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3 Best 40 Gallon Electric Water Heaters for Families of Four

Fact checked by Stephen Conklin

best 40 gallon electric water heater

Only the best 40 gallon electric water heater can guarantee a sufficient hot water supply to a household of three to four. This water-heating appliance minimizes standby heat losses better than gas-powered units, allowing families to maximize their energy consumption.

Choosing a 40-gallon electric water heater can be daunting and confusing for the uninitiated or those with limited water heater knowledge. Hence, we asked seasoned water heater owners and experts what they consider the three most influential factors when buying this appliance. Here they are.

  • Uniform Energy Factor (UEF) Value: The federal government recommends manufacturers put UEF values in their water heaters to inform potential buyers of their offerings’ energy efficiency.

A water heater with a higher UEF value is more efficient than a low-UEF unit (i.e., UEF 0.93 vs. UEF 0.88).

  • First Hour Rating (FHR): This factor describes the hot water volume the 40-gallon electric water heater produces in an hour after filling the storage tank.

Like UEF, a 40-gallon electric water heater with a high FHR value is better. For example, you can choose a 75-gallon FHR unit over a 55-gallon option.

  • Recovery Rate (RR): Using hot water activates the water heater to draw cold water from the supply line and heat it to the desired temperature. The water heater must “recover” more hot water within one hour to ensure continuous hot water consumption.

For example, a 40-gallon electric water heater with a 50-GPH recovery is better than a 30-GPH unit.

Although these three factors are enough for some folks to choose the ideal 40-gallon electric water heater, some families might need other considerations. We will look at these parameters in the comprehensive buying guide and highlight them in the following reviews.

Top 1

Bosch 5000T


Uniform Energy Factor 93
First Hour Rating 51 gallons
Physical Dimensions 61.6 x 18.25 x 18.25 inches

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Top 2

A. O. Smith ENS-40 ProMax

Uniform Energy Factor 0.92
First Hour Rating 55 gallons
Physical Dimensions 50 x 22 x 22 inches

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Top 3

Rheem 72-40-2

Uniform Energy Factor 0.95
First Hour Rating 54 gallons
Physical Dimensions 50 x 24 x 22 inches

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Table of Contents

3 Top-Rated 40-Gallon Electric Water Heaters

1. Bosch Thermotechnology Tronic 5000T 40-gallon Electric Storage Water Heater

Bosch’s Tronic series of electric water heaters are some of the most reliable water heating appliances I know. And its 5000T model is perfect for the modern family of three to four.

With a Uniform Energy Factor value of 93% and a First Hour Rating of 51 gallons, families will never complain of exorbitant electric bills and insufficient hot water supply again. I can imagine the savings families can get from this 40-gallon water heater.

Although A.O. Smith’s ENS-40 ProMax has a slightly higher FHR at 55 gallons, the Tronic 5000T has several innovations that can shame other 40-gallon electric water heater brands.

Unlike other water heaters, this appliance features a pair of premium-quality magnesium anode rods, doubling its protection against corrosion. High-grade glass lines the storage tank’s interior surface to improve its anti-rust properties.

I also appreciate the dual Incoloy heating elements, enabling this water heater to resist oxidation and deformation at high temperatures. The company’s engineers also designed the water heater’s thermal insulation with an R-value of 24, an attribute I find remarkable.

Although taller than the Promax ENS-40 by 11.6 inches, this product’s 18.25-inch diameter should make installations in tight spaces a breeze.

Despite its advanced features, unquestionable craftsmanship, and top water heating performance, this product is still less costly than the ENS-40 ProMax.

Unfortunately, Bosch requires expert installation of this 40-gallon water heater for safety reasons. This attribute might not sit well with folks with a strong DIY spirit.

I strongly recommend this product to families of four. It’s an excellent combination of reliable German technology and impressive water heating at a price that won’t get users bankrupt.

