Electricity Cost Calculator

Electricity cost = Power (watts) ÷ 1000 × Hours used × Rate ($/kWh). Example: a 1500W space heater running 8 hours/day at $0.15/kWh costs 1500 ÷ 1000 × 8 × 0.15 = $1.80/day. Monthly (30 days) = $54. Key concept: kWh (kilowatt-hour) is the unit utilities bill you for. 1 kWh = 1,000 watts running for 1 hour = 100 watts running for 10 hours. Your electric bill rate is usually shown as cents per kWh. US average: ~$0.16/kWh (varies widely by state — Hawaii ~$0.40, Louisiana ~$0.11).

Typical US household electricity breakdown: HVAC (heating/cooling): 45–50% of usage. Water heating: 14–18%. Appliances (refrigerator, washer/dryer, dishwasher): 13%. Lighting: 9%. Electronics (TV, computers, gaming): 6%. Other (standby loads, small appliances): remainder. Biggest energy hogs per hour: Electric furnace: 10,000–25,000W. Central AC: 2,000–5,000W. Electric water heater: 4,000–5,000W. Electric dryer: 4,000–6,000W. Space heater: 750–1,500W. Refrigerator: 100–800W (runs intermittently).

Phantom load (also called standby power or vampire power) is electricity consumed by devices when they're turned off but still plugged in. Common standby loads: TV: 1–5W. Game console: 1–15W. Phone charger (no phone): 0.1–0.5W. Microwave (clock/display): 3–5W. Cable box: 10–20W (highest, often comparable to when in use!). Computer (sleep mode): 1–6W. Annual cost estimate: 1W of constant standby = ~8.76 kWh/year. At $0.15/kWh = ~$1.31/year per watt. A home with 50W average standby = ~$65/year wasted. Fix: smart power strips, unplugging devices, smart plugs with scheduling.

Your electric bill shows: Total kWh used (e.g., 850 kWh). Total amount charged (e.g., $136). Effective rate = $136 ÷ 850 = $0.16/kWh. But rates have tiers: First 500 kWh at $0.11, next 500 kWh at $0.18, etc. Your bill may include: Energy charge (the base rate per kWh). Distribution/delivery charge (flat or per kWh). Fixed monthly fee (whether you use electricity or not). Taxes and fees. For this calculator, use your effective rate (total bill ÷ total kWh) for the most accurate results. Or use the energy charge alone to isolate just the usage cost.

High-impact changes: Switch to LED bulbs (75% less energy than incandescent). Install a programmable/smart thermostat (10–15% HVAC savings). Air-seal and insulate (up to 30% savings). Replace old appliances with Energy Star models. Run dishwasher/washer in off-peak hours if time-of-use pricing applies. Medium-impact: Unplug devices or use smart power strips. Wash clothes in cold water. Clean dryer lint trap and vent (improves efficiency). Adjust fridge temperature (3°C / 37°F fridge; -18°C / 0°F freezer). Low-impact but easy: Turn off lights when leaving rooms. Lower water heater to 49°C (120°F). Use power-saving mode on computers.