Why Is My Electric Bill So High All of a Sudden? How to Find the Cause
A bill is two numbers multiplied: how many kilowatt-hours you used and what each one cost. Work out which of the two moved, and the list of suspects gets short.
Quick answer
First compare kilowatt-hours with the same month last year, not dollars. If the kilowatt-hours are about the same, the price or the length of the billing period changed. If they jumped, look for heat: a space heater, electric water heating, a heat pump on backup heat, a dehumidifier or extra dryer loads. One 1,500-watt heater run 8 hours a day adds about 360 kilowatt-hours a month.
- Difficulty
- Easy DIY
- Compare first
- Kilowatt-hours against the same month last year
- Average U.S. home
- About 899 kWh a month (EIA, 2022)
- Biggest electric uses
- Air conditioning, space heating, water heating (EIA)
- Rate used in this guide
- 18.31¢ per kWh, U.S. average, July 2026 (EIA)
On this page
An electric bill is the number of kilowatt-hours (kWh) you used multiplied by the price of each one, plus fixed charges. When the total jumps, one of those moved. Finding out which takes two minutes with this month’s bill and the bill for the same month last year.
Step 1: read the bill before you blame an appliance
- Compare kilowatt-hours, not dollars.Safe check
Find “kWh used” on both bills. Compare with the same month a year ago, because use follows the weather. The Energy Information Administration notes that the shares of home electricity use change from year to year for that reason.
- Count the days.Safe check
Bills print the start and end of the billing period. A longer period means a bigger bill with no change in your daily use. Divide kWh by days to compare fairly.
- Look for the word “estimated.”Safe check
If the utility estimated a reading, a later bill corrects it, and that correction can land all at once.
- Work out the price per kWh.Safe check
Divide the energy charges by the kWh. If that figure rose, the cause is the rate or your plan, not your home. The U.S. average residential price in July 2026 was 18.31 cents per kWh.
If the kilowatt-hours per day are close to last year’s, stop here: your use did not change, and the utility or your supplier is the place to ask. If they jumped, go on.
Step 2: find the load
Electricity turned into heat is where large, sudden increases come from. The EIA lists air conditioning, space heating and water heating as the three largest uses of electricity in U.S. homes.
This table shows what common changes add in a 30-day month at the U.S. average price of 18.31 cents per kWh. Wattages come from the nameplate figures and ranges published by Virginia Cooperative Extension (the dryer’s 3,000 watts is a value inside its 1,800 to 5,000 watt range); cost is watts × hours ÷ 1,000 × price.
| What changed | Power | Extra use | Added kWh a month | Added cost a month |
|---|---|---|---|---|
| Portable heater on high | 1,500 W | 4 hours a day | 180 | $32.96 |
| Portable heater on high | 1,500 W | 8 hours a day | 360 | $65.92 |
| Electric water heater working harder | 4,500 W | 1 extra hour of heating a day | 135 | $24.72 |
| Dehumidifier | 785 W | 8 hours a day | 188 | $34.50 |
| Furnace fan left on | 750 W | 12 extra hours a day | 270 | $49.44 |
| Electric dryer | 3,000 W | 4 extra one-hour loads a week | 51 | $9.42 |
| Electric blanket | 100 W | 8 hours a night | 24 | $4.39 |
For comparison, the average U.S. home buys about 899 kWh a month. One heater on for 8 hours a day adds 40 percent to that. A blanket, a TV or a phone charger cannot explain a large jump; a heater, a water heater or a heating system can.
Nameplate wattage is the most an appliance draws. A dehumidifier or furnace fan often draws less, and a dryer listed between 1,800 and 5,000 watts varies with the model, so treat the table as an upper guide. Put your own numbers in the appliance energy cost calculator.
Where to look, by season
In the heating season
- Portable heaters, including ones in a garage, basement or pet area that stay on. See what a space heater costs to run.
- A heat pump leaning on its backup heat. If the thermostat shows AUX or EM heat for long stretches, or the outdoor unit is iced over, read a heat pump freezing up.
- Electric water heating. Hot water that runs out sooner than it used to, along with a higher bill, points to the water heater: see a water heater that is not heating.
- The thermostat fan set to On instead of Auto, which runs the blower all day.
All year
- A second refrigerator or a separate freezer. The EIA puts the average cost of running a second refrigerator at about $66 a year in 2020 and a separate freezer at $74. See how much electricity a refrigerator uses.
- More laundry, or a dryer that needs two cycles to dry a load. See how much electricity a dryer uses.
- Something new: a guest, a home office, an aquarium, a dehumidifier, an electric vehicle.
Step 3: confirm it
Pick the suspect, change one thing for a full billing period, and compare kWh per day again. Many utilities show daily or hourly use in their online account, which gives the answer in days instead of a month.
Do not open the electrical panel or the meter to investigate. Everything in this guide is done from the bill, the thermostat and the appliance’s own controls. If you suspect a wiring fault, because a breaker is warm, buzzing or tripping, call an electrician.
If you heat water with an electric tankless heater, what a tankless water heater costs to run shows the cost per gallon and per month.
For what a heat pump costs per hour, and how much more its backup heat costs, see what a heat pump costs to run.
Frequently asked questions
What uses the most electricity in a house?
The U.S. Energy Information Administration lists the three largest uses of electricity in homes in 2020 as air conditioning at 19 percent, space heating at 12 percent and water heating at 12 percent, followed by lighting and refrigerators. The shares change from year to year with the weather.
How much electricity does a normal house use in a month?
The EIA reports that the average U.S. residential customer bought 10,791 kilowatt-hours in 2022, about 899 a month. State averages ranged from 6,178 kilowatt-hours a year in Hawaii to 14,774 in Louisiana, so compare your bill with your own past bills first.
Can one appliance double my electric bill?
A heating appliance can come close. A 1,500-watt space heater running 8 hours a day uses about 360 kilowatt-hours a month, which is 40 percent of what the average U.S. home buys in a month. Two heaters, or one running around the clock, can do it.
Will electric bills be higher this winter?
In its October 2026 outlook the EIA expects households that heat mainly with electricity to spend more this winter than last, while households that heat with natural gas or propane are expected to spend less.
Could the meter be wrong?
Rule out the simpler explanations first. Check whether the bill says the reading was estimated, and whether the billing period was longer than usual. If the kilowatt-hours still make no sense after you have gone through the loads in your home, ask the utility to check the meter.
Sources
- Electricity use in homes U.S. Energy Information Administration
- How much electricity does an American home use? U.S. Energy Information Administration
- Electric Power Monthly, Table 5.6.A: Average Price of Electricity to Ultimate Customers U.S. Energy Information Administration
- EIA expects a mixed picture for winter fuel costs this year (October 6, 2026) U.S. Energy Information Administration
- Estimating Appliance and Home Electronic Energy Use (publication 2901-9014) Virginia Cooperative Extension, Virginia Tech
First published October 13, 2026. Last reviewed October 13, 2026. Spot an error? Tell us and we will check it against the source.