Electric Heat Pump Water Heaters
Review and Buying Tips

Selection of the best electric heat pump water heaters - review and buying tips. Who should purchase a heat pump for water heating? Find out how these electric water heaters, also known as hybrids, can be Energy Star compliant and perform with the energy efficiency at least twice as high as the conventional tank heaters.



Heating water with the electric heat pump water heaters is very efficient and economical where the Energy Star compliance brings more savings either from the utility company or government (when applicable).

The heat pumps use a straightforward process of extracting the heat from the air to pass it to water. Since they are not generating the heat but move the heat from one place to another, the energy factor (EF) and first-hour rating are significantly higher than the EF found on conventional water tank heaters.

They are also known as the eco-friendly hybrid water heaters since they combine two technologies; heat pumps and electric heating elements. Hybrid technology allows either individual or combined operation of both electrical heating elements and the heat pump.

Components that make a heat pump unique

Rheem heat pumpRheem hybrid

Heat pump water heaters are similar to the electric tank-type heaters. They have a storage tank to store hot water and the insulation to keep the heat inside the unit longer. The submerged anode rod protects the metal tank from corrosion. At the bottom there is a drain valve for easier maintenance and flushing and close to the top TPR valve is used as a safety element to protect the unit from extreme pressure and temperature.

Two heating elements with thermostats are there for supplemental water heating and temperature adjustment when the heat pump is operating with the low efficiency, which happens during the cold weather.

Now, the difference is found inside and on the top of the water heater, where several components; fan, compressor, evaporator, and condenser are making this technology unique.

Models such as Rheem, AO Smith or GE utilize the advanced monitoring with the electric circuit board and LED control panel with the touchpad buttons so you can easily change the temperature or efficiency setting, for example.

How does the heat pump work?

The fan located at the top of the water heater forces the warm room air across the evaporator coils where the liquid refrigerant vaporizes. The compressor increases the pressure and temperature of the gas/refrigerant, which goes through the condenser, turns back into liquid and exchanges the heat with the surrounding water. This is how this electric water heater increases its efficiency of over 200%. While it heats the water, the unit cools and dehumidifies the surrounding air as well.

Selecting tips

The following elements are what you should consider when choosing the best hybrid water heater for your home:

Capacity. It is important to take into calculation the size of the house, how many bathrooms there are and the size of the family. Usually, for the households with four members, a 50-gal unit is sufficient but depends on the first-hour rating and recovery rate. They are mostly available in sizes from 50 to 80 gallons.

Type. While this buying guide is for stand-alone or integrated models, you can still buy and install an add-on to an existing electric model.

Efficiency. If you want to save more, choose the heater with the highest energy factor.

Climate. Colder weather directly affects the efficiency of the heat pump. During those days the electric elements are the main source of heating.

Location. Make sure that the room for the heat pump installation is big enough for normal air circulation, servicing, and maintenance. Keep in mind that hybrids require at least 1000 cubic feet of space. It can use the outside or surrounding indoor air.

Brand. Choose the model from the reputable manufacturer, such as Rheem, AO Smith, Bosch, Stiebel Eltron… Make sure to contact the certified installers for the installation and safe work, so the manufacturer doesn’t void the warranty.

Warranty. The best models with the lifetime warranty include the storage tanks that made of the stainless steel, making them resistant to corrosion.

Heat pump vs. electric tank-type

  • Heat pumps are 2-3 times more efficient than the electric tank-type.
  • Hybrids rely on heat pump technology and electric heating elements as the backup. Electric models use only heating elements.
  • Hybrids are slow in producing heat but since they mostly have four operating modes, the recovery rate and efficiency vary.
  • Hybrids cost much more than electric. The 50-gal unit can easily cost over $1000, while the electric few hundred bucks only.
  • Hybrids are more advanced.

You can get more information about heat pumps vs. electric water heaters in this article.

Heat pumps vs. gas

  • Heat pumps are even more efficient than gas tank-type, whose efficiency can go as high as 70% (conventional type). This means more money in your pocket over the years.
  • The recovery rate is much higher on gas type.
  • The gas type heats water fast.
  • Gas models are cheaper.
  • Gas type can work even during the power outage or cold weather.
  • Heat pumps use advanced electronics; some have WiFi capability, usually come with the large LCD and at least four operating modes for enhanced comfort, flexibility, and convenience, while maximizing energy savings.

Where to use heat pumps

The best location for the installation is a room with a higher temperature, such as the attic or the utility room, where the furnace is installed. It is recommended for regions with the warm climate such as the southern part of US, or where the average temperature is between 40 F and 90 F. The efficiency increases when the temperature of the surrounding air goes up.

