Your meter shows a running total in kilowatt-hours, not a rate. To find out what you used over a period, read it twice and subtract. Digital and smart meters show the number directly. Dial meters need a trick: read the five dials right to left, take the lower number whenever a pointer sits between two, and remember that adjacent dials turn in opposite directions.
That second reading is where the value is. Once you can take a reading, you can run an elimination test that finds exactly what is drawing power in your house while you are not using anything — which turns out to be a surprising amount.
Reading a digital or smart meter
An LCD display shows a number, typically five to eight digits, sometimes cycling through several screens. Read left to right including leading zeros, and ignore anything after a decimal point.
Some meters cycle between displays: total consumption, current demand, and on solar-equipped homes, energy exported. If yours cycles, note which screen you read so the next reading is comparable — this is the most common source of confusing results.
Smart meters are digital meters with a communications module that reports to the utility automatically, usually every half hour. Your utility’s app or web portal will normally show that half-hourly data, which is far more useful than manual readings if you have access to it.
Reading a dial meter
Five small dials, each with a pointer. The rules:
- Read right to left.
- Adjacent dials rotate in opposite directions — the first clockwise, the next counterclockwise, alternating. Look at the numbering on each face to see which way it runs.
- When a pointer sits between two numbers, take the lower one.
- When a pointer looks exactly on a number, check the dial to its right. If that one has passed zero, use the number. If it has not yet reached zero, use one lower.
That last rule is where nearly all misreadings happen.
Finding phantom loads: the overnight test
Standby power — devices drawing electricity while switched off or idle — can account for up to about 10 percent of household electricity use. It is invisible on a bill and easy to find with the meter.
- Take a reading late at night.
- Turn off everything you can and leave the house running as it normally would overnight.
- Take another reading in the morning, and note the hours elapsed.
- Subtract, divide by hours. That is your baseline draw in kW.
Multiply by 8,760 to get an annual figure. A baseline of 0.15 kW — not unusual — is around 1,300 kWh a year before anyone has switched anything on.
To find the culprits, repeat the test with one circuit switched off at the breaker, or work through suspects with a plug-in energy monitor. The usual offenders are set-top boxes and DVRs, game consoles in instant-on mode, older desktop PCs and printers, always-on chargers and power bricks, secondary fridges and freezers, and towel rails or heated devices left on a timer nobody set.
The holiday check
Easier than the overnight test if you have old bills: find a billing period when you were away. If usage over that period sits at 40–50 percent of a normal period, a substantial fraction of your electricity is being consumed by things that run regardless of whether anyone is home.
Why your bill and your reading don’t match
Common and usually harmless. Utilities frequently issue estimated bills between actual reads — the bill will say so somewhere. Submitting your own reading corrects it. Meters also roll over from 99999 back to zero, and the billing period rarely matches the calendar month you assumed.
If the discrepancy is large and persistent after a genuine read, ask for a meter test. Faults do occur, though they are rarer than billing estimates.
Turning readings into something useful
A single reading tells you nothing. A weekly reading, written on a note stuck inside a cupboard, tells you a great deal within a month — whether a change you made worked, when your consumption climbs, and what a cold snap actually costs.
Two things worth measuring this way, because both are large and both are free to adjust: your water heater’s set temperature, which runs continuously in the background, and heating and cooling behaviour, where using ceiling fans properly lets you move the thermostat several degrees without anyone noticing.