Thursday, January 20, 2011

Getting Green With It All....

I live in an all-electric powered home in the southeast US. It's a relatively recently built, well designed and energy efficient home. In November 2009, we had a problem with our heat pump - it would not hold refrigerant - and it was traced to a factory defect in the "A-coil", which is the part of the heat pump that transfers heat to-or-from the interior air, being blown over the A-coil.

The local firm that installed the heat pump then replaced the A-coil. Remember, this was early November, 2009, beginning of the winter "heating season" here in the US. As a result of installing the new A-coil, the firm made mistakes that compounded themselves over the next three months. In the meantime, we had a very cold January, and the problems they caused with the heat pump developed a situation where the "emergency heat strips" were the only means of heating we had - the heat pump itself would not, well, "pump heat".

Dealing with the vendor was one bad problem, but then we got the power bill the next month for the runaway power consumption of the unit - and it was about $120 higher than normal for that time of year, even for an exceptionally cold January. The impact of the charge was significant, on top of the hundreds of dollars spent with the vendor. The sting of it all was that I had no clue the heat strips were coming on continuously until I got the bill.

Being an electrical engineer for all of my adult life, this was an unacceptable situation. Not understanding the power draw of all the circuits in my house was the key to recognizing the problem in the first place. Also realizing that with every passing day, I was losing data essential to gaining that understanding, I was willing to go out and buy something I could simply and quickly attach so I might monitor my whole-house power consumption.

With all the talk about "going green" and "reducing your carbon footprint", knowing how much energy you use in your home would be a vital, fundamental step toward saving energy, money and carbon. I expected to find at least a dozen different devices that could measure electric power draw by a home, a full range of products at all different kinds of prices.


What I found on the internet was really only two viable products: "TED 5000" (The Energy Detective) and something called "eMonitor" from Powerhouse Dynamics. The TED 5000 fit the bill for a rapid whole-house solution at about $300. Not too bad. But the eMonitor, now that was the ticket: whole house, all-circuit monitoring. It looked mature, well-made and highly capable. But to implement the eMonitor product at my home, I'd have to buy two of them, a "larger" and "smaller" version of each, to install on both breaker boxes here at the house. Total would come out to roughly $2000. And to make matters worse, when you buy the eMonitor, you send your data to them, and they keep your data in their "cloud". The initial price of the unit includes a two-year "subscription". After that, you've got to pay an annual fee to keep the power measurement goodness running.

That was enough to completely end the idea for me. I'm not interested in putting my data in your cloud and paying for it, thank you very much. I want to keep my own data so I can improve the user interface, add features when I'd like, and fine-tune the sensitivity of the unit to match the power draws of the circuits in the house.

So, the quest begins: to design, build and implement, first a whole-house power monitoring solution, then from there, move on to a whole-house power monitoring system that can track energy usage on all circuits. And to do it for well under $2000.

Follow along with me as I research the problem itself, the components needed to do the measurement, and develop a solution that takes the measurement and brings that data all the way to your computer screen, where you can look, learn, and act.

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