Find out how much your air conditioner costs to run per hour. Enter AC wattage and electricity rate for instant cost estimates.
Air conditioning is often the single largest electricity expense in warm-climate households. A window unit might draw 500–1,500 watts, while a central AC system can draw 2,000–5,000 watts when running. Knowing the cost per hour helps you make informed decisions about thermostat settings, runtime, and efficiency upgrades.
The actual running cost depends on the unit's wattage (or tonnage converted to watts), your electricity rate, and how many hours the compressor runs each day. A 3-ton central AC unit typically draws about 3,500 watts and may run 8‒12 hours on a hot day, costing $4–$6 daily.
This calculator gives you the per-hour cost of running your AC based on its wattage and your rate. Use it to evaluate whether raising the thermostat a few degrees, using ceiling fans, or upgrading to a higher SEER unit makes financial sense for your situation.
Integrating this calculation into regular energy reviews ensures that conservation strategies are grounded in measured data rather than assumptions about building performance and usage patterns.
Air conditioning can account for 30–70% of your summer electricity bill. Knowing the exact per-hour cost helps you make smart decisions about usage, thermostat settings, and equipment upgrades. This quantitative approach replaces rough estimates with precise figures, enabling facility managers to identify the most cost-effective opportunities for reducing energy consumption.
Cost per Hour ($) = Watts / 1,000 × Rate ($/kWh)
Result: $0.49/hour
A 3,500W central AC costs 3,500 / 1,000 × $0.14 = $0.49 per hour to run. At 10 hours/day, that's $4.90/day or about $147/month during peak summer.
Window units: 500–1,500W. Portable AC: 900–1,400W. Ductless mini-split: 600–2,000W. Central AC: 2,000–5,000W. The most efficient option per BTU of cooling is typically a ductless mini-split, followed by central AC, then window and portable units.
Beyond raising the thermostat, consider adding attic insulation, sealing duct leaks, shading south-facing windows, and ensuring your AC is properly sized for your home. An oversized AC short-cycles (wastes energy), while an undersized unit runs constantly without reaching the set temperature.
If your AC is 10–15+ years old, it likely has a SEER rating of 10–13. Replacing it with a SEER 16–20 unit can reduce cooling costs by 30–50%. Factor in utility rebates and tax credits that may be available for high-efficiency equipment.
A central AC system typically uses 2,000–5,000 watts depending on the tonnage. A 2-ton unit draws about 2,400W, a 3-ton about 3,500W, and a 5-ton about 5,000W. The nameplate on your outdoor unit lists the exact watts or amps.
On a hot day (95°F+), a properly sized AC may run 12–16 hours. On a mild day (80–85°F), it might run 4–8 hours. Well-insulated homes in moderate climates may only need 2–4 hours. Short-cycling (frequent on/off) indicates a sizing or maintenance issue.
A window unit uses less total energy (500–1,500W) but only cools one room. For cooling an entire home, central AC is more efficient overall. For cooling a single room, a window unit or mini-split is usually cheaper than whole-house central air.
SEER 14–16 is standard for new units. SEER 18–22 is high-efficiency and can reduce cooling costs by 20–40% compared to SEER 14. The higher upfront cost is offset by lower operating costs, especially in hot climates.
Yes, dramatically. A ceiling fan uses 15–75 watts compared to 2,000–5,000 watts for central AC. Fans don't cool the air, but the wind-chill effect lets you set the thermostat 4–6 degrees higher while feeling comfortable.
A rough estimate is 1 ton of cooling = 1,000–1,200 watts of electrical input for a SEER 14 unit. So a 3-ton unit draws about 3,000–3,600 watts. Higher SEER units draw fewer watts per ton because they are more efficient.