When specifying a water heater, the type of protective lining is one of the most important features to consider. How well a lining protects the steel tank is primarily based on its thickness and coverage of the steel surfaces. Two of the most popular linings are cement and glass.

• Cement linings average ½ inch thick and covers 100% of wetted surfaces.
• Glass linings are typically only 5/1000 of an inch (about the thickness of a sheet of paper) with inconsistent surface coverage, therefore requiring a sacrificial anode rod.

Here’s more information you may or may not know regarding cement-lined water heaters:

• They are one of the longest lasting water heaters on the market.
• They are repairable.
• They are not fragile.
• They are virtually maintenance free.

Long lasting

Cement-lined water heaters are one of the longest lasting and most durable water heaters available. According to a local utility, a cement-lined water heater can easily perform for 20 plus years¹, while glass-lined water heaters last on average 8-12 years².

Repairable

Glass linings by design contain minor imperfections or holidays. These holidays leave the steel tank directly exposed to water, which can then lead to corrosion, and failure of the tank — hence the need for a sacrificial anode. Over time, even a cement lining may begin to show signs of failure—but the cement lining is repairable. Depending on the circumstances, the cement lining can be patched using commercially available cement, or in an extreme case, the entire tank can be relined. There are many service companies who specialize in these kinds of repairs.

Not fragile

A cement-lined tank is essentially a tank within a tank. The cement used to line water heaters expands and contracts at a similar rate to the steel tank, eliminating contrasting forces that could make the lining fragile.

Maintenance free

Glass linings are made of porcelain enamel which have tiny pinholes throughout, exposing the steel tank to water and corrosion. For this reason, glass-lined tanks require sacrificial anode rods to neutralize the electrochemical reactions that would otherwise corrode the tank. Once depleted, if the anode rods are not replaced the steel tank will begin to corrode, at which point the entire water heater needs to be replaced. Because all wetted surfaces are either covered with cement or non-ferrous materials, there is no need for an anode rod in a cement-lined water heater, making them virtually maintenance free.

Hubbell is a leading manufacturer of cement-lined water heaters with expertise that spans over a century. We offer water heaters for most energy sources with storage capacities from 1–10,000 gallons as well as instantaneous and semi-instantaneous water heating solutions. All Hubbell products are designed, engineered, and manufactured for reliability coupled with unparalleled support and service. Contact us today to find out more about our cement-lined water heaters, storage tanks or other water heating products.

Footnotes:

¹ TempAssured Worry-Free Water Heater Lease, UI, Boston, MA, 2017.

² Ahwadmin. “How Long Do Water Heaters Last? Find out What to Expect.” American Home Water & Air, 5 Aug. 2022