Jadnashua
Retired Defense Industry Engineer xxx
The calculators to determine the size ET required take into account the size of the water heater tanks, how cold the inlet water is, and how much you raise the water temperature for storage. Water expands a known amount based on the amount of temperature change, so the amount of needed volume is fixed, regardless of the brand. Once you know that, you want at least the size they recommend...larger won't hurt, and might make things last a little longer since it won't have to flex as far. You don't want to undersize it, since that stresses the bladder and will shorten the life. Worst case, it won't be able to keep the pressure as stable.
Take your worst case, winter incoming water temp which can be as much as 50-60 degrees colder than the summer temps.
Take your worst case, winter incoming water temp which can be as much as 50-60 degrees colder than the summer temps.