If used in colder areas, it must be installed indoor where the heating is supplemented with the heating elements. It is an excellent choice for new homes, or as the replacement for your old electric water heater, in the basement, garage or attic.

Popular models

Most of the manufacturers of HVAC equipment is making hybrid water heaters which can be different in what they offer. Below are the most popular:

Rheem heat pump PROPH50

Rheem heat pump PROPH50 is the 50-gal hybrid water heater that is coming with the ultra-high energy efficiency. According to the Rheem manufacturer, this unit can save more than $4000 in lifetime energy costs, and it pays for itself in less than two years. That’s what they say. According to the specs., the energy factor is 2.45 while Uniform Energy Factor (UEF) is 3.70, which is almost three times more than standard electric, or even more when compared to gas type. This allows Energy Star compliance for the unit.

For homes where more hot water is needed, the fact that the first-hour rating is 67 GPH might be helpful while selecting the right unit. Also, with the operating temperatures which are in the range from 37 F to 145 F, you will be able to utilize the unit more days in a year, even in colder climates.

For the convenience, enhance comfort and more savings, Rheem PROPH50 offers several operating modes, also providing more flexibility to users.

Rheem exclusive EcoNetConnect allows Wi-Fi connection, and by using the available mobile app, users can quickly get full control of the system remotely. Moreover, with the advanced electronics, diagnostics, control, and monitoring allows great flexibility and convenience for users.

The unit comes with the extended 10-year warranty.

AO Smith Voltex HPTU-50N

AO Smith Voltex HPTU-50N is another great 50-gal hybrid water heater that is designed to heat the water and at the same time dehumidify and cool the ambient air. As the above Rheem heat pumps, Voltex also comes with the 10-year warranty and high first-hour rating of 66 GPH.

By using one of the four operating modes, the user can set the unit to work with the highest efficiency which is 3.42, to get the fastest recovery or just put it in vacation mode for savings and protection from bacteria development or freezing, when away. As the above Rheem, Voltex is equipped with the two heating elements that have the dry-fire protection, sacrificial but heavy-duty anode rod that ensures better corrosion protection and longer life, and advanced electronics with the LCD.

GE GeoSpring

GE GeoSpring hybrid water heater GEH50DFEJSR uses both heat pump and electric technology for an efficient water heating. It uses the same connections for the fast and easy installation. It is similar to the electric unit, almost the same footprint, but is more advanced; it offers a cool control panel with the back-lit LCD, buttons to set the temperature and choose the operating mode.

Stiebel Eltron Accelera 220 E

What makes Stiebel Eltron Accelera 220 E different from the rest in this review is that this unit is not a hybrid, as explained by the manufacturer – the unit utilizes only the heat pump technology and doesn’t have heating elements as the backup. The reason is that they wanted to offer the most efficient option, so the unit doesn’t have to choose between different settings. In the case of the ultra-high demand for hot water, the Accelera can use the single booster element, located at the top of the unit.

The unit doesn’t have the “vacation” mode, when the user is away, and which is used to protect the unit from energy waste and freezing during winter time, while it relies on its super thick insulation. The energy factor is 3.05 (Energy Star), and the first-hour rating is 50.3 GPH.

As opposed to other heat pumps which are equipped with the heavy duty anodes, but still sacrificial, the Accelera comes with the electronic anode which allows maintenance-free protection.

The smallest model comes with the 58 gallons but is advertised as the 50-gal model.

Advantages of heat pumps

  • By installing a heat pump, instead of the conventional electric, the electric bills will be reduced by several hundred dollars annually.
  • Frequent incentives decrease the initial purchase and installation price.
  • The advanced control allows accuracy, savings, convenience, and enhanced comfort.
  • Wi-Fi capability for remote control and monitoring.
  • Advanced diagnostics for easier troubleshooting.

Disadvantages of heat pumps

  • Expensive if there are no incentives.
  • Need supplemental heat if installed in cold areas.
  • It needs sufficient air supply for the proper work.
  • Loud. The heat pump is often making a humming noise, similar to AC, which doesn’t make it suitable for installation close to the bedrooms.


Electric heat pumps for water heating are expensive but an excellent long-term investment due to its superior efficiency, and Energy Star compliance, which makes them eligible for tax breaks and other rebates. They are recommended for high demanding homes due to the high recovery rate and cost reduction of up to 80% on some models.

No matter whether you are planning to reduce the cost or environment impact, a heat pump water heater is a great choice. Due to its construction, they can easily replace the electric type and in some regions without the need for supplemental heating. Also, with the significant incentives offered by utility companies or the government, the cost of purchasing and installing heat pumps can be very affordable, even on par with the standard electric model.

Other types of heat pumps such as air-to-air, water-sourced and other can be found on heatpumpshq.com.


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