Methodology & sources

Every number on Electricity Cost Guide is either a published government statistic or the direct output of the formula below. This page documents both, so you can check our work.

The formula

cost = (watts × hours ÷ 1000) × rate

watts is the appliance's power draw while its heating/cooling/motor element is on; hours is runtime per period; rate is the residential price of electricity in dollars per kWh for the state you select. For per-load appliances (washer, dryer, dishwasher) we compute energy per cycle × cycles per week instead. For always-on appliances (fridge, freezer) we use the EnergyGuide annual kWh directly.

Constants: month = 30.42 days (365/12); year = 365 days. Sub-cent figures show 2–3 decimals; totals round to cents.

Electricity rates

Rates come from the U.S. Energy Information Administration's Electric Power Monthly, Table 5.6.A — "Average Price of Electricity to Ultimate Customers by State by Sector" (residential sector, cents per kWh). Current data period: July 2026, compared against July 2025. The U.S. average is 18.31¢. We re-pull this table with each EIA release and re-stamp every page.

EIA Table 5.6.A source data ↗

Appliance power figures

Wattage and usage figures come from:

ENERGY STAR certified-product data pages (dishwashers, dryers, dehumidifiers, refrigerators, freezers, pool pumps, televisions, ceiling fans, clothes washers)
U.S. Energy Information Administration, "Electricity use in homes" — published end-use shares and the (watts × hours) ÷ 1000 method for estimating an appliance’s energy use
EnergyGuide (yellow label) annual-kWh figures where a model-specific number matters
U.S. DOE Alternative Fuels Data Center for EV charging efficiency

Where appliance draw varies by model and setting, we present the published range and let the calculator sliders move within it. We do not publish unsourced statistics, "average savings" claims, or modeled numbers dressed as measurements.

What these numbers are — and aren't

What they are

Planning estimates using official state-average rates and manufacturer/government power figures. They're excellent for comparing appliances against each other, budgeting a new purchase's running cost, or understanding what changed on your bill.

What they aren't

Not billing advice. Your utility's exact rate, tiers, time-of-use windows, demand charges, and your specific appliance model all shift real costs. The calculators apply EIA state averages, so compare your bill's "price to compare" with that average to gauge the difference. For exact appliance draw, a $20 plug-in power meter beats every estimate.

A worked example

Take a 1,500 W portable space heater in Louisiana, where the EIA residential average is 12.72¢/kWh. Running it 6 hours a day for a 30.42-day month:

1.Energy = 1,500 W ÷ 1,000 × 6 h × 30.42 days = 273.8 kWh a month
2.Cost = 273.8 kWh × 12.72¢ ÷ 100 = $34.83 a month
3.Per hour = 1.5 kW × 12.72¢ = $0.191

The same heater in Hawaii costs $131.42 a month — $96.60 more, with no change to how the appliance is used. That gap is the entire reason this site exists, and it is why every calculator lets you pick a state.

Corrections

Found a number that looks off? The full source list is on every calculator page. Write to hello@electricitycostguide.com and we'll re-verify against the source.

Rate data: EIA Electric Power Monthly Table 5.6.A, July 2026, retrieved September 2026. Electricity Cost Guide is an independent informational site; it is not affiliated with the EIA, DOE, or ENERGY STAR.