The Power of Energy Efficiency revisited

15 12 2011

My “Power of energy efficiency” post has created a lot of traffic on this blog, and while visiting our electricity supplier’s website, I discovered it is possible to access one’s historical electricity consumption as a graph…..  a bit like the one on the back of the bill, only going farther back.  It’s limited to 27 months, but it makes for some interesting analysis, and I thought I’d share it with you.

Since we moved into this house, our consumption was consistently around the 4kWh/day mark.  In the Nov 2009 quarter, a noticeable increase to almost 5 kWh/day can be seen, and then another rise to maybe 5.5 is evident in the following quarter.  At that stage, I smelled a rat, and immediately tested our ageing fridge to discover it was basically stuffed, running for much longer than it used to.  I remember owning an even older fridge once that ran non stop, burning 2kWh/day all on its own!

So it was during the following quarter that we took the step of replacing it with our “cool idea”.  Because the bars in the chart cover a period of three months, there’s no knowing when the reduced consumption occured, but it’s very obvious.  Down to perhaps 3.5 kWh/day.  Then over the next period, we also got rid of the PC and the old TV, reducing those appliances’ consumption from ~280W to 70W, and this is where we lowered our daily useage to the 2kWh/day mark.

There’s a slight uptick in the Aug 2011 quarter, and that was caused by starting the second freezer after we killed our pigs.  The next downturn in the current “bill” can only be caused by the three LED lights in the kitchen….. which surprised me because I would not have thought the difference would have been that noticeable.   But then again, when you do the maths, 3 x 6W  (saving) x 6hrs = 108Wh/day, and that drop could well amount to 0.1kWh/day

The last bill came in at $642.98 in credit…… and I will add it to this post when I get around to scanning it.

The disappointing bit of news about all this energy stuff was that our Sunteams inverter died, again.  This is the third time in just over twelve months, but at least this time I only had to wait ten days for a replacement instead of the 6 weeks earlier.  I’m starting to wonder how many we will go through before the five year warranty runs out!

I recently bought one of these from Aldi (can’t recommend it enough) and I’ve just put our washing machine on it for the first time, and the most power it uses while spinning at full noise is 375W.  While washing, it only uses 100W.  Of course we only wash in cold water.



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