Calculate your household energy usage
Understanding how to calculate energy consumption can help you lower your electricity usage and monthly bills. Every device or appliance in your home uses electricity, measured in kilowatt-hours (kWh). Your power consumption level is the total kWh used in your home.
Your energy provider charges you for every kWh of electricity you use every month. The best way to lower your energy bill is to find ways to decrease the electricity you consume. By tracking your household’s energy usage, you can learn about what affects your total consumption and find opportunities to cut down your electricity usage.
How to calculate power consumption in your home
Your monthly energy bill accounts for how much electricity you use to power your appliances, electronic devices, HVAC system, lights, and more. You can check your past electric bills to estimate your typical energy usage.
You can manually estimate your energy usage by looking at which appliances and devices use the most power in your home and calculating their overall cost to use. The costs associated with heating, cooling, and lights can be harder to manage since they’re running most of the time, but it’s easy to find out how much your additional devices add to your total power consumption. Once you’ve done that, you can adjust your usage — and lower your bill — by unplugging those devices or using them less often. To manually calculate your power consumption, use the following steps:
- Calculate the watts your devices and appliances use per day.
- Add up the total amount of watts.
- Convert the watts to kilowatts. There are 1,000 watts in one kilowatt.
- Estimate the cost by multiplying monthly kilowatts by your electric rate.
Finding the wattage of a device
Most devices have a label listing the number of watts they use. The wattage label can be found on the device (usually on the bottom or back) or in the owner’s manual.
If you can’t find the wattage label, there are a few other ways to locate this information:
- Purchase a wattage measuring device which displays the wattage of a device when you plug it in.
- Contact the manufacturer with your device’s model number.
- Look up your device and model number online. Most manufacturers list the wattage of their products on their websites.
We’ve also provided a list that shows the average wattage of common household devices. Though the wattage of your particular device may vary, this can give you a rough estimate.
How to calculate kWh per month
The following sections outline how to calculate your home’s monthly kWh usage, including an example to demonstrate how your monthly kWh usage contributes to your overall energy bill.
Calculate daily watt-hours
To calculate your energy consumption, multiply an appliance’s wattage by the number of hours you use it in a day (the watt-hours).
Device Wattage (watts) X Hours Used Per Day = Watt-hours (Wh) per day
Example: A 170-watt television used three hours per day
170 watts X 3 hours = 510 Wh/Day
Converting watt-hours to kilowatts
Your electricity bill is measured in kilowatt-hours (kWh), not watt-hours. One kilowatt is equal to 1,000 watts. To calculate how many kWh a device uses, divide the watt-hours from the previous step by 1,000.
Device Usage (Wh) / 1,000 (Wh/kWh) = Device Usage in kWh
Example: A television using 510 Wh of electricity per day
510 / 1,000 = 0.51
How to find monthly energy usage
Now that we know how many kWh the appliance uses per day, we can estimate that usage over the course of a month. Multiply the daily usage by 30 days to calculate the approximate monthly kWh usage.
Daily Usage (kWh) X 30 (Days) = Approximate Monthly Usage (kWh/Month)
Example: A television using 0.51 kWh of electricity per day
0.51 kWh X 30 Days = 15.3 kWh/Month
In this example, a 170-watt television you use for three hours every day accounts for 15.3 kWh of energy per month. This is the television’s monthly energy consumption. The next section will cover how that translates to your electricity bill.
How much do appliances cost on my electricity bill?
To estimate how much an appliance adds to your electricity bill, check your latest bill to find the price you pay per kWh, otherwise known as your electric rate. To determine how much your appliances cost per month, multiply your electric rate by the estimated monthly usage from the previous step.
Monthly Usage (kWh) X Electric Rate ($/kWh) = Approximate Cost per Month
Example: A television using 15.3 kWh/Month with an electric rate of 16 cents per kWh ($0.16/kWh)
15.3 kWh X $0.16 = $2.44/Monthly Bill
This television would cost $2.44 per monthly energy bill based on these calculations. While that might not seem like much, the appliances and devices in your home can add up quickly.
Remember, your appliances and devices only account for part of your energy bill. Your bill also includes heating, cooling, and lighting, which add to your costs. If your home has a smart meter, you can track your usage and multiply the kWh for that month by your electric rate (like we did in the most recent step) to get a more accurate bill estimate.
The following table shows the categories that consume the most energy in the average home, according to the Energy Information Administration (EIA).
| Category | Percentage of Energy Usage |
|---|
| Space cooling | 16.2% |
| Space heating | 15.9% |
| Water heating | 11.4% |
| Refrigerators and freezers | 6.9% |
| Lighting | 4.4% |
| Televisions | 3.5% |
| Computers | 2.3% |
| All other devices and appliances | 39.4% |
Calculating your energy bill comes down to knowing your usage and the price you pay for energy. Our energy experts recommend a fixed-rate energy plan for predictable energy bills. Since your rate remains the same under a fixed-rate plan, you can budget more easily for your energy costs. Enter your ZIP code on this page to explore available fixed-rate options.
Seasonal energy trends
There are certain times of the year when you will likely use more energy, and your bill will increase as a result. For most people, this comes during summer and winter, when extreme temperatures require you to rely on air conditioning or heating. Taking steps to lower energy consumption and increase energy efficiency during high-usage periods can help lower electricity bills.
Here are a few energy consumption tips from our experts to help you save electricity in your home and potentially lower your energy bill: