“When it comes to measurement, the solar guys have it easy. Solar panels are connected to an inverter that changes the current from DC, created by the panels, to AC which is used in our homes. In most cases the inverter also has the ability to measure the output of the solar array. Therefore, it’s very easy to see how much you are saving with solar P.V. as you can track output and compare it to usage.
Measuring energy efficiency, however, is a different story. Unlike solar, energy efficiency (EE) upgrades typically involve installing several different measures that work in concert to provide savings. To physically measure the individual effects of your efforts, you would need to have a meter for every measure, and then somehow combine all of that information in order to provide a summary of your savings. As you might imagine, that is not really possible.”
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