Once you have all the numbers you need, input the information into an expansion tank size calculator offered by brands Amtrol or Watts. The price of a 2-4.4 water heater expansion tank on its own ...

This Amtrol THERM- X - TROL ST-5 Expansion Tank is designed to relive the pressure build up in your water heating system safely and effectively. Amtrol ST-5 THERM-X-TROL Expansion Tank, 2 Gallon ...