different types of water heatersWhen you’re choosing a new water heater, it is essential to choose the right size for your family. If your heater is too small, you’ll find you run out of hot water quickly, perhaps even in the middle of your shower. On the other hand, water heaters that are larger use more energy. To save on your utility bill, you want to choose as small of a water heater as you need.

Here’s how to find out what is the right size water heater for your home.

General Rules about Water Heater Size

In general, every person in a home needs 12 gallons of water heater space. Size can be easily guessed using this rule:

  • One and two-person homes need the smallest water heaters available, at 30 gallons.
  • Three person homes need 40-gallon water heaters.
  • If you’re a family of four, you need a 50-gallon water heater.
  • Five or more people may need anywhere from a 50-gallon to 80-gallon water heater.

There are many exceptions to this rule. Larger families often use water-saving strategies like spacing out their showers or washing all of their dishes by hand. If you do, you may be able to get away with a smaller tank.

Or, couples might use a lot of water at one time, finding that they have to shower within the same hour to both get to work on time, or that one person tends to start the laundry just as the other does the dishes.

If you think your family might be an exception, you can get a more precise number to work with.

How Much Hot Water Will I Really Use?

All hot water tanks have a first hour rating (FHR) which expresses how much hot water they can produce in the first hour of use. All you need to know is how much hot water you’ll use in your most demanding hour, and then pick a tank with a sightly higher FHR.

Consider your daily and weekly schedule, and estimate when you demand the most water. Then, use the chart below to add up how many gallons you use based on what activities you do.

Activity or Appliance Average Number of Gallons Used
Shower 5 gallons every five minutes
Shaving 1-2 gallons
Bathing 40-50 gallons
Washing machine 6 gallons
Dishwasher 6 gallons
Washing by hand 4 gallons
Preparing food 4 gallons

Just remember that this chart is an estimate. If you take longer showers than most people or have low-flow fixtures, you may use more or less water than average.

To be even more specific, refer to your appliances and fixtures’ user manuals to discover exactly how much water they use. Just remember only to count hot water usage, as the amount of cold water you use doesn’t matter when you’re choosing your water heater.

Once you’ve added up your total gallons, all you have to do is pick out a water heater with an FHR at or slightly above your total.

What Size Tankless Water Heater Do I Need?

Of course, the rules for picking the right tankless water heater are a little different. If you’re near Tracy, CA, consider calling our tankless water heater specialists to help you choose the right unit for your home, family, and lifestyle.