Calculate Your Power Consumption

Understanding how much electricity you use to power your home can help you lower your energy bills. Why? Because the amount of energy you consume – measured in kilowatt-hours (kWh) – is how electricity companies calculate the amount of money to charge you on your electric bill each month.

Every device or appliance in your home consumes a certain amount of electricity. The kWh each device consumes, combined with heating, cooling, and lighting, adds up to create the total amount reflected on your bill. Knowing how much power you use can help you cut back on your consumption level and, in turn, lower your monthly electricity bill.

So, how can you calculate the energy consumed in your home? You can use an energy usage calculator or follow an easy formula to determine the kWh used by your devices:

1. Find the watts each item consumes per day.
2. Convert the watts into kilowatts. Every one kilowatt is equal to 1,000 watts.
3. Calculate how many kilowatts each item uses per month.
4. Determine the cost of each item by multiplying the monthly kilowatts by your electricity rate.

Determining the wattage of a device is the first step to calculating how much it costs to operate. Most devices have a label that notes how many watts they use. This label is often posted on the bottom or the back of the item, or is noted in the owner’s manual. 

If you aren’t able to find the wattage label on a device, you can look up the item and its model number online, contact the manufacturer, or use a wattage measuring device.

Once you’ve found the item’s wattage, you will need to multiply that number for the hours you use it each day. 

Calculate watt-hours per day

Wattage x Hours Use Per Day = Watt-hours (Wh) per Day

Example: A 150-watt computer monitor used 4 hours per day

150 watts x 4 hours = 600 Wh/Day

How to Convert Watt-Hours to Kilowatt-Hours

Your energy bills are measured in kilowatt-hours (kWh), not watt-hours (Wh). So, to understand how much a device is costing you on your bills, you need to convert watt-hours to kilowatt-hours. One kilowatt is equal to 1,000 watts. Here’s how to convert Wh to kWh.

Device Consumption(Wh) / 1000 (Wh/kWh) = Device Consumption in kWh

Example: A computer monitor using 600 Wh of power per day

600 / 1000 = 0.6 kWh per day

Estimating Monthly Energy Usage

You are charged for electricity monthly, so we now need to take the kWh per day and convert it into a monthly kWh level. To do this, we can multiply the daily amount by 30 days to estimate a monthly average.

Daily Usage (kWh) x 30 (Days) = Approximate Usage in a Month (kWh/Month)

Example: A computer monitor using 0.6 kWh of power each day

0.6 kWh x 30 Days = 18 kWh/Month

In our example, a 150-watt computer monitor that you use for 4 hours each day would add up to 18 kWh per month. This is the computer monitor’s electricity consumption level.

So, how does a device’s energy consumption translate into your monthly electricity bill? The last step is to multiply the device’s monthly usage by your electricity rate. You can find this rate listed on your energy bill.

One thing to note – if you are enrolled in a variable-rate energy plan, the rate you pay for electricity can change from month to month. This makes it trickier to calculate future energy bills because you can’t know whether or how much your rate will vary. If you are signed up for a fixed-rate plan, you can estimate your monthly bill more easily because the rate you pay will not change.

To figure out how much a device costs per month, multiply its monthly electricity consumption (the number that we found in the last step) by your energy rate.

Monthly Usage (kWh) x Electricity Rate ($/kWh) = Estimated Monthly Cost

Example: A computer monitor that uses 18 kWh/Month with an electricity rate of $0.12/kWh

18.00 kWh x $0.12 = $2.16/Month

Based on this formula, the computer monitor in our example would cost about $2.16 on your power bill to operate each month. This might not seem like a lot at first glance, but remember that every device and appliance consume electricity – and that doesn’t include heating, cooling, or lighting.

If your home has an electric meter that you can read, multiply the number of kWh for that month by your electricity rate using the same steps above to get a more accurate estimation of your bill. You can also estimate a monthly bill average by adding up the total amount from electricity bills and dividing by the number of months. This will give you an idea of your average monthly power bill amount.

The main reason why most consumers want to understand their electricity consumption is because they want to lower their energy bills. Knowing which devices in your home consume the most power is the key to managing your usage levels.

There are several ways that you can lower your electricity consumption. But first, it’s worth noting that if you are signed up for an energy plan that has a high electric rate, reducing your consumption levels will only do so much. If you live in a deregulated area, it may be time to search for a plan with a lower rate. You can use the Choose Energy marketplace to find and compare electricity plans in your area. There is no cost to use our marketplace and the rates we show are all-inclusive. Enter your ZIP code above to explore available rates and plans in your area.

Here are a few of the easy steps you can take to reduce your electricity consumption:

• Choose Energy Star-certified appliances. Energy Star is a government-run program that sets efficiency standards for appliances. In order to be Energy Star-certified, appliances must consume less electricity compared to older or non-certified models. For example, Energy Star-certified refrigerators consume 15% less energy than non-certified refrigerators. 
• Lower your water heater’s temperature. Water heaters account for about 19% of the total energy consumed in the average household. Simply lowering your water heater’s temperature to 120 degrees Fahrenheit can greatly reduce your total energy consumption and lower your electricity bill.
• Perform regular maintenance on your home. Check your windows and doors for gaps that could let air in or out. You should also make sure to have a licensed professional check your HVAC system at regular intervals, since heating and cooling normally make up about 50% of a home’s energy usage combined. 
• Install a smart thermostat. Smart thermostats make it easier to check and maintain the temperature of your home. During the winter, the most energy-efficient temperature for your thermostat is 68 degrees Fahrenheit. In the summer, it’s 79 degrees. 

Managing your home’s energy consumption can help you lower your monthly electricity bill. You can learn more about the energy industry and how to find the right electricity plan with the following guides: 

• Energy buying guide
• How to switch energy providers
• Tips to lower your energy bill
• What is energy deregulation?
• The Choose Energy Data Center