  • Impressive water heating performance: UEF 0.93 and 51-gallon FHR
  • Excellent thermal insulation with an R-24 value
  • Corrosion protection with magnesium anode rods and grass lining
  • Dual Incoloy elements for durability
  • Better space savings with an 18.25-inch-diameter footprint
  • Good value for money
  • Expert installation necessary

2. A. O. Smith ENS-40 ProMax Short Electric Water Heater

A.O. Smith has been making water heaters since 1939, although the company has been around since 1874. It’s one of the most trusted names in water heating, and the company’s ENS-40 ProMax 40 Gallon Short Electric Water Heater has enough bells and whistles to wow buyers.

Some might point out this 40-gallon electric water heater’s 92% UEF (slightly lower than the ES40M’s 0.93). However, I find the difference marginal, considering this water heater has a higher First Hour Rating (55 gallons) than many brands.

My family could enjoy a 20-minute hot shower nonstop or two-and-a-half bath sessions back-to-back. And if we decide to shower simultaneously, we can do that more than twice.

I also love the company’s PEX crosslinked polymer Dynaclean technology. The dip tube might look like any other element, but the revolutionary self-cleaning system sets it apart. Families will never fuss about limescale and sediment buildup again. It also makes cleanups and maintenance a cinch.

This 40-gallon electric water heater might not have the E40M’s anode rods, but it still blasts other competitors with its CoreGard technology. This stainless steel core system gives the water heater exceptional corrosion resistance. I wouldn’t be surprised if this water heater outlasts others.

Although this 40-gallon electric water heater is shorter than the Tronic 5000T by 11.6 inches, its diameter is wider by 2.25 inches. These dimensions can be a concern for some folks. Moreover, it’s substantially more expensive.

This 40-gallon water heater remains an excellent option for families of three to four. It might be slightly pricey, but its FHR and proprietary technologies make up for it.

  • 4500-watt water heater with a 40-gallon nominal capacity
  • UEF 0.92 and 55-gallon FHR for more hot water
  • Ingenious anode rod with proprietary Coregard technology
  • Class-leading DynaClean dip tube for effortless cleanups
  • Durable water heater from a well-established bran
  • A bit stout
  • A bit pricey

3. Rheem 72-40-2 240V/4500W 40 Gallon Electric Water Heater

Rheem launched its first water heater at roughly the same time as A.O. Smith. The company’s 72-40-2 (now called Professional Classic Standard PROE40 2 RH95 MH) remains a competitive option for small families looking for a dependable 40-gallon water heater.

I was surprised to learn this 40-gallon unit has a Uniform Energy Factor of 95%. And here I am, thinking the ES40M’s 0.93 is already impressive. I must commend the company’s designers and engineers for creating a high-efficiency electric water heater.

This appliance’s 54-gallon First Hour Rating is one gallon short of the ENS40’s capabilities. However, what impressed me the most was this appliance’s 21-gallon-per-hour recovery rate, which the company tested at a 90-degree Fahrenheit temperature rise.

Like the ES40M and ENS40, this electric water heater features anti-corrosion and lifespan-extending technologies. For example, I appreciate its Lifeguard heating elements that safeguard tank and anode rod integrity.

Its glass tank interior lining system adds another layer of tank and anode rod protection. At least, I can be confident in using this electric water heater for more than five years without replacing the anode rod.

Cleaning and maintaining this 40-gallon electric water heater is also sweat-free with its user-friendly EverKleen system. Sediments and limescale will be the least of my worries with this technology.

I appreciate the company integrating a junction box next to the water heater’s heating elements. Wiring this appliance to my electrical system shouldn’t pose any issues.

My only issue with this Rheem 40 gallon electric water heater is its price. This water heater is more expensive than the A.O. Smith ENS40.

This 40-gallon electric water heater is far from perfect, but it has sufficient positive attributes to merit consideration.

  • Impressive energy efficiency with 95% UEF
  • Stellar water heating performance with an FHR of 54 gallons
  • Recovers 21 gallons per hour at a 90-degree temperature rise
  • EverKleen self-cleaning technology for effortless maintenance
  • Exceptional lifespan with LifeGuard technology and tank lining
  • Hassle-free installation with built-in junction box
  • A bit pricey

What to Look for When Buying 40 Gallon Electric Water Heater


Buying a 40-gallon electric heater isn’t as confusing or intimidating as some folks want prospective buyers to believe. One only needs to check some water heater attributes or elements to decide which option to bring home.

