Do You Save More Money Taking a Shower or a Bath?

When you live in an old house like we do, there’s only so much that can be done to boost energy efficiency. Old pipes, old wiring, and other hard-to-reach systems are impossible to upgrade without a costly remodel. To save money, our family has learned to scale back the utility use in all areas instead.

One old energy adage that Grandma still adheres to is the idea that taking a bath uses less water than taking a shower. Is this really true or just another energy myth? The answer all depends on the age of your home and how long of a shower you take.

Gallons per minute.
Homes built prior to 1992 were usually fitted with shower heads that use around 5 gallons a minute of water (known as GPM). If you have one of those deluxe “cascading” shower heads with the variable settings, the usage is closer to 7-8 gallons a minute.

To determine just how much water your family uses when showering, multiple the length of time of the shower by 5 GPM. A 7 minute shower for example would use 35 gallons of water. Considering that a bath requires only 30-50 gallons of water, it doesn’t take much of a shower to exceed the water used for a tub bath.

Low flow shower heads.
When our plumber updated a few of our fixtures a few years ago, we asked about switching the shower heads to energy efficient models. All of our showers now have low flow shower heads which use between 1.75 GPM (gallons per minute) to 2.50 GPM. For a seven minute shower, this means we use between 12-17.5 gallons of water which is a significant energy savings compared to a tub bath.

Take the test.
The easiest way to determine if you use more water taking a bath or a shower is by plugging the tub drain stopper the next time you shower. After the shower, look at the level of water in the tub. If it’s far less than the water drawn for a tub bath, then you will save energy by taking a shower instead of a bath. If however the water in the tub has reached the overflow and is draining away, then Grandma’s old piece of folk wisdom is correct and a tub bath will be more energy efficient.

More by this contributor:
How a new shower head dropped our energy use.
Energy savings tips that are best ignored.
No electricity? 5 easy things to check first.