## January 20, 2009

### Whats cheaper a shower or a bath?

I always take showers and for whatever reason I had assumed that a shower wasted more water than a bath. But then I came across a page on the web that claimed otherwise. So I decided to run the math for myself and figure it out.

Shower:
A typical shower would run about 10 minutes. With a shower head that flows at 2.5 gallons per minute that means you'd use 25 gallons of hot water for the shower. Water costs 1-2¢ to heat. Therefore a 10 minute shower would cost you 25-50¢.

Bath:
A typical bathtub has about a 60 gallon capacity. However some of that area will be displaced by the person in the tub. Exactly how much area your body will displace will depend on how big of a person you are. However we can at least look at the average. The average American is about 75kg so they would displace roughly 75 liters or about 20 gallons. So you'd have to put about 40 gallons of water in a tub to fill it with a person. To heat 40 gallons of bath water would cost 40-80¢.

A typical shower is cheaper than a typical bath.

It will vary of course depending on exactly how long your showers are, how much water you use in a bath, how big your body is, etc. But on average it appears that showers are more frugal for average adults.