Rob Ewaschuk's Blog : /life/metrics Rob Ewaschuk

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/life/metrics/Is Your Refrigerator Running?

Why yes, it is!

Not only that, but Between January 18th at 12:10 and the 31st at 13:00, it used 32.39kWh, or about a buck fifty of electricity. That's an average about 103 watts. Unfortunately this period was biased by a brief period (12 hours? We're not sure) where the volume of groceries in the freezer exceeded its capacity and it ran non-stop.

When running, it consumes about 236 watts. Assuming this value is fairly steady (it's an old fridge, so I imagine it occupies only two states in the on-off spectrum), it's on about 44% of the time.

Our last electricity bill was 1183kWh over 66 days, an average of 747 watts, so the fridge uses about 14% of our power. Except that measurement problem listed above, but I think that should be relatively small.

Another way of looking at this is that it's about 900kWh per year, or 75kWh per month; the sticker inside says 110kWh per month, so it's actually over-performing, which is surprising. Perhaps it's rated against a higher indoor temperature than we keep.

A quick perusal of Future Shop's refrigerator selection shows that modern fridges seem to be rated between 400 and 480 kWh/year. That's 40kWh/month at the most. So, assuming those numbers are accurate, we'd save 35kWh/mo, or about two bucks. At that blistering pace, the fridge would pay off in about 16 years.

I'll have to take the same measurement in the summer, when things are a little less refrigerator-friendly round here.