How Much Does It Cost to Run a Fridge, Dryer or Space Heater? One Line of Math Tells You

The U.S. Department of Energy’s Energy Saver guide prices any appliance with one line of arithmetic. Multiply its watts by the hours it runs each day, then divide by 1,000 to get kilowatt-hours, the unit your utility bills you in. Multiply that by your rate and you have the cost.

At 18 cents a kilowatt-hour, a space heater running four hours a day comes to about $32 a month. A laptop open all workday costs about 7 cents a day.

Working it through on a space heater

The 2014 edition of Energy Saver’s estimating guide put portable heaters at 750 to 1,500 watts. Put yours on its 1,500-watt high setting for four hours, and that’s 6,000 watt-hours, or 6 kilowatt-hours once you divide by 1,000. Over a 30-day month you use 180 kilowatt-hours, which at 18 cents each comes to $32.40.

The guide’s own worked example is a 1,500-watt electric kettle used about an hour a day, every day of the year. At an 11-cent rate it priced the year at $60.23. Run the same kettle at the July 2026 national average of 18.31 cents and the year costs $100.25.

Example: the inputs behind the cost chart further down. The ranges are from the 2014 edition of Energy Saver’s estimating guide, the last one to print a typical-wattage list.

The wattages and the 18-cent rate here are illustrative. For a real benchmark, the U.S. Energy Information Administration publishes average home electricity rates for every state, month by month, in its Electric Power Monthly report.

Before you price anything of your own, write down roughly how many hours a day you run it.

Find the watts on the nameplate

Energy Saver says you’ll usually find the wattage stamped on the bottom or the back of an appliance, or printed on a small nameplate. That figure is the most power the machine can draw.

A heater on its low setting pulls less, which makes your nameplate math a ceiling on the cost.

Some nameplates list amps instead of watts. In that case you multiply the amps by the volts to get the watts. Most U.S. appliances run on 120 volts, while clothes dryers and electric cooktops use 240. The guide’s example is a paper shredder rated at 3 amps, which works out to 360 watts.

For a big appliance, look for the yellow EnergyGuide label first. It prints an estimated yearly use in kilowatt-hours for that exact model, which saves you from guessing at hours, though not every appliance has to carry one.

Read the rate off your bill

Your bill shows how many kilowatt-hours you used and what each one cost. Many utilities split that price into two lines, one for supply or generation and one for delivery.

Add the per-kilowatt-hour lines together, and you have your rate.

Leave out the flat monthly customer charge, since you pay it whether the heater runs or not. If your plan has tiers or time-of-day pricing, use the rate for the tier or the hours when you run the appliance.

What you pay per kilowatt-hour depends a lot on where you live. In the EIA’s July 2026 figures, the national residential average was 18.31 cents, with Hawaii at 48.00 cents, California at 33.61 and Louisiana at 12.72. The same 180-kilowatt-hour month of space heating costs $86.40 in Hawaii and $22.90 in Louisiana.

Why a fridge doesn’t run all day

A refrigerator stays plugged in around the clock, but it cycles on and off as needed to hold the temperature inside. Energy Saver’s rule of thumb is to divide the plugged-in hours by three, which turns 24 hours into 8. With the 2014 guide’s 725-watt figure for a 16-cubic-foot frost-free model, that’s 5.8 kilowatt-hours a day and $31.32 a month.

That number runs high, because a nameplate shows peak draw.

The Association of Home Appliance Manufacturers reported in 2011 that a typical refrigerator used 462 kilowatt-hours a year by 2010. That’s 38.5 a month, or $6.93 at 18 cents.

For your own fridge, trust the yearly figure on its EnergyGuide label or in its manual over the nameplate math.

Five monthly costs side by side

A 3,000-watt dryer, near the middle of the 2014 guide’s 1,800-to-5,000-watt range, uses 90 kilowatt-hours over a month of one-hour loads. That’s $16.20. A 50-watt laptop open eight hours a day comes to $2.16.

Set the fridge’s nameplate estimate aside, and the heater and dryer are the two biggest bars. Both make heat.

When you go looking for a big number in your own home, start with anything that warms, dries or boils.

Standby power is a slow trickle

Plenty of devices keep drawing a little power when you switch them off, to keep a clock lit or wait for a remote. Lawrence Berkeley National Laboratory, which has studied standby power for more than 20 years, puts the total at 5 to 10 percent of home electricity use.

Any one device is small. The lab says most products now draw less than half a watt in standby, down from a typical 1 to 3 watts 20 years ago. If you leave a half-watt device plugged in for a 30-day month, it uses 0.36 kilowatt-hours, about 6 cents’ worth.

The total adds up, though. EIA data put the average U.S. home at about 899 kilowatt-hours a month in 2022, and 5 to 10 percent of that is roughly 45 to 90 kilowatt-hours, or about $8 to $16 at 18 cents.

Energy Saver’s fix is to unplug the device or flip the switch on its power strip. Start with anything that stays warm to the touch or keeps a light on after you turn it off.

Hours and season move it most

Hours are the part of the formula you control most directly. Cut the space heater from four hours a day to two and your month drops from $32.40 to $16.20. Before a space heater runs for hours, read the maker’s safety instructions and follow them.

Season moves both the hours and, in many places, the price. A heater might run only from December to February, and the EIA’s national residential average shifted over 2025, from 15.94 cents in January to 18.08 in September.

When you price a seasonal appliance, count only the months you use it, with the rate from a bill in that season.

An older fridge can cost about double

Appliance age matters most for the machines that never switch off. The same 2011 report from the Association of Home Appliance Manufacturers put a typical 1990 refrigerator at 916 kilowatt-hours a year, nearly twice the 2010 figure. At 18 cents, that’s $13.74 a month for the 1990 model against $6.93 for the 2010 one.

If you’re running a fridge from the 1990s, its EnergyGuide figure or the yearly use in its manual is worth a look.

Savings boxes don’t change the math

You’ve probably seen ads for gadgets that plug into a wall outlet and promise a smaller bill. In the spring of 2009, Texas Attorney General Greg Abbott’s office got a temporary restraining order against sales of one, a $200 plug-in cylinder sold with a claim that it trimmed household electricity use by 25 percent.

As Texas Co-op Power magazine reported that July, engineers at the University of Texas at Austin found the device could cut use in an average house by no more than 0.6 percent. Lab tests showed it was an ordinary capacitor.

In 2023, Buckinghamshire and Surrey Trading Standards in England tested plug-in boxes advertised with savings as high as 90 percent. Electricity use went up with the devices plugged in, and officers found safety faults, including access to live parts.

Your cost is watts times hours times your rate, and a box plugged into a different outlet changes none of the three.

If you want a gadget, Energy Saver points to plug-in usage monitors, which it prices at about $25 to $50 at hardware stores. They measure what a 120-volt device uses and promise nothing.

Before the next bill comes

Energy Saver’s own 1,500-watt kettle, run an hour a day, costs $100.25 a year at the July 2026 national average. Pick the one appliance in your home that makes the most heat, find the watts on its nameplate and run that one line of math with the per-kilowatt-hour rate printed on your last bill.