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#Kwh to unit calculator code
#Kwh to unit calculator plus

This means that the average household that consumes 1000 kWh per month will pay $128.80 for electricity, and residential customers who use 2,000 kWh of electricity in a month will have to pay $257.60. The average cost of electricity in the United States is 12.88 cents per kilowatt hour (kWh). What is Cost Per KWH?Ĭost per kWh is a measure of the cost per unit power consumed by electronic devices. To calculate the cost per kWh, divide the total cost by the power consumption in kWh.

Where CPKWH is the cost per kilo-watt-hour.

You have an attribute in the utility_meter sensor last_period so you don’t need any automation. In what respects to floating point overflow, it is using python Decimal class to avoid those issues, but there are always rouding errors. Utility_meter will sum the variances of the source sensor, so it is not much bothered if a reset occurs (it will discard negative variances, that occur when a reset happens). You have a good explanation in wikipedia of the various methods and since this is a GENERIC integration sensor, it makes much more sense to use the Trapezoidal method. We can discuss on the virtues of both methods, but HA documentation clearly states what the integration sensor is about, which method it uses. You are applying the “Left Riemann Sum” method while the integration sensor is applying the “Trapezoidal Riemann Sum”. I don’t agree it’s 7.5 kWh… by my calculation it’s 8.33 kWh (It’s only 7.5 if you apply the “Left Riemann Sum” method) The installation instructions are provided in the file header.

Another example could be a baseboard heater which pulses ON and OFF.įor those who want a more accurate flow, I provide this link to my python script. My power source is my gas furnace which ramps up the burners in three discrete steps until the temperature set point is satisfied.

#Kwh to unit calculator plus

This is why the above testcase error is plus 12.8% It is adding triangles of energy between the staircase power levels. The Integration Sensor uses Trapezoidal rule for integration! While this is OK for continuously variable power sources it adds energy that does not exist for pulsating or staircase power waveforms. Now here is the big reason why I don’t like the Integration Sensor to Utility_Meter flow.It resets to zero on the hour so you would need a automation to sample the hourly sensor output one second before each new hour. You would expect it to change on the hour. The hourly sensor output from the Utility_Meter changes throughout the hour.This does not seem to bother the Utility_Meterīut I wonder if there is a floating point overflow or loss of accuracy when subtracting large floating point numbers. The integration sensor output never resets.Integration Sensor to Utility_Meter flow: 8.463 kWh, error = 12.8%Ĭustom Python Script: 7.5113 kWh, error = 0.15%Ĭlearly, there are issues with the Integration Sensor to Utility_Meter flow. I hope you agree the known good result is 7.5 kWh My power waveform was simple so that I could do my own integration calculation I created a test power waveform and fed that to the Integration Sensor to Utility_Meter flow I’m back to explain why the Integration Sensor to Utility_Meter flow has issues.

#Kwh to unit calculator code

If you are feeling adventurous, you could pull the code from either (or both) of these and use them as custom components probably until they get merged. On a reset an attribute will store the previous counter, providing the means for comparison operations (“did I spend more or less this month?”) From a User perspective utility meters operate in cycles (usually monthly) for billing purposes, this sensor will automatically reset the counter based on the configured cycle. This sensor does an integration of Power and time in order to measure energy consumed in kWh (standard energy measurement unit)Ī utility meter sensor provides functionality to track consumptions of various utilities (e.g. Sometimes a device only provides power information (measured in W or kW). Hopefully they are accepted and merged… eventually. There are two components with open pull requests that seem to meet your need.