Alex's data over the past two weeks

Alex has collected data from his house over the past 2 weeks, recording both instantaneous power readings and energy consumption over each period. The following feeds have been metered:

• Household aggregate
• Tumble dryer
• Washing machine
• Dishwasher
• Fridge
• Computer
• TV

The pie chart below shows each metered appliance's share of the total energy consumption.

This is similar to what we'd expected, as the metered appliances account for roughly half of the total energy consumed (if we pretend the 'always on' appliances are metered too). The most surprising thing is that the tumble dryer doesn't appear to have consumed any energy. This is most likely due to Alex simply not using the appliance, but it could also be due to the appliance being unplugged from the Plogg.

I've also run my script to subtract each metered appliance's energy consumption from the aggregate reading for the same period. The graphs below plot the energy consumption of Alex's house over one day, excluding the appliances listed above.

Day 1:
Day 2:
Day 3:

The most interesting point of these graphs is how few of the appliances appear to overlap. This is in stark contrast to plots of the household consumption without any appliances removed. This supports our assumption that subtracting known signatures from the aggregate can be useful in identifying unknown signatures.

Another interesting feature is the varying energy consumption overnight. Now that the fridge has been removed, I would have expected this to be constant. However, there are two possibilities that could account for this variation. The first of which is noise. This would be introduced if the periods over which each meter samples differ. Alternatively, the variation could also have been caused by appliances with uneven energy consumption that we simply haven't considered yet.