Saving energy with a netduino – results
Back in February 2011, I built an automated gas water heater regulator using a netduino micro-controller to save some energy with our old gas water heater. There was much debate among Hack A Day and Channel 9 readers about the effectiveness of this hack and its ability to actually save energy. As promised, I am now reporting the results of the experiment.
Puget Sound Energy, our energy provider, is kind enough to track our energy consumption and makes the data available through their web site. I ran two reports to compare our natural gas usage between March and April 2010 and the same time period in 2011, including the outside temperatures.
Puget Sound Energy Charts - Natural Gas Consumption
March-April 2010
March-April 2011
Conclusion
Compared to 2010, the netduino-powered Water Heater Controller saved 20 therms between March and April 2011 even with lower outdoor temperatures than the previous year. In WA a therm costs ~$1.19. So this represents a $23.80 saving. Not bad for a weekend project 
I wish I had more data to show, unfortunately, the water heater died on us the second week of April with a completely rusted out bottom. C’est la vie…
Death by "rusted out bottom"
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Ack! Proof that Netduino causes rust!!!