Household · official-source review · reviewed 2026-10-10
The water heater runs whether you notice it or not, and the bill hides the reason.
Turn daily hot-water use, a temperature rise, and an electricity rate into an annual and monthly cost.
Households comparing water-heater settings, sizes, or habits.
Use the source document or official route that applies to your situation. This guide does not contact another person or verify external information.
Estimate the hot gallons your household uses in a day. Showers and laundry carry most of it.
Subtract your inlet temperature from your heater setting. A rise of 70 degrees is common.
Read the price per kilowatt-hour from a recent bill. Use the full delivered rate, not the base charge alone.
Multiply gallons by 365, by the rise, and by 0.0024. That is the kilowatt-hours per year.
Multiply the kilowatt-hours by your rate. Divide by 12 to see the monthly figure.
You heat 40 gallons a day by 70 degrees at 15 cents a kilowatt-hour. That is 2,452.8 kilowatt-hours, $367.92 a year, and $30.66 a month.
Use your own source and details. The example is not a record about a real person or organization.
U.S. Department of Energy, Energy Saver · reviewed 2026-10-10
What this source supports: Water heaters lose capacity over time; the Department of Energy describes repair and replacement considerations by fuel type and size.
Source limit: Parts, labor, and code requirements vary by region and by unit. Obtain local quotes before you decide.
These sources support the statements above. They do not show that every person needs this guide. They do not show a specific result.
This guide estimates cost from an arithmetic model. It does not read your meter or measure your heater's efficiency.
Parts, labor, and code requirements vary by region and by unit. Obtain local quotes before you decide.
Use current instructions from the responsible organization. This guide is a planning aid, not an official decision or a substitute for qualified advice.
Turn daily hot-water use, a temperature rise, and an electricity rate into an annual and monthly cost.
This App estimates cost with a simple arithmetic model. It does not read your meter, measure efficiency, or replace a bill.
You enter every number yourself. The sources support the method and the limits. They do not produce a result for your specific case. Keep the original documents next to the sheet you build.
The App computes the worked example with your own numbers, in your browser.
APP 1
Turn daily hot-water use, a temperature rise, and an electricity rate into an annual and monthly cost.
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Open Water Heater Annual Energy CostThe App runs in this browser. It does not send or save entries. Copy, download, or print only when you choose.
This guide uses short, direct instructions as an ASD-STE100-style writing target. It is not a formal certification.
Companion App: Water Heater Annual Energy Cost. It runs in this browser and does not upload your entries.
This guide is edited for clarity and checked against the sources it links. It is not a substitute for official instructions or qualified advice. A linked source does not show that every person needs this guide.