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Home > Water Heater Reviews > Electric Heat Pump Water Heater

Electric Heat Pump Water Heater

Residential water heating with heat pump water heaters. Installing tips...

Electric heat pump water heater system is an inexpensive way of water heating that uses electricity to extract heat from the air, move it from one place to another, for high efficient hot water production.

How Heat Pump Water Heater Works

Water heater heat pump (HPWH) is constructed to move the heat from one place to another, rather that heating the water directly.

It works similar as refrigerators or air conditioner, in reverse.

Water heater heat pump uses the standard principles of refrigeration to draw the heat from air by using the built-in fan and send it across the evaporator coil.

The heat from the air causes the refrigerant to vaporize which goes to the compressor where the refrigerant fluid further increases its temperature. The hot vapor from the refrigerant enters the condenser coil where it transfers its energy to the cooler surrounding water in the heat exchanger and the storage tank.

The electric heat pump water heater has more than twice the efficiency of conventional electric water heaters, and performs the best in warm climates while it cools and dehumidifies the surrounding air.

The efficiency depends on the surrounding air, incoming water temperature, heat transfer characteristics of the unit and losses within the system.

When buying the electric heat pump water heater use three parameters when comparing different models:

The heating coefficient of performance, COP, is used for the performance, and it defines the ratio of the energy of heat pump to the electrical energy unit.

Energy Factor or EF is the ratio of energy output to energy input. An average value for these pumps is between 2 and 2.5 (for reference; maximum EF for electric heater is close to 1).

The first hour rating.

Heat Pumps Water Heaters - Main Components

Fan
Compressor
Evaporator
Condenser
Insulation
TPR valve
Cold water inlet
Hot water outlet
Upper and lower thermostat
Drain
Anode rod

Heat Pump Water Heater Types

There are few types of heat pump water heaters available for you to buy:

An integral heat pump water heater comes as one package and features the pump connected to the storage tank with the back-up resistance heating elements. It has the same footprint and connections as the standard storage tank, and the installation is similar, except the requirement for the condensate drainage.

Add-on water heater heat pump, or retrofit units, is installed in conjunction with an existing heater, either on the top of the tank or wall-mounted. It replaces the function of the tank's lower heating element, being the main heat source. Small pump has to be installed between the tank and the pump to circulate the water.

There is also a geothermal heat pump that uses the energy from the ground during the winter and mainly for home heating. By adding a small heat exchanger, called desuperheater you can heat the water as well.

Installing Heat Pump Water Heater

Heat pumps do not generate the energy directly, and while they operate, they tend to cool the space they are in. This is the reason why to install these pumps in isolated locations but not in a cold space.

The best location for water heater heat pump installation are places where the average temperature is between 40 F and 90 F year-round, with the sufficient air available and where is the additional source of heat, like furnace rooms.

In colder climates they will be installed indoors and would provide cooling and dehumidification inside the room where it is located.

There is a tendency in colder areas that the ice builds up on the condensing coil. This is what causes the restriction in air flow and the damage in the internal components. Recommendation is to buy the pump with the "Defrost Mode" so you will never experience such operation problems.

You should consider installing a heat pump water heater if your home is a high-demand home and where the electricity and gas rates are high and gas is not available.

Heat Pump Water Heater Advantages

If using the gas heater to heat the pool it might be too expensive for you. Water heater heat pump is the best solution for the pool heating. Heat pump is very easy to install, it is reliable and efficient.

As mentioned before the HPWH provides an energy saving alternative to the electric heaters because less energy is needed to move heat than to create it.

Electric heat pump water heater models are the only electric heaters that qualify for a tax credit. In order to qualify, the pump has to have an energy factor, EF, at least 2.0 and minimum first hour rating of 50 gph. Look for the Energy Star label and you will be able to save up to 30% of the cost or up to $1,500 with the including installation and labor costs.

RHEEM 50G HP50RH

Our recommendation is to look at the Rheem manufacturer as it produces units with the ultra-efficient heat exchanger made of the Titanium. Specially designed heat exchanger helps in the reduction of deposit build-up also.

The GeoSpring electric heat pump water heater from GE as the Energy Star unit is also a good pick, featuring multiple settings including high demand and hybrid mode, electronic back-lit LCD display, flexible and easy-to-use electronic control panel.

Other popular heat pump manufacturers are: AirGenerate, Stiebel Eltron Accelera 300, E Tech by AO Smith, North Road Technologies, Sanyo, Hitachi, Toshiba...

Heat pump water heaters are good investment as they reduce the heating costs by as much as 50%. The only problem might be the initial high purchase and installation costs, where residential HPWHs are in a range from $600 to $2000 and installation from $300 to $700.

Related articles

Rheem heat pump review
Ruud review
GE GeoSpring
AO Smith Voltex

Picture is courtesy of energysavers.gov

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