Is the ENS-40 110 a good fit for your replacement?
The A.O. Smith ENS-40 110 ProLine is a short, conventional electric storage water heater with a 40-gallon nominal tank. It can be a practical option when a full-height tank will not fit but the household needs more hot-water capacity than some compact lowboy models provide. Water Heating Experts reviews the existing water heater, daily use, installation access and electrical supply before recommending equipment for homes in Palm Beach Gardens, Jupiter and surrounding communities.
A.O. Smith lists 37 gallons of rated storage and a 55-gallon first-hour rating for this model. First-hour rating measures delivery under standardized test conditions, not the number of gallons inside the tank or a guarantee of uninterrupted showers. For households that regularly run out of hot water, we look at peak demand and recovery rather than relying only on the nominal gallon label.
Why a short, rather than a tall or lowboy, water heater?
The ENS-40 110 measures 49¾ inches high and 20½ inches in diameter. It has top-mounted, ¾-inch water connections. Those measurements describe the heater itself; the installation must also accommodate piping, valves, access to the heating elements, drainage and removal of the old tank. A 40-gallon label alone does not guarantee an existing heater can be replaced without changes.
The A.O. Smith ENLB-40 110 lowboy is shorter and wider—32 inches high by 23 inches in diameter—with 38 gallons nominal and a 51-gallon first-hour rating. For a location with limited vertical clearance, its shape may work better. If there is room for a taller and larger-capacity tank, we can also compare the A.O. Smith ENT-50 130. We check actual dimensions and household demand before choosing.
Electrical supply and hot-water recovery
In the standard ENS-40 110 configuration, A.O. Smith specifies 240-volt power and two 4,500-watt elements. Its maximum rated input is 4,500 watts, not 9,000 watts; the heating elements operate non-simultaneously in the standard configuration. The published recovery rate is 21 gallons per hour at a 90°F temperature rise. We verify the supplied unit’s nameplate and the existing circuit, breaker and wiring as part of selecting the installation.
The listed efficiency is 0.92 Uniform Energy Factor (UEF). This is an electric resistance storage tank, not a heat-pump model. If your main goal is lower operating energy use, and you have the necessary space and suitable installation conditions, ask us to compare hybrid heat-pump water heaters.
Tank protection, maintenance and warranty
A.O. Smith describes Blue Diamond glass tank lining, a CoreGard anode rod, a DynaClean sediment-reduction diffuser, an Incoloy stainless-steel lower element and a brass drain valve on this model. These features are designed to help protect the heater, but they do not eliminate the need to follow the manufacturer’s maintenance instructions. We also check water-quality concerns and whether replacing piping, a shutoff valve or other installation components is appropriate.
The manufacturer lists a six-year limited tank and parts warranty for the ENS-40 110. Coverage depends on the written terms and circumstances of installation and use; manufacturer parts coverage should not be confused with free installation or service labor. WHE confirms model availability, the final work scope and any applicable installation coverage during your estimate.
ENS-40 110 frequently asked questions
Does the ENS-40 110 hold 40 gallons?
A.O. Smith lists 40 gallons as its nominal capacity and 37 gallons as its rated storage volume. The separate 55-gallon first-hour rating measures standardized hot-water delivery over the first hour, not tank volume.
How short is the A.O. Smith ENS-40 110?
It is 49¾ inches tall and 20½ inches in diameter, excluding extra space needed for piping and service. We must measure your entire installation area before confirming it will fit.
How is the ENS-40 different from the ENLB-40 lowboy?
The ENS-40 110 is taller and narrower, with 37 gallons rated storage and a 55-gallon first-hour rating. The ENLB-40 110 lowboy is 32 inches high by 23 inches wide, with approximately 35 gallons of rated storage and a 51-gallon first-hour rating. Which one makes sense depends on space and hot-water needs.
Does this require a 240-volt electrical circuit?
Yes, the standard ENS-40 110 configuration is specified for 240 volts and has 4,500 watts of maximum input. WHE checks the exact unit’s label and existing electrical installation to confirm compatibility and any required work.
Can WHE install this model in Palm Beach Gardens or Jupiter?
We serve Palm Beach Gardens, Jupiter and nearby Palm Beach County communities. Mention ENS-40 110 when requesting a free installation estimate. We will confirm service location, suitability, availability and scheduling before installation.
Compare replacement options with WHE
For a helpful starting point, send a clear photo of your current heater’s model label along with a wider photo showing the surrounding space and water connections. Explore our A.O. Smith water heater options or electric water heater replacement service. We can then compare the equipment and the installation work needed.
Technical references: A.O. Smith ENS-40 110 manufacturer product page, A.O. Smith ProLine Standard Electric specification sheet (March 2025), installation and use guide, and residential limited warranty. Confirm the supplied unit’s data plate and current installation instructions before work begins.