Every appliance in your house has a wattage rating stamped on it somewhere, usually on a sticker you have to crouch down to read. That number, your electricity rate, and how many hours the thing actually runs are the only three inputs that decide what it costs you. This section works through that arithmetic appliance by appliance.
The formula, once: watts ÷ 1,000 × hours = kWh. Multiply kWh by your rate and you have the cost. A 1,500 W space heater run for six hours uses 9 kWh. At the current US average of [hed_var key=”us_rate_cents” format=”cents”] per kWh, that is [hed_cost appliance=”space-heater” period=”day”] a day.
Why the same appliance costs wildly different amounts
Two households can run identical dryers and see a four-fold difference in what it costs them. The dryer is not the variable. The rate is. Residential electricity currently averages [hed_var key=”us_rate_cents” format=”cents”] per kWh nationally, but that average hides a spread from [hed_var key=”us_rate_low” format=”cents”] in Idaho to [hed_var key=”us_rate_high” format=”cents”] in Hawaii. Rates are also up [hed_var key=”rate_yoy_pct”] over the past year, which is why numbers you find in older articles tend to read low.
The second variable is run time, and it is the one people get wrong most often. A refrigerator is plugged in 24 hours a day but its compressor only runs a fraction of that. A space heater with a thermostat cycles too. Wattage ratings describe draw while running, not draw while switched on, and the gap between those two things is where most bad estimates come from.
Running cost by appliance
The tables below are generated from one central rate setting, so when the national average moves, every figure on every page in this section moves with it. Daily-use hours are our assumptions and yours will differ. Where an appliance has a linked page, that page explains the duty cycle in detail.
[hed_appliance_index]Work it out with your own numbers
Averages are a starting point, not an answer. If you know your rate and roughly how long something runs, these tools will get you closer than any table can:
- Electricity Cost Calculator for a single appliance.
- Whole-Home Appliance Load Calculator when you want the whole house at once.
- Time-of-Use Electricity Bill Calculator if your utility charges different rates by hour.
- Watts, Volts and Amps Calculator when the label gives you amps instead of watts.
How we get these numbers
Wattages are typical nameplate values for common residential models, with a low and high band on each appliance page because the spread within a category is often larger than the difference between categories. State rates come from EIA-derived residential averages. Nothing here is a measurement of your specific unit, and if you want that, a plug-in energy meter costs about twenty dollars and settles the argument permanently.
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