How many watts does a computer use?

While not as power-hungry as appliances like air conditioners or washing machines, it's important to know how much electricity a computer uses when you're looking at your whole home's energy usage.

Generally, computers use between 30 and 70 watts (W) of electricity, depending on the model. Computers usually use between 3 and 5 amps and connect to a 120-volt outlet. Larger desktop and gaming computers can use up to 500 W.

How much you use your computer has the biggest impact on how much electricity it uses over time. Assuming an average computer needs 50 W to run:

• Using your computer for 6 hours per day results in 2.1 kilowatt-hours (kWh) of electricity per week, 9.1 kWh per month, and 109.5 kWh per year.

• Eight hours per day of computer usage comes to 2.8 kWh per week, 12.2 kWh per month, and 146 kWh per year.

• On the upper end, running a computer for 10 hours per day uses 3.5 kWh of electricity per week, 15.2 kWh per month, and 182.5 kWh per year.

Different wattage computers use different amounts of electricity over the course of a year. Assuming you run your computer an average amount (8 hours per day), here's how much electricity you'll use over the course of a year for different wattage computers:

How many watts do different computers use in a month and a year?

We'll mostly be referring to the electricity used by computers in terms of kWh in this article. The reason is simple: your electric bill is measured in kWh, and you get charged based on the kWh of electricity you use per month!

When you get your monthly electric bill, you only see the total amount you're charged, not how much each appliance contributes to your final bill. Based on an average wattage of 50 W for computers (amounting to 146 kWh/year) and using state average electricity rates, here's how the cost to run a computer pans out over the course of a month and a year:

Monthly and yearly costs to run a computer by state

Note: average electricity rates are based on October 2021 data from the U.S. Energy Information Administration (EIA).

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Calculate how much energy your own computer uses

If you want to know how much electricity your computer uses (or at least is supposed to use), take the estimated yearly electricity use in kWh – this is probably your best bet for an accurate number. Simply multiply this number by the average electricity rate in your area to get an estimate of how much you spend to power your computer each year. For an estimated monthly cost, divide the estimated yearly cost by 12.

What's the best time to run a computer?

If you're on a time-of-use (TOU) rate plan, you are charged different amounts for electricity throughout the day. In general, it's cheaper to use appliances during "off-peak" hours, which are usually overnight.

What size battery do you need to back up a computer?

All popular home batteries can power a computer: most lithium-ion batteries like the Tesla Powerwall or Generac PWRcell have a power rating of 4 to 5 kW or higher and 10+ kWh of usable capacity. Computers use about 50 W (0.05 kW) of power at any one time, meaning a battery will be plenty suitable for backing up and powering your computer, even for long periods and with more powerful computers.

How many solar panels does it take to run a computer?

On average, computers use about 50 W of electricity to stay powered. With solar panels rated at around 350 W, you'll be able to power a computer with one solar panel easily.

What are ENERGY STAR appliances?

ENERGY STAR is a U.S. government-backed system that certifies how energy-efficient appliances are. If an appliance is better than the average appliance in its category by a certain amount, it is labeled as "ENERGY STAR certified." ENERGY STAR appliances cost less money to run, given that they are more efficient with the electricity they use.

Solar savings vary widely, and your unique savings depend on factors like electricity usage, location, and electric rates and plans. In general, most homeowners can expect to save somewhere between $10,000 and $30,000 over the lifetime of a solar panel system. On average, it takes between 7 and 8 years for most homeowners who shop for solar on EnergySage to get their solar panels to pay for themselves.

Going solar is one of the most effective ways to reduce or eliminate your electric bill, and you should make sure you are getting several quotes from reputable installers before you decide to move forward. Visit the EnergySage Marketplace to get solar quotes from installers in your area and begin comparing options.