Home Energy Use Calculator

Most people have no idea where their electricity goes, and the intuition they do have is usually wrong. The things that feel powerful — a vacuum cleaner, a hairdryer, a microwave — draw a lot but run for minutes. The things that dominate a bill are unglamorous and run for hours or continuously: heating, cooling, water heating and refrigeration. In a typical home those four account for well over half of consumption before anything else is considered.

Breaking the bill down by category is the first useful step in reducing it, because effort should follow proportion. Replacing every bulb in a house with LEDs is worthwhile and might save five percent. Adjusting a thermostat by two degrees, or fixing a water heater that is set twenty degrees too high, can save considerably more for no cost at all. Working out which category is largest tells you where the leverage is.

Always-on loads deserve particular attention because they are invisible. A router, a set-top box, a games console left in rest mode, a second refrigerator in a garage — none of these register as an event, and all of them run eight thousand seven hundred and sixty hours a year. Eighty watts of constant background draw is seven hundred kilowatt-hours annually, which in many places is over a hundred dollars for equipment nobody is actively using.

The figures here are typical values for each appliance class rather than measurements of your specific hardware, so treat the breakdown as a map rather than a survey. A plug-in energy monitor costs very little and gives you real numbers, which frequently differ from nameplate ratings by a wide margin — particularly for anything with a compressor, which cycles rather than running steadily.