Is the A.O. Smith ENT-55 100 right for your home?
The A.O. Smith ProLine ENT-55 100 is a conventional 55-gallon tall electric storage water heater for households that need more stored hot water than a typical 40- or 50-gallon tank. A larger tank is not automatically the right replacement, however. At Water Heating Experts, we check the existing installation, your household’s hot-water use, the available space and the electrical circuit before recommending equipment in Palm Beach Gardens, Jupiter and nearby communities.
A.O. Smith lists 55 gallons of nominal and rated storage and a 72-gallon first-hour rating for this model. The first-hour rating measures hot-water delivery under standardized conditions; it is not the amount physically stored in the tank or a promise of uninterrupted showers. For households with back-to-back showers or overlapping hot-water use, we assess the demand before recommending a size.
Tank size and installation considerations
The ENT-55 100 measures 56½ inches high and 24 inches in diameter, with ¾-inch top water connections. Its dimensions differ from the familiar 50-gallon tall format: the A.O. Smith ENT-50 130 is taller at 59 inches but narrower at 20½ inches. That extra diameter can matter when a water heater is in a closet or a restricted garage corner.
When planning a replacement, WHE checks the clearances above and around the tank, removal access, existing piping and shutoff valves, electrical connections, the relief-valve discharge, and drainage or pan requirements. If the current water heater is in an attic or another hard-to-access location, we can also discuss whether relocating it to a more accessible garage location is appropriate for the project.
Hot-water delivery and electrical requirements
The standard ENT-55 100 configuration uses 240-volt power and two 4,500-watt heating elements, with a manufacturer-listed maximum input of 4,500 watts. The standard arrangement does not energize both elements simultaneously, so their individual ratings should not be added to claim a 9,000-watt load. A.O. Smith lists recovery at approximately 21 gallons per hour at a 90°F temperature rise. First-hour delivery and recovery are different measurements.
The manufacturer’s technical specifications list a 0.93 Uniform Energy Factor (UEF) for this model. The general product description lists 0.94, but the technical table and March 2025 specification sheet agree on 0.93, which is the figure we use here. This is a conventional electric resistance tank, not a heat-pump water heater. If energy use is a key consideration and the installation area permits, WHE can compare hybrid heat-pump water heater options before you decide.
Tank protection, maintenance and warranty
Manufacturer-listed features include an Incoloy stainless-steel lower heating element, Blue Diamond glass tank lining, a CoreGard anode rod, a DynaClean diffuser to help reduce sediment buildup and a brass drain valve. These components support the heater’s design, but maintenance and water quality still matter. We can review service needs and any necessary installation changes when assessing your existing equipment.
A.O. Smith lists a six-year limited tank and parts warranty for the ENT-55 100, subject to the written warranty terms. Manufacturer coverage is separate from installation labor and removal or replacement costs. Equipment availability, final installation scope and any applicable WHE labor coverage are confirmed with your estimate.
ENT-55 100 frequently asked questions
Does the ENT-55 100 really hold 55 gallons?
Yes. A.O. Smith lists 55 gallons for both nominal capacity and rated storage. Its 72-gallon first-hour rating is a separate measure of hot-water delivery during a standardized test.
Will it fit where my current 50-gallon water heater sits?
Not necessarily. The ENT-55 100 is 56½ inches high and 24 inches in diameter. Some 50-gallon tanks are narrower, even when taller. WHE measures the space, connections, service access and removal path before recommending a replacement.
What is the difference between the ENT-55 100 and ENT-50 130?
The ENT-55 100 has 55 gallons of rated storage and a 72-gallon first-hour rating, compared with 46 gallons rated storage and a 62-gallon first-hour rating for the ENT-50 130. The ENT-55 is wider, so we compare both physical fit and household demand.
Does this model require 240-volt power?
The standard ENT-55 100 is listed for 240 volts with two 4,500-watt elements and 4,500 watts maximum input. WHE checks the exact heater nameplate and your existing circuit, wiring and breaker before confirming suitability.
Can WHE install this model in Palm Beach Gardens or Jupiter?
Water Heating Experts serves Palm Beach Gardens, Jupiter and nearby Palm Beach County communities. Mention ENT-55 100 in your free installation estimate request. We will confirm the address, suitable equipment, availability and installation requirements.
Compare water heater options with WHE
For an accurate recommendation, text us a clear photo of your current heater’s model label and a wider photo showing the surrounding space and connections. We can compare A.O. Smith water heater installation options and explain the work needed before confirming equipment or price.
Technical references: A.O. Smith ENT-55 100 manufacturer product page, ProLine Standard Electric specification sheet (March 2025), installation and use manual, and limited warranty. The product’s introductory description differs from its technical specification on UEF; this listing uses the technical 0.93 value. Confirm the supplied unit and current installation instructions before work begins.