How To Speak “Hot Water”

You’ll make a smarter choice if you understand these water heating terms:

Limited Warranty
The "Limited Warranty" on the tank and parts is the number of years after installation that Reliance will replace the water heater at no charge if the tank leaks, or replace component parts if they malfunction. Both tank and parts warranty apply if failure is due to manufacturing defect. Complete details on Reliance Water Heater Warranties are included with the water heater, or are available from the Reliance Customer Assistance Center (click here). Reliance has a variety of basic warranty choices...

  • 12-Year Tank and Parts Warranty.
  • 9-Year Tank and Parts Warranty.
  • 6-Year Tank and Parts Warranty.

Rated Storage Volume
How much water does the tank store? Enough storage is vital to ensure abundant hot water during the first hour of peak demand.  

The amount of gas or electricity used per hour to heat water in the tank. Input is expressed in BTUs (British Thermal Units) for gas water heaters, and watts for electric water heaters. Higher input means the water heater can heat more water faster when needed.  

Recovery (at 90° Rise)
Converts Btu or watt input into gallons heated in one hour (GPH). For example, a 40,000 Btu gas water heater recovers, or heats, 41 gallons in one hour. 90° Rise means water temperature was increased by 90°F.  

First Hour Output
Also called "First Hour Rating," this "peak demand" figure estimates how much hot water the water heater will deliver during the first hour after you start using hot water. First Hour Output combines the heater's storage capacity with its recovery capability during one hour of operation.  

Flammable Vapor Ignition Resistant (FVIR) Water Heater
FVIR water heaters are designed to prevent the ignition of flammable vapors outside of the water heater. Flammable vapors may be present because a flammable material, such as gasoline, is improperly handled and stored in the vicinity of the water heater. Because water heaters need air to operate, they can potentially pull in nearby flammable vapors that are improperly released. FVIR water heaters are designed to contain the ignition of flammable vapors that are drawn into the combustion chamber and prevent ignition outside of the water heater.


Remember, gasoline should never be used or stored indoors, should always be stored in sealed approved containers, and should only be used as a motor fuel!

Reliance Water Heaters