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 central air conditioner.
A central air conditioner drawing 3,500 W costs $0.57 per hour in South Carolina. Run 8 hours a day that is $4.53 daily, $136 a month and $1,654 a year, which is $231 less than the same appliance at the US average rate.
Cost by hours used per day in South Carolina
| Hours/day | Energy | Per day | Per month |
|---|---|---|---|
| 1 h | 3.50 kWh | $0.57 | $16.99 |
| 2 h | 7.00 kWh | $1.13 | $33.98 |
| 4 h | 14.00 kWh | $2.27 | $67.96 |
| 6 h | 21.00 kWh | $3.40 | $102 |
| 8 h | 28.00 kWh | $4.53 | $136 |
| 12 h | 42.00 kWh | $6.80 | $204 |
| 24 h | 84.00 kWh | $13.59 | $408 |
Cost by wattage at 16.18 cents
| Rated power | Per hour | Per day | Per month |
|---|---|---|---|
| 2,000 W | $0.32 | $2.59 | $77.66 |
| 2,500 W | $0.40 | $3.24 | $97.08 |
| 3,000 W | $0.49 | $3.88 | $116 |
| 3,500 W | $0.57 | $4.53 | $136 |
| 5,000 W | $0.81 | $6.47 | $194 |
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.
Cooling season in South Carolina
South Carolina runs one of the longest cooling seasons in the country, which means the monthly figure above applies for far more of the year than it would further north. Budget on five to seven months rather than three, and expect July and August to run well above the average because the compressor approaches continuous operation once outdoor temperatures pass the mid-nineties.
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 central air conditioner on the same schedule, in the cheapest and dearest states:
| State | Rate | Per month | Per year |
|---|---|---|---|
| Idaho | 12.35¢ | $104 | $1,262 |
| Utah | 12.96¢ | $109 | $1,325 |
| South Carolina | 16.18¢ | $136 | $1,654 |
| California | 33.25¢ | $279 | $3,398 |
| Hawaii | 52.00¢ | $437 | $5,314 |
Lowering the number in South Carolina
- Raise the thermostat before anything else. Each degree warmer cuts compressor runtime, and runtime is the entire cost. Going from 70 to 74 commonly reduces cooling energy by a fifth or more.
- Change the filter every one to three months. Restricted airflow lengthens every cycle and strains the blower.
- Seal and insulate ducts. Duct losses in an unconditioned attic routinely waste 20 to 30 percent of what the system produces.
- Run ceiling fans alongside it. A fan costs roughly a cent an hour and lets most people sit comfortably three degrees warmer.
- Shade the condenser, not the airflow. A unit in direct sun works harder, but blocking airflow around it makes things worse.
- In South Carolina, service the system before the season starts. A long cooling season leaves no slack for a unit running at reduced capacity, and refrigerant or airflow problems cost more here than in a mild climate.
Offsetting it with solar in South Carolina
This load uses about 28.00 kWh a day. Covering that would take roughly 20 standard 400 W panels at typical sun hours, an array of about 8.00 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.
A central system is a large enough load that it usually determines the size of the whole array rather than being an add-on to it. Full sizing, including battery and inverter requirements, is on the solar sizing page for this appliance.
Questions people actually ask
[hed_faq]How much does it cost to run a central air conditioner in South Carolina?About $0.57 per hour and $136 a month at 8 hours a day, using the South Carolina average rate of 16.18 cents per kWh.
How many watts does a central air conditioner use?Around 3,500 W while running, with a range of roughly 1,500 to 5,000 W depending on model and setting.
Is that expensive for South Carolina?South Carolina electricity runs 12.3 percent below the national average, so this appliance costs $231 less per year here than it would at the US average rate.
Can I lower this without replacing the appliance?Usually yes. Run time is the variable you control, and the hours table above shows exactly what each hour costs. Since South Carolina is regulated, shopping for a supplier is not an option, so usage is the lever.[/hed_faq]