How to decide what size water heater tank is best for your home

If you’re in the market for a new water heater tank, it’s important that you make sure you get the right size. To do so, here are some expert tips to follow:

Consider the Size of Your Household

The general industry rule is that the more people who live in your home, the more water you will use and the bigger water heater tank you will need. We recommend factoring in 12 gallons of water for each person in your household. But, there’s more to consider than just the size of your household, including:

Water Usage Habits

Some families with multiple bathrooms will all shower at the same time in the morning, of course, which drives water usage up. How often you do laundry, dishes, wash hands, mopping, and so on will also impact your hot water usage.

Estimate Your Peak Water Usage

To create an estimate that includes your water usage habits, you should estimate the maximum amount of water you use in an hour and measure it against the water heater’s first-hour rating. This rating is different from the tank’s size because it calculates how much hot water the hot water heater can produce in an hour when it starts with a fully-heated tank, taking heat loss into consideration as unheated water fills the place of water being used. You should be able to find the first-hour rating on the top left corner of the water heater’s EnergyGuide label.

To help you estimate the maximum amount of water your household uses in an hour, you should determine the time of day when your household uses the hottest water. Next, you will calculate the amount of water used. Here’s a basic estimate of how much hot water common household activities use:

  • Shower: 1-2 gallons/minute
  • Shaving: .05 gallons/minute
  • Food prep and hand-washing: 4 gallons total, 2 gallons/minute
  • Automatic dishwasher: 6 gallons
  • Washing machine: 7 gallons

So, if you have two people showering in the same hour while the dishwasher and washing machine are running, add (minutes in the shower times two) + (minutes in the shower times 2) + 6 + 7 to determine the peak hour usage.

Water Heater Constraints

Water tanks are a cost-effective solution for hot water. Compared to other options, water tanks don’t cost very much to install or maintain, and you can heat the water via gas or electricity. But, before you rush out to buy a bigger water tank, there are some other things to take into consideration. Mainly whether or not you have enough space to store it. 


You should also remember that you may have to increase the exhaust pipe size when you increase your water heater size. Having a properly sized exhaust pipe will ensure your unit can draft properly. A water heater that does not draft properly will have issues and could leak carbon monoxide, which is extremely hazardous to your household.

If you need help estimating the water heater tank’s size that will fit your household’s needs and size best, or you want expert help to find the best type of water heater for your home, contact a professional water heater technician today.


Contact Our Plumbing Pros Today!

For all your residential and commercial heating and air conditioning needs in the greater Memphis area, count on Choate’s. Since 1958, Choate’s has been the go-to source for air conditioning, heating, and plumbing services in Memphis, TN, and surrounding areas. Contact us today to find out more!

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