Water Heating Systems

Today’s water heating technologies offer reliable, cost-effective solutions that can meet your facility’s unique needs.  Georgia Power invites you to explore the wide range of water heating solutions available to you.

Heat Pump Water Heaters (HPWH)

Get free cooling as you fulfill your hot water needs

Does your facility have hot, humid areas like kitchens or laundries that need cooling? Would you like to reduce your costs for producing hot water? If so, consider switching to a heat pump water heater, which can provide free cooling while it produces hot water—all at a fraction of the cost of conventional water heaters.

Our efficiency consultants have worked with customers in a wide number of industries, helping them analyze their operations and estimate the savings they can realize using this technology. Check out the cost savings information in the table below and then compare it to the needs in your facility. If you think this type of equipment is for you, contact us and we’ll work with you to explore it further.

The cooling units associated with a heat pump water heater can be located to provide welcome cooling and dehumidification in just the spots you need. Several types are available that can also provide constant cooling.

Besides saving hot water heating costs, the fresher, drier work areas mean a more comfortable staff and cooler operating equipment.

Significant Savings

The chart below gives estimated installation costs, operating costs and savings of heat pump water heaters over conventional gas systems.

The chart below gives estimated installation costs, operating costs and savings of heat pump water heaters over conventional gas systems.

Gallons Per Day

  500 1000 2000
Heat Pump Water Heater Tons / Cost 1.5 / $5760 5 / $12,740 10 / $23,740
Operating Cost Per Year $590 $1180 $2360
Water Heating Savings Plus A/C Value $1904 $3807 $7615
Simple Payback 2.7 yr. 1.8 yr. 1.5 yr.

*Typical water use for kitchens 1.8 -2 gallons of hot water per meal served

Heat Pump Water Heater Basics

The best way to understand the basic operation of a heat pump water heater (HPWH), is to think of it as a “black box”, without considering the inner workings. Using this approach, the figure below illustrates the three energy flows involved with a typical HPWH.

Heat Pump Water Heater Energy Flow

The HPWH makes hot water by removing heat from the heat source, producing a cooling effect. Air-source HPWH, the eat source is usually warm, humid interior air.

HPWHs use a small amount of electricity to upgrade the temperature of the heated water to achieve the desired temperature. The water heating efficiency of a heat pump water heater is always greater than 100%, and usually substantially greater (two to four times). In addition to the water heating output, HPWHs can provide a useful cooling and dehumidification effect with no additional energy input.

The electric energy input results in two useful effects: cooling and heating. The heating output (electrical input + heat removed from the heat source) is applied toward a water heating load. The cooling output is often used to cool and dehumidify the interior of a building. Since HPWHs have efficiencies greater than 100%, water heating efficiency for a HPWH is described by the Coefficient of Performance (COP), instead of using the term “efficiency.” The water heating COP is the ratio of the useful water heating output to the electric energy input.

It typically achieves a maximum temperature of about 130-150°F depending on the refrigerant used. While heating water, the HPWH also provides a cooling effect of about 6700 BTUH per kilowatt.

The fundamental principles of operation for a HPWH are the same as those of a room air conditioner or a refrigerator. The basic functional components of a heat pump water heater are the evaporator, compressor, condenser, and expansion device.

Heat is transferred by the flow of refrigerant, taking advantage of the large amount of heat absorbed and released when the refrigerant evaporates and condenses. The flow of refrigerant is caused by the pressure differential created by the compressor. The compressor and condenser operate at higher pressure, so that portion of the refrigeration system is called the high side. The portion containing the evaporator and the expansion device is called the low side. The compressor pulls refrigerant from the evaporator on the low side and discharges it to the condenser on the high side, much like a pump lifting water uphill. The expansion device resists the flow of refrigerant back to the low side, maintaining the pressure differential.

HPWH with a tank

Somewhat more efficient than their tankless counterparts, HPWH’s with water storage tanks boast annual coefficients of performance ranging from 3.0 to 4.0. These units must either replace or be connected in series with an existing water heater.

HPWH with double ducting for airflow

Ideal for tightly constructed buildings, an HPWH with double ducting for airflow can simultaneously heat water and achieve air-to-air heat exchange for ventilation. They are similar to single-ducted units but have two sets of ducting connections and two fans for forcing air through ducting.

HPWH with single ducting for airflow manipulation (tank or tankless)

A multi-function, energy-saving design, HPWH with single ducting for airflow manipulation (tank or tankless) includes a ducting connection and a fan capable of forcing air through the ducting. Such units are useful for moving cool, dehumidified air from the heat pump into areas where cooling is desired, or away from areas where cooling is not desired. Alternatively, the ducting can supply the heat pump with higher-temperature air to achieve better water heating performance or remove heat from unconditioned areas such as attics. If ducting is routed to the outdoors, the units can assist in building ventilation as well.

HPWH without a tank

HPHW’s without a tank are highly efficient—annual coefficients of performance range from 2.0 to 3.0, which means they consume one-half to one-third as much electricity as electric resistance units. Air-source vapor compression heat pumps, these units are specifically designed to heat domestic water and to be connected to a conventional water heater tank. Such units can be retrofit to existing water heaters.


A spa HPWH is similar to a swimming pool HPWH but is designed to heat water to higher temperatures, typically 110 to 120ºF.

Swimming pool HPWH

For a swimming pool HPWH, the swimming pool serves as a tank. Unlike units designed to heat potable water, these water heaters are constructed of materials capable of withstanding exposure to typical swimming pool chemicals. Since most swimming pools are heated to less than 90º, the equipment is optimized for better low-temperature performance.

Water-to-water HPWH

A water-to-water HPWH is a vapor compression device that utilizes water instead of air as the heat source. This type of system is found mostly in commercial applications for utilizing waste heat in cooling-tower water circuits. Variations exist for use with other types of water loops, such as ground-coupled heat exchangers. Both residential and commercial equipment is available.