Electricity cost
Energy in kilowatt-hours equals watts × hours ÷ 1,000. Operating cost equals kWh × the entered electricity rate. Daily, monthly, and annual values use the schedule entered by the visitor; a full average year uses 365 days.
Comparisons
EV charging includes a user-selected charging-loss factor. Heat-pump and gas comparisons convert the same delivered-heat requirement using COP and furnace efficiency. Battery runtime reduces nameplate capacity for reserve and inverter losses. Time-of-use calculations split monthly kWh between entered peak and off-peak shares.
Inputs and defaults
Defaults are illustrative planning assumptions—not measurements, live quotes, or local guarantees. Visitors can replace them with utility rates, labels, manuals, interval data, or meter readings.
Rounding
Calculations retain more precision internally than the interface displays. Currency generally displays to cents, energy to two decimals, and runtime to a practical precision. Rounding can create small differences when displayed components are recombined.
Limits
Utility bills may include fixed fees, taxes, delivery charges, tiers, minimums, demand charges, credits, or rate structures not modeled. Climate, equipment efficiency, installation, fuel prices, utility policies, and behavior can materially change results.