Who we are
Our day job is turning tariffs into invoices: time-of-use periods, tiered blocks, seasonal prices, fixed charges, riders and the edge cases that make a real bill differ from the brochure. HomeWattCost applies that same machinery to the question households actually ask: what will this cost me?
How we check the numbers
We read each residential plan from the utility’s own tariff and rider sheets, all charges included, and date it. Right now 142 of 144 plans across 80 utilities in 50 states and the District of Columbia have been checked line by line against those documents; the rest come from the OpenEI Utility Rate Database and say so on the page. Each plan links to its sources and shows when it was last checked, and plans are re-checked whenever a fuel charge, rider or rate case changes them. State prices, gas and gasoline come from the U.S. Energy Information Administration; EV efficiency from the EPA; home load and solar profiles from NREL’s ResStock and PVWatts. The methodology explains every formula and default.
Why tariffs, not averages
Most “cost to charge” and “electricity cost” pages multiply by a state or national average. That hides the two things that change your bill most: the rate plan you are on and the hour you use power. HomeWattCost models each utility’s plans period by period, so the answer depends on your utility, your plan and your habits.
Independence
HomeWattCost does not sell electricity, solar panels or heat pumps, and does not pass your details to installers or retailers. It is free and supported by display advertising, which never sits between a calculator’s inputs and its result.
Corrections
Found a tariff that has changed, or a number that looks wrong? Corrections are the most valuable message we get: tell us the utility, the plan and, if you can, a link to the new tariff sheet. Write to contact@homewattcost.com.