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Appliance Energy Costs: What a Watt Actually Costs
Convert appliance wattage into real electricity costs, compare old and new appliances, and find the biggest savings in your home.
Written by James — Founder & Builder, BoringToolsKit · Published 2026 · Planning information, not professional advice.
From watts to dollars
An appliance's power draw is measured in watts, and electricity is billed in kilowatt-hours: 1,000 watts running for 1 hour is 1 kWh. A 100-watt bulb left on 10 hours uses 1 kWh per day. At $0.15 per kWh, that is $0.15 daily and about $55 per year for a single bulb.
The big hitters in most homes
Heating and cooling dominate, followed by water heating, laundry, and refrigeration. A space heater at 1,500 watts running 8 hours daily costs about $1.80 per day at $0.15/kWh — over $650 per year. A modern refrigerator runs around 150 watts but cycles, costing roughly $65 per year. The calculator shows both continuous and cycled loads.
Efficiency labels translate to dollars
ENERGY STAR appliances quote annual kWh, which converts directly to annual cost at your rate. Replacing a 15-year-old fridge that uses 700 kWh with a 350 kWh model saves about 350 kWh per year — $52 at $0.15/kWh, roughly the price of a new budget model every decade of use.
Lights: the cheapest win
Swapping a 60-watt incandescent for a 9-watt LED cuts the draw by 85 percent. At 3 hours daily, one bulb saves about 51 watts × 3 hours × 365 days ≈ 56 kWh per year — about $8.40 per bulb per year at $0.15/kWh. Across a whole house, lighting swaps pay for themselves quickly.
Use the tool to rank your savings
Enter each appliance's wattage, hours, and your rate to see daily, monthly, and yearly cost. Rank the list to find the biggest levers, then compare the cost of running an old appliance against the payback of replacing it. The math is local and private — nothing is uploaded.
Heating and cooling dominate
HVAC is roughly half of a typical home's energy use. A 3,500-watt central AC running 6 hours daily at $0.15/kWh costs about $3.15 per day — over $940 for a three-month cooling season. Raising the thermostat two degrees or servicing the unit usually pays more than any appliance swap.
Phantom loads add up
Electronics in standby still draw power: a game console, cable box, and charger together can pull 30-60 watts around the clock, costing $40-80 per year. Smart power strips cut the draw when devices are off. Small, constant loads are invisible on a bill but real in the yearly total.