer in “Warm” mode.
A common use pattern is to put a moderate load of washing into the dryer’s “Warm” mode for ~90min, and then do it again if the clothes aren’t dry after once cycle. (In theory this avoids overheating the clothing by simply doing a single “Hot” cycle for 60-90min. But I digress….)
Early in a “Warm” cycle the power draw is around 1840-1850W. The motor is working reasonably hard to tumble wet clothes and the heating element is creating warm air.
Around 50min later, the timer dial was sitting under the “30min left” mark, but still above the “Cool” zone. The heating element is now off (room temperature air being cycled through the unit) and the power draw had dropped significantly to 146-148W.
After this first cycle, total energy draw was reported as 1.23kWh. However, the clothes were still all damp, so we started another 90min warm cycle. After the 2nd cycle, total consumption had risen to 2.50kWh and the clothes were all dry.
Although 2.50kWh is a substantial fraction of our daily average (~20kWh according to recent electricity bills), lets put this into perspective. Currently I’m being charged ~20 cents/kWh, so doing two runs of the tumble dryer cost ~50 cents (ignoring the fixed daily costs of merely having mains electrical power delivered to the house).
50 cents for two runs of the tumble dryer is line noise compared to the financial impact of small decisions taken every week for groceries, lunch or snacks at work, etc (this meat, or that? toppings for the sandwich, or not?)