How the appliance electricity calculator works
The formula that runs your bill
kWh = watts × hours ÷ 1000. Cost = kWh × rate. A 1500 W space heater running 1 hour at $0.15/kWh costs 22.5¢ — run it 8 hours daily for a winter and the season costs ~$80. The calculator extends the arithmetic to day, month, and year, with a quantity field for fleets (bulbs, monitors, the server rack in the closet).
Finding honest inputs
- Watts: nameplate for resistive devices (heaters, toasters run at rating); average draw for cycling ones — a fridge rated 300 W averages ~100–150 W as the compressor cycles.
- Hours: actual use; standby devices count 24 h at their idle draw (1–5 W typical for anything with a remote).
- Rate: bill ÷ kWh — the true rate includes delivery and taxes.
The suspects, ranked
- Heating and cooling (HVAC, water heater, dryer, sauna) — resistive heat is the king of kWh.
- Always-on electronics — the 10 W that never sleeps costs $13/yr each; a house has a dozen.
- Kitchen heat appliances — short but brutal (toaster oven, kettle).
- Everything else — LED lighting and modern electronics are rounding errors.