RunCost Lab

METHODOLOGY

Visible assumptions. Reproducible math.

RunCost Lab separates appliance inputs, electricity-rate context and bill-specific charges.

Core formula

Cost = kW × effective runtime × electricity rate. Watts are divided by 1,000. Effective runtime is hours switched on multiplied by duty cycle. Monthly estimates use 30 days; annual estimates use 365.

State-rate data

State comparisons use the residential column in U.S. EIA Electric Power Monthly Table 5.6.A for May 2026. EIA describes these as average prices, calculated from revenue and sales. Values are preliminary estimates and are not utility tariffs.

Data updatedEIA residential prices · May 2026View Table 5.6.A

Limits

Estimates exclude taxes, fixed fees, tiered pricing, demand charges, seasonal changes and loads not entered. Direct measurement, EnergyGuide annual kWh and the effective rate on your utility bill are stronger inputs than presets.

Update policy

Data displays its month and source. When EIA publishes a newer table, the dataset, summary, charts and this record should move together and be checked against the official release.