Category Archives: my electricty challenge

electricity challenge round up

Back in August 2009 I set myself an electricity challenge – to use a maximum of 12kWh (average) a day for the last four months of the year.

2009 is well and truly over, and after countless number of electricity meter reads, I have finally collated the results and have them ready to present.

Firstly – some background on my usage. For the first eight months of 2009, my electricity usage was 14.88 kwh/day:

Electricity usage graph

Now for the final four ‘challenge’ months – September to December. I will preface the result with “I tried really hard”, but unfortunately i did not succeed. My average usage for this period was 12.62 kwh/day:

Electricity usage graph

So close! Under 12 would have been nice, but it is something to work towards. I will report back soon on my usage for the first quarter of this year (a.k.a the “air conditioner” quarter), to see if I can achieve the target.

I also think I need to take a new approach to reducing my usage. The odd light change to CFL or sleep period for the laptop will not achieve the “less than 12” target. I need to do something about the always on/big consumers – the fridge, the freezer, the web server or the media center PC. One of these boys has to undergo a big change!

I am also putting together a energy meter, to allow me to monitor my usage better (rather than relying on myself to read the meter!). So far I have a CT clamp and I am working on a solution that involves a PICAXE (or an arduino) and an 433Mhz RF transmitter. More on this soon.


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my electricity challenge – week 1

One week after laying down my challenge, it is time to see how it is coming along. To re-cap – I have set myself a challenge to use less than 12 kWh of electricity per day (on average), by the end of this year.

Each night after work this week I have read my meter, and using these readings I have been able to calculate my daily usage, which I now present below in a pretty, interactive graph.

As you can see I got off to a great start – the first two days were below my target. However after that it all went belly up, and I am unsure why. The only explanation I have for the difference between the days is that the (electric) oven was used to cook dinner a couple of nights.

My average for this week was 14 kWh per day. Below the average on my previous bill, but 2 kWh above my target!

I have also tried again to minimise my usage this week. My laptop used to be on most of the time however it now suspends and sleeps after 1 hour of being idle, so it is off whilst I sleep and work. I have also replaced another two halogen downlights with the CFL type.

Hopefully these changes will help to bring my usage down next week, as I am running out of ideas. I really don’t want to go back to washing dishes in the sink – I like the dishwasher too much!

my electricity challenge

For the last 12 months I have been trying to reduce the amount of electricity I use at home. It all started in August 2008 when my electricity bill arrived and my average daily usage was 19.54 kilowatt hours (kWh)!

19.54 what? To put this into context, in 2003 the average daily usage for Victorian households was 6,398 kWh, or 17.48 kWh a day. Whilst I am certain that figure has gone up in the last five years, I imagine I am using at least (if not more than) the average daily household usage. With only two adults in my average sized home, this is excessive!

Immediately I forked out for compact fluorescent lights (CFLs) to replace my energy hungry incandescent globes. I also reshuffled some hard disk drives between two computers that were on 24/7 so that one could be shut down and only powered up when needed. The last change was to replace two of the hard disk drives in my 24/7 media centre PC with one ‘green’ hard disk drive.

These changes resulted in a welcome surprise on my next electricity bill. My average daily usage was down to 15.33 kWh – a 21% decrease. By being energy conscious (switching off lights and appliances when not needed) the third bill came in at 13.47 kWh – another 12% decrease.

It was now summer 2009 – air conditioning season. I have a split system inverter air conditioner, and I decided I would monitor my electricity usage more closely to see how much it used. On the infamous Black Saturday I consumed 24.56 kWh, and probably played my part in the blackouts that followed.

Over the next few months I monitored my usage every week or so, with my average daily usage coming in around 15 kWh. After returning from overseas in July, I decided it was time to reduce my usage even more.

Using a watt meter I checked all the appliances in my house to see what was using… errr… watt. The biggest users were my media center and web server PCs (~1.6 kWh a day each), and also the fridge in the kitchen (1 kWh a day) and the freezer in the garage (1 kWh a day).

The biggest surprise came from my study, where I have a PC and printer that is rarely used, and is shut down when not in use. I estimate that it is powered up every 3 weeks, however the standby power that it consumed whilst off was high – 40 watts or 0.96 kWh a day! It is now turned off at the power point, resulting in 0 kWh a day.

Other appliances I tested included the front loading washing machine (4 watts when switched off at the machine) and the cordless phone base station (6 watts).

The final change I am making is to replace the last of my energy hungry lighting – the eight 50 watt halogen downlights in my kitchen and dining area. In total they consume 0.4 kWh per hour, or 1.6kWh a day if they are on for four hours each night. I have had two of them replaced with CFL type downlights that consume only 11 watts each as a trial, however I am already sold and will organise to have the other six replaced ASAP.

The changes I have made in the last month have brought my usage down to around 13 kWh a day. I have set myself a target of 12kWh a day, which I think can be easily achieved, will save me money in the long run, and reduce my need for the grid.