Appliance Energy Cost Calculator

Electricity bills track kilowatt-hours (kWh). Appliance draw in watts ÷ 1,000 = kilowatts; multiply by hours running per day for daily kWh; multiply by days per month and your $/kWh rate for monthly cost. A device labeled 1,500 W is 1.5 kW — but many appliances cycle or throttle, so nameplate max is an upper bound.

Defaults: 1,500 W heater × 4 hours/day × 30 days = 6 kWh/day → 180 kWh/month. At $0.15/kWh that is about $27/month. Compare to a 50 W LED bulb on 5 hours/day: roughly 7.5 kWh/month → about $1.13 at the same rate — useful for arguing thermostat versus space heater tradeoffs.

Utility bills often split energy charge, delivery, taxes, and fixed monthly fees. Use the marginal energy rate (cents per kWh for the next block of usage) rather than dividing total bill by total kWh if tiers or time-of-use rates apply — peak EV charging hours may cost double off-peak.

Common mistakes include using watts as kWh directly, assuming 24/7 draw for fridges that cycle 30% of the time, and ignoring power factor on motor loads (residential bills still meter real kWh, but measured plug meters help).

Solar panels offset grid kWh rather than replacing appliance math — production varies by season; this tool is for load-side budgeting of individual devices, not whole-home net metering.

Time-of-use rates mean the same heater costs more at 6 PM than midnight — enter the peak rate if that is when you run the load.

Limits: steady-draw model only. Does not model startup surges, seasonal HVAC duty cycles, or demand charges on commercial meters.