  • Uniform Energy Factor

The US Department of Energy describes Uniform Energy Factor as a critical parameter of water heater efficiency or how well the appliance heats the water while consuming the least possible energy.

Water heater efficiency is directly proportional to UEF value (the more efficient the water heater, the higher its UEF score).

You can check the 40-gallon electric water heater’s UEF value on its “Energy Guide” label. You can always find the information on the manufacturer’s website if it’s unavailable elsewhere.

The most efficient 40-gallon electric water heater has a UEF value of at least 90% or 0.90.


  • First Hour Rating

Consumer Reports identifies a storage tank-type water heater’s First Hour Rating as a crucial consideration. This attribute describes how much hot water the appliance can deliver per hour after filling up. You can also see this value on the water heater’s Energy Guide label.

Like UEF values, aspiring buyers must check a water heater’s FHR score and choose the one with the highest value.

For example, suppose you have water heater A with a 55-gallon FHR and water heater B with a 60-gallon FHR. Although both are 40-gallon units, you’ll enjoy more and longer showers with option B.

This 40-gallon water heater should be more suitable for large family hot water activities than water heater A.


  • Recovery Rate

Although this parameter is nearly identical to a water heater’s FHR, the recovery rate reflects the appliance’s ability to “reheat” the water within an hour of continuous hot water use.

You can determine your ideal water heater recovery rate by multiplying 2.42 by the expected temperature rise. Next, divide the water heater’s wattage by the product obtained from the preceding multiplication.

For example, suppose you have a 4500-watt 40-gallon electric water heater, and you want to heat 60-degree water to 130 degrees. Multiplying 2.42 by 70 degrees (130-60=70) gives us 169.4. Dividing 4500 watts by 169.4 gives us 25.56 or 26 gallons.

You might want to check your average temperature rise (temperature difference between cold and hot water) to determine the minimum recovery rate your ideal electric water heater must have.


  • Tank Insulation

Although gas water heaters are more susceptible to standby heat losses, electric versions can also lose as much as 1400 watt-hours of heat (gas water heaters lose up to 8300 watt-hours). Hence, storage tank water heaters must have exceptional insulation to minimize heat losses.

Choosing a 40-gallon electric water heater requires checking its insulation capabilities. Most products feature foam insulation, while some integrate fiberglass or proprietary technology. Ideally, electric water heaters must have insulating materials with an R-value of at least R-22.


  • Maintenance Requirements

The true cost of 40 gallon electric water heater units reflects their purchase price and ongoing operational and maintenance. Unfortunately, water heater brands vary in maintenance requirements.

Buyers must be diligent in researching their prospective water heater’s upkeep requirements. You can read consumer reviews or post queries on internet community forums.

Other Important Factors to Consider

If you’re still unsure about what 40-gallon electric water heater to buy, factoring in the following considerations should help you narrow your selection.

  • Physical Dimensions

Although 40-gallon electric water heaters hold the same water volume, brands and models might vary in their physical dimensions. Some water heaters are tall and slender, while others are short and stout.

Buyers might want to measure the floor area where they intend to install the 40-gallon electric water heater, including its vertical space. Use the measurements to guide you in buying the correct unit that will fit into the earmarked space.


  • Guarantee

A 40-gallon electric water heater with a limited lifetime warranty is better than a similarly-sized unit with only a five- to ten-year guarantee. Although some buyers don’t consider this an essential factor, product coverage underscores a company’s belief in the quality of its offering.


  • Protective Technology

Corrosion and limescale buildup are the principal enemies of storage tank-type water heaters, and a 40-gallon unit isn’t immune to these problems.

You might want to check the electric water heater’s protective technologies (i.e., anti-scale devices, glass lining, proprietary anode rods, and more). Although these innovations look impressive, buyers must research the veracity of the company’s claims about the performance of these systems.


  • Price

Although 40-gallon electric water heaters are more affordable than similarly-sized gas-powered versions, purchase price varies across brands and models.

