How do I calculate my energy usage without Consumption Monitoring?

How to calculate how much energy your home uses, if you don't have Consumption Monitoring.

The easiest way to see how much energy your system uses is to have Enphase Consumption Monitoring installed on your system. Unfortunately, this feature may not be available for all systems, depending on the setup of your home's electrical panel.

However, with a little math, you can still calculate how much energy your home is using. First, let's take a step back and look at how energy is harvested by your system.

How energy is harvested by your system

The Enphase microinverter system will feed all energy harvested through your home’s main service panel. At the service panel, some of the energy harvested may be consumed by “loads” (energy users like appliances) in your home. The balance of the energy harvested will be backfed to the grid.

Even when the array is producing enough energy to power all the appliances in your home, some power may still be pulled down from the grid. This happens because electrons don’t care where they go! For example, if your refrigerator circuit on the service panel is physically close to the solar circuits in the service panel, your fridge may siphon off more of the harvested energy than other appliances whose circuits that are farther from the solar circuits. This might result in your pulling some power from the grid, even though doing the math, you didn’t need the extra energy. 

Harvested energy that is not used at the home is delivered to the utility. If you are a net-metering (NEM) customer, you are receiving credit from your utility for all the energy you backfeed to the grid. Using the example above, you’re not going to receive credit for all the solar power you generate, because some of it was consumed by your refrigerator before it got to the meter.  

How to calculate your total consumption

The total consumption in your home then, is the sum of what you purchased from the utility, and the solar harvest that was “used up” before it got to the meter. 

In mathematical terms the calculation is: 

Total Consumption = kWh purchased + (Enphase harvest kWh – net meter credit kWh) 
The math can be tedious, but the key concepts to keep in mind are that:
1) Consumption is not just the energy billed

2) Harvest is not just the energy credited

Learn more about Enphase Consumption Monitoring

When you have Enphase Consumption Monitoring installed, you can instantly see how much energy your home is using right within the MyEnlighten app:

The orange bars show how much energy the home has used consumed. If you're interested in adding Enphase Consumption Monitoring to your system, you can contact your installer to see if the feature is compatible with your electrical panel.


Related Categories: Your Enphase PV system