How this list was built
Each appliance is ranked by a realistic monthly cost using typical wattages, typical hours of use, and the U.S. average residential rate of 18.34¢ per kWh (June 2026, EIA). "Typical" matters: a hot tub in Minnesota and a hot tub in Florida are different appliances, and a 20-year-old air conditioner is not the one in the table. Where the range is wide, it is noted.
The ranking is meant to answer one question: where should you look first? It is not a reason to feel bad about the air conditioner. It is a reason to stop unplugging the toaster.
The ranking
| # | Appliance | Typical draw | Typical use | Cost / month |
|---|---|---|---|---|
| 1 | Central air conditioning | 3,500 W avg | 8 h × 7 d/wk | $156 |
| 2 | Electric water heater | 4,500 W | 3 h × 7 d/wk | $75.10 |
| 3 | EV home charging | 7,200 W | 1.5 h × 7 d/wk | $60.08 |
| 4 | Space heater, 8 hours a day | 1,500 W | 8 h × 7 d/wk | $66.76 |
| 5 | Hot tub | 400 W avg | 24 h × 7 d/wk | $53.41 |
| 6 | Pool pump, single speed | 1,500 W | 8 h × 7 d/wk | $66.76 |
| 7 | Electric clothes dryer | 3,000 W | 1 h × 4 d/wk | $9.54 |
| 8 | Old or garage refrigerator | 150 W avg | 24 h × 7 d/wk | $20.03 |
| 9 | Dehumidifier | 500 W avg | 10 h × 7 d/wk | $27.82 |
| 10 | Gaming PC | 450 W | 4 h × 7 d/wk | $10.01 |
Not on the list but worth mentioning: an electric furnace or resistance baseboard heating for a whole house can dwarf everything above it, at 1,500 to 3,000 kWh a month in a cold climate. If that is your heating, a heat pump is the single largest saving available to any household. And an electric tankless water heater, at up to 18,000 W, lands roughly where the tank heater does once you account for its shorter run time.
1. Central air conditioning
About $156 a month (849 kWh) at 3,500 W average, 8 hours a day, 7 days a week. Compressor plus blower while running. Enter the hours the system actually runs, not the hours it is switched on.
The fix: Raise the setpoint. Each degree above 75°F saves about 3% of cooling energy; 78°F when home and 85°F when out is the standard advice. Change filters, close blinds on the sunny side, and seal attic ducts. If the unit is over 15 years old, a modern 16+ SEER replacement uses about 40% less.
2. Electric water heater
About $75.10 a month (410 kWh) at 4,500 W, 3 hours a day, 7 days a week. Element draw. About 3 hours of heating per day for a family of four.
The fix: Set it to 120°F, insulate the first six feet of hot pipe, and fix drips. The bigger move is a heat pump water heater, which uses about a third of the electricity of a resistance tank; with utility rebates the payback is often three to five years at the national average rate.
3. EV home charging
About $60.08 a month (328 kWh) at 7,200 W, 1.5 hours a day, 7 days a week. 1.5 hours a day is roughly 35 to 40 miles of range.
The fix: Get on an EV or time-of-use rate and charge overnight. Off-peak rates of 8 to 12¢ per kWh cut the cost by half or more compared with a flat rate. See the EV charging calculator for your own numbers.
4. Space heater, 8 hours a day
About $66.76 a month (364 kWh) at 1,500 W, 8 hours a day, 7 days a week. Full-power draw on the high setting. Most plug-in heaters top out at 1,500 W.
The fix: Use the thermostat so it cycles, close the door, and turn the central heating down while it runs. If it is running to make one person comfortable, a 100 W heated blanket or throw does the same job for a fifteenth of the cost.
5. Hot tub
About $53.41 a month (291 kWh) at 400 W average, 24 hours a day, 7 days a week. Averaged. The 4 kW heater only runs part of the time; cold climates push this higher.
The fix: Keep a good insulated cover on it whenever it is not in use; heat loss through the water surface is where most of the energy goes. Lower the setpoint to 100°F between uses, and in cold climates consider a thermal blanket under the hard cover.
6. Pool pump, single speed
About $66.76 a month (364 kWh) at 1,500 W, 8 hours a day, 7 days a week.
The fix: Replace it with a variable-speed pump. Running slower for longer moves the same water for a quarter of the energy, and many utilities offer rebates. Until then, cut the run time: most pools need 6 to 8 hours, not 12.
7. Electric clothes dryer
About $9.54 a month (52 kWh) at 3,000 W, 1 hours a day, 4 days a week. A full load is about 3 kWh. Set days to loads per week.
The fix: Clean the lint filter every load and the vent yearly; a blocked vent doubles drying time. Use the moisture sensor setting rather than a timer. A heat pump dryer uses about a third of the energy, and a drying rack uses none.
8. Old or garage refrigerator
About $20.03 a month (109 kWh) at 150 W average, 24 hours a day, 7 days a week. Old or garage fridges routinely use 2 to 3 times more than a new one.
The fix: If it is a second fridge that is mostly empty, unplug it. If it is the main fridge and it is more than 15 years old, replacing it typically saves 700 to 900 kWh a year and pays back in four to six years; many utilities will haul the old one away for a rebate.
9. Dehumidifier
About $27.82 a month (152 kWh) at 500 W average, 10 hours a day, 7 days a week.
The fix: Set the humidistat to 50% rather than running continuously, empty it into a drain instead of a bucket so it never stops for a full tank, and fix the source of the moisture where you can. Newer ENERGY STAR units remove about 30% more water per kWh.
10. Gaming PC
About $10.01 a month (55 kWh) at 450 W, 4 hours a day, 7 days a week.
The fix: Enable a frame-rate cap so the GPU is not running flat out on menus, set the PC to sleep after 15 minutes idle, and hibernate overnight rather than leaving it on. A high-end PC at idle can still draw 100 W.
What did not make the list
Lighting, cooking, laundry washing, televisions, computers used for work, phone chargers and almost every kitchen gadget. Together they typically account for 15 to 20% of a household's electricity, and no single one of them is worth more than a few dollars a month. The wattage chart has the figures if you want to check one, and the phantom load guide covers the always-on devices.
The practical takeaway: pick the top two or three items on this list that apply to your home and work on those. A thermostat schedule, a water heater at 120°F and an overnight EV charging schedule will beat a hundred small habits, and the calculator will show you exactly what each change is worth at your rate.