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Do I need a thermal expansion tank?

When room temperature water is heated to 120 degrees it expands 3% in volume.  This expanded water has to go somewhere and often times this stress is the final nail in the coffin for an aging water heater tank.  Thermal expansion tanks offer longer longevity to all “tank type” water heaters, by preventing premature failure caused by thermal expansion.  Thermal expansion tanks are small steel tanks with an internal bladder, which is designed to take in the expanded water/ stress, and away from your expensive water heater.

Bock 51e / expansion tank

Thermal Expansion Tank Pricing is relatively inexpensive to replace at $40-60 (unit cost,) but be aware, there is an additional labor investment required to add a new one into an existing system for about $225 (total parts & labor).   Adding a Thermal Expansion Tank is an especially wise investment for all large, “high-end” and otherwise all expensive “tank type water heaters.”   Oil fired water heater tanks are among the most expensive types out there, which is why we highly recommenced adding a thermal expansion tank to every new oil fired water heater installation and oil fired water heater tank replacement service.

Learn more about Expansion Tanks from this link.  Watts, one of the water heating industries leading manufactures of expansion tanks and other water heating performance and safety devices.

Why doesn’t everyone have a thermal expansion tank?   It All Depends On The Incoming Water Pressure Entering Your Home Or Business!!   If you have pressure over near or over 100 pounds, you need a pressure reducing valve, check valve & thermal expansion tank.   High pressure water supply happens in areas where there the water supply is far from where it’s used.  Since  Connecticut has ample supply and short distances from supply to point of use, most of our water supply is around 30 pounds.

In most states, a thermal expansion tank is required by plumbing code but not here in Connecticut.  Since they are looked at as an “add-on,” and not present as a benefit by your standard under-professional plumber, many homeowners pass on all what seems like an additional charge that isn’t absolutely necessary.  After all- the last water heater lasted 15+ years without one.

Note: We never want our clients to feel like we are trying to sell them something they don’t need, which is why we strive to educate our clients all all possibilities to increase your water heaters total service life, and offer high-efficiency alternative options.

Do I really need a thermal expansion tank?   If you have a full family in your home using hot water regularly you can get away without having one, because by using hot water throughout the day you are allowing the pressure out/ preventing the water from ever getting a chance to expand.   On the flip side-  If you have only 1 or 2 people in the home, you travel on the weekends or for any extended lengths of time you really should have a thermal expansion tank on your water heater, because your allowing the water heater to build up heat over days if it being on and not being used.  That pressure has to go somewhere and since we live in the 3rd dimension everything has a reaction, not always equal, but always opposite.  The pressure will cause the water heater to bust, or the T&P valve to open, emptying hot water on to your floor when your not home.  Either result is something all homeowners want to avoid.