Buyers should consider a 40-gallon electric water heater’s best price relative to its water heating performance and other attributes or features mentioned in this buying guide.

What is a 40-gallon Electric Water Heater? How Does it Work?


A 40-gallon electric water heater is an appliance comprising a 40-gallon-capacity water storage tank, heating elements, controls, safety valves, and other components to raise the water temperature in the tank.

Even the cheapest 40 gallon electric water heater has similar elements, albeit at a lower quality to minimize cost.

  • The hot water storage tank features a dip tube, conveying cold water from the house’s main waterline to the tank’s bottom, filling it with water.
  • The water heater’s lower heating element draws power from a dedicated electrical circuit, slowly heating the liquid in that section.
  • As the water fills and reaches the tank’s top, the upper heating element continues raising the water temperature to the desired level.
  • A thermostat controls how many degrees the water should be heated. It adjusts power to the heating elements depending on the prevailing water temperature.
  • Hot water flows through the water heater tank’s outlet valve when someone hits the shower, washes the dishes or clothes, or uses any hot water faucet in the house. Cold water enters the storage tank through the inlet valve to replenish the used water.

Aspiring owners must realize that pressure can build up in heater tanks with increased temperature. Hence, these appliances feature a Temperature & Pressure (T&P) relief valve. It’s a safety device that lowers intra-tank pressure before the water heater explodes.

An issue with electric hot water heater units is their energy efficiency. Although cheaper than gas versions, electric water heaters tend to heat the water twice as long as gas water heaters.

For instance, a gas unit might heat the water in 30 minutes, while an electric version will accomplish the task in an hour. This water heating time variance can lead to higher energy costs.

As for the hot water storage tank, manufacturers continue to develop better technologies to optimize heating performance, minimize standby heat losses, and mitigate energy dependency. Advanced insulation and anode rods also protect the storage unit.

Why Do You Need 40 Gallon Electric Water Heater?

A 40-gallon electric water heater isn’t for everyone. Ideally, it’s best suited for a family of four. However, this still depends on the household’s hot water consumption.

Forty-gallon electric water heaters are also more straightforward to install and operate, requiring no ventilation and extensive maintenance. It can also be energy efficient if you pick a high-efficiency unit. These attributes make it a cost-effective water-heating solution.


How long does a 40-gallon electric water heater take to heat up?

A 40-gallon electric water heater needs about an hour to 80 minutes to raise the water temperature to your preferred level. However, the heating period depends on the water heater’s First Hour Rating and temperature rise.

It’s worth noting that electric water heaters take longer to heat the water than gas versions. For instance, a Whirlpool 40 gallon gas water heater might only need 30 to 40 minutes to bring hot water to your shower while an electric unit may require an hour or more.

How long does a 40-gallon electric water heater last?

Top rated electric water heaters can serve families for a decade, with some brands potentially lasting up to 15 years or more. However, even budget-friendly units can last ten years with frequent and regular professional servicing, including tank draining, cleaning, and flushing.

How many showers can you take with a 40 gallon electric water heater?

How many showers you can take with a 40-gallon electric water heater depends on how much water you use to shower, your home’s water flow rate, how long you bathe, and whether other appliances use hot water simultaneously as you shower.

For example, some folks only shower for 5 – 10 minutes, while others might spend up to 20 minutes in the bathroom. We can expect the former to have at least four showers per hour, while the latter might only be able to have two.

High-flow showerheads can use ten gallons more hot water for every 10 minutes spent in the shower than a low-flow unit. Hence, this can also impact shower frequency because you’ll use more hot water.

The Energy Department says a shower consumes ten gallons of hot water. If someone simultaneously uses hot water (i.e., dishwasher, washing machine, or kitchen hot water tap), you’ll have less frequent showers per hour.


The best 40 gallon electric water heater has a Uniform Energy Factor value of at least 90%, a high First Hour Rating, and an equally impressive recovery rate. Its insulating technologies also minimize standby heat losses, allowing families of three to four to optimize their water heating.

Of course, you can consider other factors. But if you don’t want to experience the hassle of nitpicking through hundreds of potential candidates, starting with the three 40-gallon electric water heaters here is always a welcome option.

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