Home Energy Calculators
Low-flow showerhead payback.
Dropping from the 2.5 gpm of a standard showerhead to a 2.0 gpm WaterSense model cuts shower water by 20%, and because most of it is heated, you save energy too. Enter your showers, prices and showerhead cost to see yearly savings and the payback time. Runs in your browser; nothing is sent or stored.
Your numbers
Result
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Worked example
Four showers a day of 8 minutes each on a 2.5 gpm showerhead use 80 gallons a day; at 2.0 gpm they use 64. The 0.5 gpm difference saves 0.5 x 8 x 4 x 365 = 5,840 gallons a year (20% less), worth $46.72 at an example $8 per 1,000 gallons. If 70% of that water is heated by an electric heater adding 70°F, heating 4,088 gallons takes about 700 kWh, or $104.99 at $0.15 per kWh. Total saving is $151.71 a year, so a $30 showerhead pays back in about 2.4 months. Example inputs: replace them with your own.
How it works
Gallons saved = (old gpm - new gpm) x minutes x showers per day x 365. Water saving = gallons / 1,000 x price. Heating saving = gallons x hot share x 8.345 lb x temperature rise / 3,412 Btu per kWh (or 100,000 Btu per therm, per US EIA) x energy price / efficiency. Payback = showerhead price / yearly saving.
Why the numbers differ from the EPA's. The EPA estimates the average family could save 2,700 gallons a year and more than 330 kilowatt hours of electricity with WaterSense labelled showerheads. Your result depends on your showers, your mix of hot water and your heater, so enter your own figures.
Not covered. Some people shower longer with a weaker flow, which cuts the saving. Check flow with a bucket and stopwatch if you are unsure of your current showerhead.
Sources and basis (pages opened 2026-10-08): US EPA WaterSense, Showerheads; US EIA, What is a British thermal unit (Btu)?.
This is a planning estimate and not professional plumbing, electrical or financial advice. Rates, fixtures and equipment vary, so confirm important decisions with your utility, the manufacturer or a licensed professional.
FAQ
Does a low-flow showerhead save money?
Usually, if you keep your shower length. It saves the water and the energy used to heat it. Enter your own prices to see the yearly saving and payback.
What flow does a WaterSense showerhead use?
The EPA says WaterSense labelled showerheads must use no more than 2.0 gallons per minute, compared with 2.5 gpm for standard showerheads.
How much could a family save?
The EPA says the average family could save 2,700 gallons a year and more than 330 kWh of electricity by installing WaterSense labelled showerheads.
What share of shower water is hot?
It depends on your shower temperature and your water heater setting. The default is an example; lower it if you shower cooler.
How do I measure my current showerhead's flow?
Time how long it takes to fill a bucket of known size, then divide gallons by minutes.