Running cost comes down to wattage, hours and your rate. In South Carolina the rate is 16.18 cents per kWh, which is 12.3 percent below the national average. Here is what that means for a electric water heater.
A electric water heater drawing 4,000 W costs $0.65 per hour in South Carolina. Run 3 hours a day that is $1.94 daily, $58.25 a month and $709 a year, which is $98.99 less than the same appliance at the US average rate.
Electric water heater cost at South Carolina rates
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Planning estimate. The rate box is prefilled with a regional average; the figure on your own bill is the one that matters. Power is draw while running, not while switched on.
Cost by hours used per day in South Carolina
| Hours/day | Energy | Per day | Per month |
|---|---|---|---|
| 1 h | 4.00 kWh | $0.65 | $19.42 |
| 2 h | 8.00 kWh | $1.29 | $38.83 |
| 4 h | 16.00 kWh | $2.59 | $77.66 |
| 6 h | 24.00 kWh | $3.88 | $116 |
| 8 h | 32.00 kWh | $5.18 | $155 |
| 12 h | 48.00 kWh | $7.77 | $233 |
| 24 h | 96.00 kWh | $15.53 | $466 |
Cost by wattage at 16.18 cents
| Rated power | Per hour | Per day | Per month |
|---|---|---|---|
| 3,000 W | $0.49 | $1.46 | $43.69 |
| 3,800 W | $0.61 | $1.84 | $55.34 |
| 4,500 W | $0.73 | $2.18 | $65.53 |
| 5,000 W | $0.81 | $2.43 | $72.81 |
| 5,500 W | $0.89 | $2.67 | $80.09 |
Find the row matching the nameplate on your own unit. Within a single appliance category the spread is often wider than the difference between categories, so the label is worth reading.
Water heating in South Carolina
Incoming groundwater temperature sets how hard the element works, and it is colder in winter everywhere. In South Carolina the seasonal swing is smaller, which keeps water heating cost relatively steady through the year. A heat pump water heater cuts consumption to roughly a third and works particularly well in a warm garage.
Why South Carolina pays what it does
South Carolina is a regulated market, so your utility is the only supplier and the rate is set through the state commission rather than by competition. Pricing tends to be steadier than in deregulated states, and there is no switching decision available. The levers are all on your side of the meter.
At 16.18 cents, South Carolina ranks 25 of 51 from cheapest to most expensive. The Southeast regional average is 16.16 cents. Roughly half of any residential bill is transmission and distribution rather than generation, which is why rates keep climbing even when fuel prices fall.
How this compares across the country
The same electric water heater on the same schedule, in the cheapest and dearest states:
| State | Rate | Per month | Per year |
|---|---|---|---|
| Idaho | 12.35¢ | $44.46 | $541 |
| Utah | 12.96¢ | $46.66 | $568 |
| South Carolina | 16.18¢ | $58.25 | $709 |
| California | 33.25¢ | $120 | $1,456 |
| Hawaii | 52.00¢ | $187 | $2,278 |
Lowering the number in South Carolina
- Set the thermostat to 120 degrees. Many ship at 140. Every 10 degrees cuts standby loss by around 4 percent.
- Insulate the first six feet of hot and cold pipe. Cheap, and it stops heat walking out through the plumbing.
- Fix dripping hot taps. A hot tap dripping once a second heats water that goes straight down the drain.
- Flush sediment annually. Sediment insulates the lower element from the water, so it runs longer.
- Consider a heat pump water heater. Roughly a third of the energy for the same hot water.
Offsetting it with solar in South Carolina
This load uses about 12.00 kWh a day. Covering that would take roughly 9 standard 400 W panels at typical sun hours, an array of about 3.60 kW. Because it offsets electricity worth 16.18 cents rather than the national 18.44 cents, the same array is worth less here than the national payback figures suggest.
Water heating is the single best use of surplus solar, because the tank is a battery that stores heat instead of electrons. Diverter controllers exist specifically for this. Full sizing, including battery and inverter requirements, is on the solar sizing page for this appliance.