In January, our electric bill shows 1685 kWh. In February, 1259 kWh.

The bill shows usage back a year, it does seem as if heating season consumes a lot more power than the rest of the year, in spite of our central AC.

Heat is oil-fired hot water, has 5 zones, one of which is just pushing water to heat the hot-water tank next to the furnace. Could there be a problem with a pump?

Almost none of the lighting is incandescent, it's a mixture of CF and LED. Ovens in kitchen are electric. I don't run a woodshop, or a printing press, or and other electric machinery of note. And I don't bake that much.

How could I go about learning something about what's consuming power? We probably used more of the heating system in January (it was cold, and we were home with an injured member of the household) -- but still, even 'usual' level seems high.

  • I think eating electrons somehow violates the law of conservation of matter.
    – bib
    Mar 5, 2016 at 17:24

1 Answer 1


What I did was contact my electricity supply and said "send me one of those energy monitor thingies free pronto"

Some months later it arrived.

I clipped the wireless current sensor around the main line/hot between meter and main-panel (consumer unit), inserted some batteries into the wireless transmitter and I was then able to see on the receiver/display unit how the power changed as I turned various things on and off.

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This particular unit display current usage and lets you look at averages for prior days/weeks/months but if you actually want to spend your own hard-earned money, you can buy energy monitors you can plug into a PC and do data logging, graphing etc.

  • If it comes with only a single sensor, how does it measure power used by both 240VAC and 120VAC appliances?
    – Johnny
    Mar 5, 2016 at 17:01
  • @Johnny: in parts of the world with split-phase supply I believe the monitors come with two current sensors. In the part of the planet where I live, almost all homes use 230 V single-phase for everything. I actually have a three-phase supply (3 x 100A x 230V) but only use one 230 V phase. Additional sensors can be obtained, depending on monitor. Mar 5, 2016 at 18:29
  • Ahh ok, that makes sense, I saw that the person asking the question was in the USA, but didn't think to check your location, and you're in the UK.
    – Johnny
    Mar 5, 2016 at 19:26

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