Taking a shower consumes 17% of the total indoor water use in the United States and generates tons of CO2 emissions from heating all that glorious hot, hot, hot, soaking water.
According to Home Water Works, in an average home, showers are typically the third largest water use after toilets and clothes washers. The average American shower uses 17.2 gallons (65.1 liters) and lasts for 8.2 minutes at average flow rate of 2.1 gallons per minute. Other sources estimate, that its significantly higher anywhere between 25-50 gallons per shower. The point is that water, especially hot water, is flowing quickly and there is fossil fuel being burned and CO2 being emitted for every second of hot water. We want you to still enjoy the shower in a healthy way, but just be mindful of those CO2 emissions
Everyone loves and benefits from a hot shower. This isn’t an indictment on showers, just an encouragement on how to be smarter about it and get more out of both your soap and the energy used to heat that water. All while still enjoying the benefits of a hot shower.
If every US resident used just one less gallon of water during every shower, that would cut the country’s water use by 85 billion gallons each year – roughly equal to a large reservoir that would definitely help the drought conditions affecting many parts of the country.
Saving water in the shower can easily translate to saving money on the water bill. While water is still relatively cheap ($0.01 cents per gallon) and abundant in many places (for now).
Consider Taking A Shower… The Navy Way
Navy Shower Technique – This method of showering got its name from the navy as a means of saving water while at sea. It’s simple: Get completely wet, turn off the water, lather up with soap, shampoo, shaving cream, etc., let these cleaning agents do their work, and after a few minutes, turn the water back on and rinse. Seems logical, right? Rather than have the freshly applied soaps quickly wash off, let the soap and shampoo soak in for a minute and then rinse clean.
Showering this way can use as little as 10 gallons of water every shower. PLUS, it gives the soap and conditioner a chance to activate and thoroughly do its job. Makes a ton of sense instead of immediately washing it off and down the drain, only to apply more suds to get the job done.
Controlled Flow Shower Heads These shower heads limit flow and are a sensible alternative. If the thought of showering the “Navy” way doesn’t exactly have you jumping for joy, installing low flow shower heads (low flow refers to using 2.0 and fewer gallons per minute [GPM]) is another great way to combat shower water consumption.
A Little Conservation Every Shower Adds Up Quickly
In the big scheme of things, the cost of the hot water is really insignificant. Monetarily it’s relatively inexpensive because energy is so cheap in the U.S. (for now). This is mainly because the total price does not include the pollution costs (the greenhouse gasses emitted) heating that water. Keep in mind, that the infrastructure of the water system and shower itself can be expensive (the pipes, tiles, faucets, shower doors or curtains)…are the embodied energy already invested so that you have a shower option.
Some people take 300-400 showers a year consuming considerable amounts of energy. Let’s assume 300 showers a year at 25 gallons per shower – consumers 7500 gallons every year. 60,000 pounds of water spraying over you and down the drain. Saving just a part of every shower, say 5 gallons equates to 1500 gallons of warm, mostly hot water every year. As you can see, it adds up quickly.
Once the navy way becomes habit after a few tries, you won’t even notice it.
How Much Energy is Consumed Heating Water with These Different Heating Options?
Calculation are with help from Ask Mr. Electricity
How Much Energy is Consumed?
- A Btu, or British thermal unit, is the amount of energy needed to raise one pound of water from 60°F to 61°F at sea level.
- A gallon of water weights 8.33 lbs.
- If the incoming water is 60°F and we want to raise it to 123°F, that’s a 63°F rise.
- Heating a gallon of water thus requires 8.33 x 63 = 525 Btu’s, at 100% efficiency.
Cost to Heat Water in a Gas Tank:
- A typical gas tank water heater is only 59% efficient. So it takes 525 ÷ 59% = 890 Btu’s to heat a gallon of water in a gas tank.
- One therm is 100,000 btu’s. So one Btu is 0.00001 therms. (Pacific NW Natl. Lab.)
- 890 Btu’s is 0.0089 therms.
- So it takes 0.0089 therms to heat a gallon of water, or 0.0089 x 40 = 0.356 therms to heat a 40-gallon tank.
- At $1.42/therm, it costs 0.356 x $1.42 = $0.51 to heat a 40-gallon tank.
Cost to Heat Water in an Electric Tank:
- A typical electric water heater is 90.4 to 95% efficient. Let’s call that 92.7% on average.
- So it takes 525 ÷ 92.7% = 566 Btu’s to heat a gallon of water in an electric tank.
- One kWh is 3413 Btu’s, so one Btu is 0.000293 kWh.
- 566 Btu’s x 0.000293 kWh/Btu = 0.166 kWh.
- So it takes 0.166 kWh to heat a gallon of water, or 0.166 x 40 = 6.63 kWh to heat a 40-gallon tank.
- At $0.12/kWh, it costs 6.63 x $0.12 = $0.80 to heat a 40-gallon tank.”
Consider Tankless Water Heaters
They highlight the key advantages and explain, “On average, a tankless water heater uses 25-50% less energy than a storage water heater, which saves money (and reduces your carbon footprint). The tankless water heater (also commonly called an on-demand water heater) conserves energy by heating water only when a faucet is opened. Most tankless heaters are powered by propane or natural gas, but a smaller percentage use electricity. The primary advantage is that they eliminate the cost associated with maintaining 40 gallons of hot water in a holding tank.”
Green Blizzard installed an on-demand water heater in its Camden, Maine studio and the team absolutely loves it. Our green visitors never deplete our hot water? From a carbon footprint perspective, we think tankless water heaters are the wave of the future.
Many new homes are constructed with control flow shower heads that consume 2.5 gallons of water per minute (GPM). You can find low flow shower heads that use just 1.0 GPM. Switching to low flow can cut your shower usage from 20-40% and the shower heads cost anywhere from $9-$50 (depending on the manufacturer and design).