Distribution of electricity consumption august 2010

Besides for monitoring our solar panels, I have also connected a number of of the Plugwise measuring devices to a number of electricity consumers.

Plugwise () claims on their website that their system should enable large savings on your electricity bill. That won’t fly in our situation because I think we’ve done nearly everything possible to reduce our electricity consumption, but it might very well be true for households that are at the beginning of their energy savings journey.

The plugs allow me to gain insight into the distribution of our electricity consumption. I’ve estimated this distribution () before, but now I can actually (although only partially) measure it. Unfortunately I used a different classification system from the Plugwise plugs, so it’s not completely comparable, but some parts match quite well.

I estimated that our computers used 11% of the total electricity consumption, which turns out to be 9,4% after measuring. When considering the inaccuracies in both the estimate and the Plugwise measuring system that’s not bad at all. The same goes for the refrigerator: I estimated it would use 29% of the total which turns out to be 27,2%. The other categories are defined differently enough to make comparison difficult. I estimated ‘clothing care’ (washing machine and iron) as using up 15%. According to the measurements our washing machine used 10,4%. I estimated we did four to five washes per week which turned out to be quite accurate as we ran the machine 18 times in August 2010. We don’t iron much, so I don’t think the iron (the only other appliance in the ‘clothing care’) used up 5%. I don’t know where the difference comes from but as the actual consumption is less than I thought I’m not going to try to find out.

We have a portable electric heater which – fortunately and unfortunately – came in handy when our roof had leaked badly during the heavy rains in the end of August. I wanted to dry all the woodwork in the loft thoroughly so the heater ran a few hours for two evenings, which used 6,7% of the total. As we have a substantial yearly surplus I don’t worry about that.

Verbruik van de koelkast en CV-ketel in 2010

When looking at the distribution through the year until now two appliances show clear trends: the refrigerator and the central heating system.

In the winter months the central heating system clearly runs for far longer periods to heat our home, and this lowers significantly in the spring.

The refrigerator shows an opposite trend: in the winter the average living room temperature is low (the temperature lowers at night and when we’re not home) and under those circumstances the refrigerator doesn’t have to work as hard to maintain it’s temperature. As the outside temperature rises in the spring the average living room temperature also rises and that increases the refrigerator’s power consumption.

As a bit of a ‘measuring nut’ I love connections like these. A bit of common sense predicts these connections are present but I truly love making them visible in graphs.