The formula
Cost = watts ÷ 1000 × hours/day × days/year × rate. A 1500 W heater running 4 h/day for 6 months at $0.16/kWh: 1.5 × 4 × 180 × 0.16 = $172.80/year — more than many fridges.
Finding the power hogs
- Anything with "heat" in the name: space heaters, kettles, toasters, hair dryers (1000–2000 W) dominate — they're cheap to run briefly, brutal for hours.
- Always-on loads: fridges, routers, standby electronics draw 24/7. A 10 W standby device = 87 kWh/year ≈ $14 — small but pure waste.
- Check the label: watts are printed on the back or bottom. Kill-a-Watt style meters measure reality — labels are averages.
- AC is the king: central AC can be 3,000–5,000 W; a 1°C thermostat change cuts 5–10% of its cost.
Compare with your bill
Sum your top appliances and compare with the actual bill — the gap is usually base load (water heater, oven, mystery loads). Hunting those is where the real savings live. Pair with the LED Savings Calculator for the lighting side.