2 Gallon Expansion Tanks...Hot water VS Well expansion tank

Can anyone solve this mystery for me? When it comes to putting a 2 gallon thermal expansion tank on a hot water heater, can a person opt to use a 2 gallon well pressure expansion tank?

What is the difference between these expansion tanks?

I will use the following example that Lowes sells the 2 gallon hot water tank expansion tank for $40.00 and the 2 Gallon well pump expansion tank for $50.00. These are the "LPT2" series tanks.

I wonder if most people complain that typical hot water expansion tanks experience bladder failure in 3 years? Do you think that the well style expansion tank has a stronger internal bladder and will last longer?

They should be the same tank, because a 2 gallon "well pump expansion tank" would be absolutely useless for a pump system, (and well pumps do NOT have an expansion problem in the first place).

hj said:

...a 2 gallon "well pump expansion tank" would be absolutely useless for a pump system...

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A 2 gallon pressure tank on a well pump would be fine for a sprinkler system that is matched to the GPM of the pump so that it doesn't cycle. Also would work with a CSV.

WH expansion tanks are designed to be installed on the cold water supply and won't work well on the hot side - the bladder dies earlier. Both a well tank and a WH would normally only have cold water feeding them, so, it's likely either should work. A well tank bladder would probably see MUCH more expansion/contraction of the volume of water, and to survive a decent service life, the bladder may be more robust to take the regular large excursions as the pump cycles. A WH, depending on its size, may only need to accommodate a cup or so from expansion, a well tank much more.

Interesting you found a thermal expansion tank at Lowe's. My Lowe's doesn't even know what they are. That aside, I have had my expansion tank in place for 5 years and it is still just fine.

hj said:

They should be the same tank, because a 2 gallon "well pump expansion tank" would be absolutely useless for a pump system, (and well pumps do NOT have an expansion problem in the first place).

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Unless its on a variable speed constant pressure well system or a jet pump booster system and then 2-gallon well tanks are the norm.