Real-Time Expressions: Compute Energy Costs


Compute energy costs from Watts logged. This operation will use a combination of the summary statistics tile view and real-time expressions.


Tile Type: Summary Total (Events measured in Hours).

Real-Time Expression:
=[data stream]/1000*<cost per kWh>


A data stream from a smart outlet, Kitchen Outlet(power), is logging data in Watts. This data stream needs to be converted to cost.

Add a tile and select the Tile Type to be Summary. Under the Summary Value drop-down, select Total. There are two options under Total Basis. Events by value will simply add up every value in the data stream into a single summation. In the example above, there have been 33,953,657.80 Watts logged over time.

Watts needs to be converted to Watt-hours (Wh). To do this, simply select the second option under Total Basis, Events measured in Hours. In the example above, there have been 2,692.40 Wh used. 

Next, convert Wh to kWh by using a simple real-time expression to divide by 1000. In the example above, the expression is:
=[Kitchen Outlet(power)]/1000

The final step is to multiply the total kWh by the your electricity rate, typically expressed as the cost per kWh. In the example above, the kWh rate is $0.10. The final expression is:
=[Kitchen Outlet(power)]/1000*0.10

The final computation for the total energy costs for the kitchen outlet is $0.27. Selecting specific time ranges in the timeline will automatically update this calculation for the energy costs in that time range. 

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