Shower Cost Calculator: What Does One Shower Cost?

How the calculation works

A shower’s energy cost comes from the hot water it uses. The calculator finds the gallons, the share that is hot, the heat needed to warm that water, and the energy your water heater buys to supply it.

Gallons per shower     = minutes × showerhead flow (gallons per minute)
Hot gallons            = gallons × share of hot water
Heat needed (BTU)      = hot gallons × 8.34 × (tank setting − incoming water temp)
Energy bought          = heat needed ÷ water heater UEF
Cost per shower        = energy ÷ 3,412 × price per kWh   (electric and heat pump)
                       = energy ÷ 100,000 × price per therm (gas)
Cost per year          = cost per shower × showers per week × 52

8.34 is the weight of a gallon of water in pounds; it takes about 1 BTU to warm 1 pound of water by 1°F. UEF (Uniform Energy Factor) is the federal water heater efficiency rating. The tool’s presets are 0.93 for an electric tank, 0.64 for a gas tank and 3.5 for a heat pump water heater, within the ranges ENERGY STAR reports.

Prices. The default electricity price is 18.31¢ per kWh (EIA, U.S. residential, July 2026). The gas preset is about $1.35 per therm (EIA, residential, January 2026).

Flow rates. Federal rules limit showerheads made since January 1, 1994 to 2.5 gallons per minute at 80 psi, and WaterSense labeled heads to 2.0 gallons per minute or less.

The result is energy only. Water and sewer charges vary widely by city, so they are not included.

Worked example

The default household takes 14 showers a week, about one a day for two people.

1. Each shower lasts 8 minutes with a 2.0 gallon-per-minute showerhead: 16 gallons.
2. 70% of that water is hot, heated from 55°F to 120°F by an electric tank (UEF 0.93) at $0.18 per kWh.
3. Energy cost per shower: $0.34.
4. Energy cost per year: $251.
5. Water used per year: 11,648 gallons.

A second example

A busier household takes 21 showers a week, 10 minutes each, with an older 2.5 gallon-per-minute head. Hot water comes from a gas tank (UEF 0.64) at $1.35 a therm.

• Water per shower: 25 gallons
• Energy cost per shower: $0.20
• Energy cost per year: $219
• Water per year: 27,300 gallons

Gas makes each shower cheaper in energy than the electric example, even though it is longer. But this household uses more than twice the water, which shows up on the water and sewer bill.

Keep the default 8-minute shower but switch to a heat pump water heater (UEF 3.5) at $0.18 per kWh, and the energy cost drops to $0.09 a shower and $67 a year.

What your result means

Cost per shower is the energy price of one shower. Cost per year is the total for your household, so you can see what a habit change is worth over twelve months.

The easiest savings come from flow and time. A WaterSense showerhead and a shorter shower each cut gallons and energy together. Upgrading the water heater only cuts energy, but by more: see the full comparison in the water heater cost calculator. If you are thinking about a heat pump model, our heat pump water heater guide explains what to expect.

Local factors that change the answer

Incoming water temperature. Groundwater is colder in northern states and in winter, so each shower takes more energy then. The tool uses one temperature for the year.

Energy rates. Electric rates vary a lot by state and by time of day. If you are on a time-of-use plan, the time your tank reheats matters.

Water and sewer charges. Some utilities bill sewer based on water use, so cutting gallons can save twice. Check your water bill for the price per 1,000 gallons and multiply by the gallons per year shown here.

Rebates. Some water utilities give away or discount WaterSense showerheads. The federal 25C tax credit for heat pump water heaters ended for property placed in service after December 31, 2025; our guide to energy tax credits in 2026 explains what changed. For more no-cost and low-cost ideas, see our guide on how to lower your energy bill.

Common mistakes

• Assuming the showerhead flows at its rated maximum when the water pressure is lower, or below it when the flow restrictor was removed.
• Forgetting to count every person’s showers in the weekly total.
• Using the gas price for an electric water heater, or the reverse.
• Treating the result as the full cost; water and sewer charges are extra.
• Leaving the share of hot water at 100% when you mix in cold.

Limits of this calculator

The tool assumes a constant flow, one incoming water temperature and a fixed hot-water share. It uses rated UEF values, and it ignores heat lost in pipes between the water heater and the shower, as well as standby losses not captured by the rating. It does not include water or sewer charges. This is an educational estimate, not advice.