Running cost comes down to wattage, hours and your rate. In District of Columbia the rate is 25.40 cents per kWh, which is 37.7 percent above the national average. Here is what that means for a electric water heater.
A electric water heater drawing 4,000 W costs $1.02 per hour in District of Columbia. Run 3 hours a day that is $3.05 daily, $91.44 a month and $1,113 a year, which is $305 more than the same appliance at the US average rate.
Electric water heater cost at District of Columbia 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 District of Columbia
| Hours/day | Energy | Per day | Per month |
|---|---|---|---|
| 1 h | 4.00 kWh | $1.02 | $30.48 |
| 2 h | 8.00 kWh | $2.03 | $60.96 |
| 4 h | 16.00 kWh | $4.06 | $122 |
| 6 h | 24.00 kWh | $6.10 | $183 |
| 8 h | 32.00 kWh | $8.13 | $244 |
| 12 h | 48.00 kWh | $12.19 | $366 |
| 24 h | 96.00 kWh | $24.38 | $732 |
Cost by wattage at 25.40 cents
| Rated power | Per hour | Per day | Per month |
|---|---|---|---|
| 3,000 W | $0.76 | $2.29 | $68.58 |
| 3,800 W | $0.97 | $2.90 | $86.87 |
| 4,500 W | $1.14 | $3.43 | $103 |
| 5,000 W | $1.27 | $3.81 | $114 |
| 5,500 W | $1.40 | $4.19 | $126 |
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 District of Columbia
Incoming groundwater temperature sets how hard the element works, and it is colder in winter everywhere. In District of Columbia 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 District of Columbia pays what it does
District of Columbia has a competitive retail electricity market, so the rate used here blends households on the utility default with households on shopped supply plans. If you have never switched supplier you are probably on the default, which is usually the more expensive side of that blend. Only the generation portion of your bill changes when you switch; delivery and outage response do not.
At 25.40 cents, District of Columbia ranks 42 of 51 from cheapest to most expensive. The Northeast regional average is 25.91 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 |
| District of Columbia | 25.40¢ | $91.44 | $1,113 |
| California | 33.25¢ | $120 | $1,456 |
| Hawaii | 52.00¢ | $187 | $2,278 |
Lowering the number in District of Columbia
- 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 District of Columbia
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 25.40 cents rather than the national 18.44 cents, the same array is worth more 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.