How to Choose a Water Heater


Reliance® offers over 100 gas and electric tank type choices because choosing a water heater is definitely not a “one size fits all” process. Your top priority is to choose a model that makes sure you will have enough hot water by matching your family size up with the right First Hour Rating (see chart below). But first, here are a few basic questions to start with to make sure you get the right type of water heater and a unit that will fit in the space occupied by your current unit.

Buyers Guide

Other things to consider

  • Is the water heater natural gas, propane gas, or electric?
  • Is the water heater for a mobile home? 
  • What is the height available for installation, measuring from the floor to the closest permanent obstruction above the water heater?
  • What is the diameter of the current water heater, measuring across the top of the unit?

Next, determine the First Hour Rating target using the charts below.


These are minimum requirements. To handle high usage factors, you should increase the First Hour Rating target as follows:


Add 10 gallons if you have an oversized bathtub or whirlpool.
Add 10 gallons for every teenager living in the home.