After a few weeks away, I’ve had another fiddle with the Python scripts I run to graph data from my Current Cost meter. You can see the results here.
Of note, I’ve switched from using the Google Graphs API to RRDTool. This is for two reasons – the Google graphs API just seemed a bit fiddly, even using PyGoogleChart, and rrdtool graphs just seem pretty easy to output. In addition, it means I get averaging for free and don’t have to manage the database.
I’m still using the Python I tweaked from Dale Lane, but I created an RRD based on Paul Mutton’s guidance and update it using a Python module for RRD from Corey Goldberg. Feel free to ask for a copy of the scripts.
For some reason my sqlite db update script liked to bomb out after a couple of hours, but this seems to be working fine and has been gathering data reliably for the last few days.
Of course the whole point of this isn’t just to make pretty graphs, but to try and do something about our consumption. I’m already obsessing about the graphs produced, and they’re making it easy to see when something’s left on – our ‘base load’ seems to be about 200W, so anything more than this means something’s on somewhere.
Our most obvious heavy power usage is the oven, at about 3kW, but there’s not much I can do about that other than cook more with gas – or eat more salad! It’s generally not on for long, so not the end of the world. Interestingly, the oven seems to heat up in under 10 minutes (solid power use, followed by intermittent bursts to keep it hot). I’d always assumed this to be longer, so that’ll save some time and money!
I’m also quite conscious of the fact we sit in the living room with a few 60W lights on in the evening for quite some time. They’re on dimmer switches so I’m now hunting for dimmable CFLs. The Megaman bulbs seem to come quite highly rated, but I’m not really sure how good they are. If anyone’s readig this and has some insight, feel free to leave a comment!
My next plan with the graphs is to work on aggregating daily/weekly data to show trending totals and ignore the short-term fluctuations, so that I can see how things are improving. When I get some time at home to myself I’m going to try and work out exactly where the 200W base load is going (NAS, router and Sky are the key candidates) and see if I can get it lower.