Running cost comes down to wattage, hours and your rate. In South Dakota the rate is 15.73 cents per kWh, which is 14.7 percent below the national average. Here is what that means for a electric water heater.
A electric water heater drawing 4,000 W costs $0.63 per hour in South Dakota. Run 3 hours a day that is $1.89 daily, $56.63 a month and $689 a year, which is $119 less than the same appliance at the US average rate.
Electric water heater cost at South Dakota 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 Dakota
| Hours/day | Energy | Per day | Per month |
|---|---|---|---|
| 1 h | 4.00 kWh | $0.63 | $18.88 |
| 2 h | 8.00 kWh | $1.26 | $37.75 |
| 4 h | 16.00 kWh | $2.52 | $75.50 |
| 6 h | 24.00 kWh | $3.78 | $113 |
| 8 h | 32.00 kWh | $5.03 | $151 |
| 12 h | 48.00 kWh | $7.55 | $227 |
| 24 h | 96.00 kWh | $15.10 | $453 |
Cost by wattage at 15.73 cents
| Rated power | Per hour | Per day | Per month |
|---|---|---|---|
| 3,000 W | $0.47 | $1.42 | $42.47 |
| 3,800 W | $0.60 | $1.79 | $53.80 |
| 4,500 W | $0.71 | $2.12 | $63.71 |
| 5,000 W | $0.79 | $2.36 | $70.79 |
| 5,500 W | $0.87 | $2.60 | $77.86 |
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 Dakota
Incoming groundwater temperature sets how hard the element works, and it is colder in winter everywhere. South Dakota sees a wide seasonal swing, so winter water heating costs meaningfully more than the annual average suggests. A heat pump water heater cuts consumption to roughly a third and works particularly well in a warm garage.
Why South Dakota pays what it does
South Dakota 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 15.73 cents, South Dakota ranks 21 of 51 from cheapest to most expensive. The Midwest regional average is 16.55 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 Dakota | 15.73¢ | $56.63 | $689 |
| California | 33.25¢ | $120 | $1,456 |
| Hawaii | 52.00¢ | $187 | $2,278 |
Lowering the number in South Dakota
- 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.
- In South Dakota, air sealing pays back faster than equipment upgrades. A long heating season multiplies every draft, and sealing is cheap compared with replacing hardware.
Offsetting it with solar in South Dakota
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 15.73 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.