App to Monitor Electrical energy Usage

I got bills for Rs 1998 in November, Rs 2547 in December and Rs 3011 in January. Was the increase due only to some increased usage in winter? After all, hot water geysers probably gobble up more energy than any other device!  Air conditioners may use more energy, but we do not have one. Our cooking is mostly done with a gas stove.

There are allegations that meter readings as processed by the utility company have errors in them and are sometimes subject to fudging. More than all this, I would worry about thoughtless consumption of what is a scarce resource in India. Sometimes we let a geyser run for a couple of hours for no reason. Sometimes we let lights stay on unnecessarily. The best remedy for this would be to give homes a true power meter which shows the instantaneous power consumption in watts or kilowatts. It could also show the accumulated charge for the current billing period, displaying the number of chargeable units and an estimated charge in the appropriate currency. In most cities, the charging is done on a slab basis indicating the rate per KWh as a function of the number of units consumed. It may be sufficient if an average rate/KWh is used to display estimated charges, on the basis of the average consumption in units per month in the house.

The basic idea is to create awareness of consumption of a scarce resource and to enable the user to manage consumption intelligently, reducing energy wastage. 

There is no standard for an interface for a device like this to be connected to house wiring. One possibility is to see if a fuse holder can be modified so that it continues to work as a current limiter and at the same time gives a measurement of instantaneous current being drawn. However, this could raise issues of safety and legality.

Would a simple display unit integrated into the sensor holder do? It would be the most inexpensive solution. Or would a cell phone be better to tap the computing and display capabilities of the cell phone? These are design issues to be tackled.

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