Reading Your Power Meter

Why read your power meter? Because it can help you understand how much electricity your household is using.

Reading your meter is how your local power company calculates your bill. By learning to read it yourself, you can take steps to save energy and reduce your bill.

1. Understanding Kilowatt-Hours

Your power meter measures electricity in kilowatt-hours, which equals 1,000 watt-hours and is often represented as kWh.

A 100-watt light-bulb burning for 10 hours uses 1,000 watt-hours, for example.

100 watts x 10 hours = 1,000 watt-hours = 1 kWh.

Ten 100-watt light-bulbs burning for 1 hour also use 1,000 watt-hours.

100 watts x 10 bulbs x 1 hour = 1,000 watt-hours = 1 kWh.

2. Reading Your Meter: Digital or Dial

Meters track how many kilowatt-hours your household has used. Digital meters simply display the number of kilowatt-hours, so reading those is straightforward.

A dial meter can seem confusing at first, but once you get the hang of it, it’s easy to read. Dial meters have five dials, each numbered 0 through 9. Some move clockwise, others counterclockwise, though you don’t need to worry about that.

Starting with the dial at the left and working your way right, write down the number for each dial:

  • If the hand is between two numbers, write down the smaller number, even if the hand is closer to the bigger number.
  • If the hand is directly on a number, look at the dial to the right. If that hand has passed 0, write down the number the left-hand dial is pointing to. If the hand on the right dial is still between 9 and 0, write down the last number the dial on the left passed.

Read left to right, the numbers represent how many kilowatt-hours your house has used.

3. Now What? Calculating Usage

So what can you do with this information? To start, you can find out how much electricity you’ve used since your last bill. Find the meter reading from that bill and subtract it from the reading you just took to see how many kilowatt-hours you’ve used since then.

You can also determine the impact of running certain appliances or making changes in your energy use. Here are a few ideas:

Determine how much electricity it takes to run appliances like the washer or dryer. Check the meter before and then again after running them to find out. It may cause you to rethink running those small loads—or consider replacing older appliances.

Discover the impact of turning out lights and other small changes. Look at your meter daily for a while to get a sense of your typical use, or divide your monthly usage by 30.4 to get an average. Then spend a day or two making a conscious effort to turn off lights when not in use and follow other energy-saving tips. Check your meter to see the impact. Do the same experiment with turning down the thermostat in winter or turning it up in the summer.

Monitor the effect of energy-saving measures, such as replacing incandescent bulbs with CFL or LED bulbs. Again, you’ll need a baseline of your average use and then you can calculate how much energy you save once you make a change

Now that you understand how your bill is calculated, explore how you can save energy and money by taking simple steps around your home