AO Smith Heat Pump Review
Voltex PHPT-80 and SHPT-50

AO Smith Voltex heat pump

An expert review of the AO Smith heat pump Voltex. Find out important details about Voltex, also known as the hybrid water heater, with its features, pros, and cons and how this technology can save you money.

Voltex is the hybrid electric water heater that utilizes the heating elements and the heat pump technology to increase the recovery rate and energy efficiency while cutting the energy usage by half. Saving energy in water heating means more money in your pocket.

Models review

AO Smith heat pumps from Voltex series can be found in two sizes: larger PHPT-80 with the 80 gallons’ tank capacity and SHPT-50, equipped with the 50-gallon tank. If your family requires lots of hot water, a high capacity model will provide enough hot water for the peak demand periods.

AO Smith Voltex Electric Heat Pump - model PHPT-80

Voltex PHPT-80 is the high-capacity heat pump which is a larger model (82" in height, 25” in diameter) than the 50-gal unit, (63" in height and 22" in diameter).

PHPT-80 is also a more advanced unit, as it utilizes the LCD touchpad control with the intuitive icons and power anode for superior corrosion protection and longevity of the metal tank.

While the PHPT-80 comes with the sizable 80-gal tank size, its energy factor is lower than the 50-gal model - it is 2.33 when running in hybrid mode, which is still much higher than the electric models, and is also qualified for Energy Star.

AO Smith Voltex Electric Heat Pump - model SHPT-50

Model SHPT-50 is the heat pump with the 50-gallon tank capacity, and it comes with the ultra high energy factor of 2.78. Another noticeable difference between SHPT and PHPT heat pumps is in the user interface.

Both controls are easy to use, have buttons for easy adjustment, but the PHPT-80 model has a larger LCD screen with the status icons that indicate the operating mode, safety lock feature, efficiency and heat source indicators.

The SHPT model utilizes the LED diodes that signalize the mode setting and the communicating port for the remote control with the smartphone, for example.

Both 50 and 80-gallon models come with the 10-year warranty for the water heater tank and its parts.

Great benefits when using AO Smith heat pump

Voltex, as other heat pump water heaters, uses the surrounding warm air to pre-heat the incoming water, and compressor to increase the water temperature while dehumidifying and cooling the air at the same time. Voltex uses the same cooling/heating principle as your refrigerator or air conditioning unit, and it requires lots of fresh air. This is why the installation inside of the smaller rooms or closet is not recommended.

AO Smith heat pump is also an electric water heater that uses a standard voltage of 240 V and two heating elements, upper 4,5 kW, and lower 2 kW. Yes, Voltex is an electric heater that provides the same amount of hot water as the conventional electric unit and has the same capacity, but with over two times the efficiency.

Voltex heat pumps are also Energy Star compliant due to the hybrid technology and its insulation thickness of 2", which makes it eligible for federal tax credit, rebates and incentive programs. All the above advantages, together with the environment-friendly R134a refrigerant, makes this unit versatile and "green."

Operating Modes

AO Smith heat pump runs in one of the four modes so your heating requirements can adjust according to the outside conditions. This allows the use most of the year, either using separate operations or combined.

  • High efficiency
  • Hybrid
  • Electric
  • Vacation mode

High-efficiency mode draws the heat from the surrounding air and transfers it to the water through the heat exchanger. This mode also allows your hybrid water heater to revert automatically to the heating element if the temperature of surrounding air or water is not optimal for heat pump operation (below 45 F or above 109 F). When Voltex is working in this mode, it can reach energy efficiency of up to 2.78 for the 50-gallon model and 2.3 EF for the 80-gallon water heater.

Hybrid mode, based on the heating requirements, allows the water heater automatically to switch between the compressor and heat elements for the maximum efficiency. This is the default mode that uses the heat pump as the primary source for water heating, while the electric heating elements will turn on if there is a need (high demand). When Voltex operates in the hybrid mode its first-hour rating is the highest; 68 GPH for the 50-gallon model and 84 GPH for the 80-gallon water heater.

Electric mode uses heating elements only, where your Voltex works as the electric water heater. The recommendation is to use this mode during the winter, cold days.

Vacation mode is a great feature when you are absent as it helps you reduce the operating cost and prevent the unit from freezing during the winter time. By switching to the vacation mode, the water heater will maintain the temperature of water of approximately 60 F.

AO Smith heat pump can produce hot water with the temperatures from 95 F to 150 F, which can be adjusted using up and down buttons on the front panel.

Voltex top features

The heat pump is integrated into the top of the Voltex. High capacity tanks, enable the heat pump to operate more frequently than the heating elements. Correct condensate draining and the minimum amount of air will guarantee the proper work.

As explained before, the heat pumps are equipped with the advanced electronics that allow easy control and monitoring, while displaying the error messages if there is a problem with the unit, making the troubleshooting process simpler. Dry fire protection prevents failure of the heating elements when the water tank is not full of water.

The powered anode rod that is found on PHPT-80 unit is known as the non-sacrificial anode rod as it does not deteriorate over time. It protects the tank from corrosion longer, requires less maintenance and eliminates the need for anode replacement, so the smelly and discolored water are not problems anymore.


AO Smith heat pump is one of the latest advancements in water heating industry and a great addition to an already wide selection of AO Smith heating appliances.

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