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Energy Efficient and Reliable

Commercial Heat Pump

40-119 Gallon
Long Lasting
Superior Performance

The Vaughn Heat Pump Water Heater combines the proven longevity of a HydraStone lining and steel construction with Vaughn's efficient heat pump technology. With three inches of high-quality, CFC-free foam insulation, the Vaughn Heat Pump Water Heater has the lowest standby heat-loss rating in the industry. A streamlined user interface on the controller ensures ease of use and is highly versatile, including a customizable temperature differential, temporary mode overrides, and child lock protection. A high level of efficiency ensures a fast payback period, and the long life of the Vaughn HydraStone lined tank ensures additional long-term savings. Suitable for even the coldest of climates.


The Energy Star Rated MK II Electric Heat Pump Water Heater

Featuring all the same affordable, low-maintenance, and durability features as our heat pump water heater, Vaughn is now offering the MK II Electric Heat Pump Water Heater, with Energy Star 5.0 ratings. The Energy Star 5.0 certification opens up opportunities for tax write-offs and incentives in many states, ensuring a worthy investment.

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  • Simple Operation - Fully integrated water heater easily replaces a standard electric water heater
  • User-friendly electronic controller simplifies operation, maintenance, and troubleshooting
  • Low maintenance design - Designed for simple installation and service by a professional plumber
  • HydraStone lining ensures long tank life
  • Proven heat pump technology - Incoloy sheathed backup electric elements resist corrosion and mineral build-up
  • Heavy Duty Construction - Thick gauge carbon steel storage vessel with 1/2" seamless HydraStone lining
  • Insulated with 3" of CFC-free polyurethane foam insulation to minimize heat loss
  • No Sacrificial Anode Rod - Reduces operation expenses by eliminating periodic inspection and replacement costs associated with maintaining an anode rod
  • Warranty 10-year limited tank warranty

Additional Product Details

How the Vaughn Heat Pump Water Heater Works

The Vaughn Heat Pump Water Heater uses a small amount of electricity to transfer heat to the water from the surrounding air. In comparison, traditional electric water heaters use resistive heating elements to directly heat the water. The Vaughn Heat Pump Water Heater is significantly more energy efficient when compared to a conventional electric water heater because the heat pump utilizes considerably less electricity than a standard electric unit. In essence, a heat pump works like a refrigerator in reverse. A refrigerator moves heat from inside the refrigerator (making things cold) and transfers that heat energy to the surrounding room, whereas a heat pump water heater captures free and essentially unlimited heat from the ambient air and transfers that heat to the water stored in the tank. The Vaughn Heat Pump Water Heater can capture heat from air as cool as 40°F. If the unit cannot provide enough heating capacity to meet the demand, the backup resistive heating elements will activate to ensure the unit provides sufficient hot water. The process of removing heat from the air and transferring it to the water results in the exhaust of cooler dryer air. This added benefit of dehumidifying the surrounding air can provide as much as 0.4 gallons per hour of "free" dehumidification provided by the heat pump unit is heating water.

Heat Pump Functions

  1. The built-in fan draws room air into the water heater heat pump compartment and across an evaporator coil, and exhausts cooler and slightly dryer (dehumidified) air.
  2. The evaporator coil captures heat energy in the air and transfers that energy to a specially formulated CFC-free refrigerant contained within the evaporator.
  3. The refrigerant changes from a liquid to a gas as it gets warmer.
  4. The refrigerant, now as a warm gas, exits the evaporator and passes into a compressor.
  5. The warm gas is compressed, causing it to become a superheated hot gas and then flows to the heat exchanger.
  6. The heat exchanger transfers heat energy from the superheated hot gas to the cold water from the tank.
  7. The pump circulates cold water from the tank through the heat exchanger resulting in a continuous transfer of heat energy from the superheated gas to the water.
  8. Hot water exits the heat exchanger and is stored in the tank.
  9. The superheated gas condenses back to a liquid and awaits to repeat the process.
Heat Pump
Heat Pump

Selectable Operating Modes

  • Economy: This mode controls the heater such that the heat pump provides essentially all of the heating capacity. This is typically the lowest operating cost mode.
  • Hybrid: This mode controls the heater in a way to optimize its efficiency and user experience and is the default setting. This mode operates the water heater such that the heat pump provides the vast majority of heating capacity and automatically switches to electric resistance heater mode only when necessary to meet high demand or to optimize efficiency.
  • Electric: This mode controls the heater such that it only heats using the electric resistance heaters and operates as a traditional electric water heater. The heat pump will not operate in this mode.
  • Super: This mode controls the heater such that both the heat pump and the electric resistance elements can operate simultaneously. This mode provides the fastest recovery option possible by providing heating capacity from both the heat pump and the electric resistance heaters at the same time.
  • Vacation: This mode prevents the heater from heating (regardless of what mode it is in) as a way to improve efficiency during long periods of no usage (i.e. vacation). In this mode, the only time the heater will heat is if the unit is in danger of freezing. The user sets the number of days to be in vacation mode (adjustable from 2 to 99 days or Off), and the unit resumes its previous mode of operation at the end of this period.



Temporary Modes

  • Max Heat: Simply pressing one button maximizes heating capacity by temporarily putting the heater into super mode.
  • Fan Off: Simply pressing one button temporarily lowers the fan speed which reduces the airflow and minimizes operating noise. Pressing the button twice turns the fan off for a user adjustable time period.

Dimensional Data

Storage Capacity (Gallons) Part Number Dimensions (Inches) Shipping Weight (lbs.)
Overall Diameter Overall Height Floor to T&P and HW Outlet Floor to CW Inlet
50 S50WHPT3838I 25 66 43 9 475
65 S65WHPT3838I 28 63 40 9 525
80 S80WHPT3838I 28 73.5 50 9 575
119 S120WHPT3838I 30 84 61 9 680

Note: These units are designed to meet or exceed ANSI (American National Standards Institute) requirements and have been tested according to D.O.E. test procedures and meet or exceed the energy efficiency requirements of NAECA, ASHRAE standard 90, ICC Code and all state energy efficiency performance criteria for energy consuming appliances. 

Heat Pump Outline Dimensions Diagram

Installation Requirements

  • Installed location must be at least a 10' x 10' x 7' room (700 cubic feet of air space). If smaller, there must be a louver installed to provide sufficient airflow.
  • Installed room location must not be cooler than 40°F.
  • Installed locations with warmer ambient air temperature (i.e. furnace room) provides abundant "free" heat and are advantageous.
  • The heat pump dehumidifies the air and as a result, produces condensate which must be piped to drain or outdoors.
  • The washable air filter requires periodic cleaning. Frequency depends upon environmental conditions.

Energy Consumption Chart

Annual Energy Consumption (EST)
Air Temp
Coefficient of Performance (COP) Annual Energy Consumption and Operating Cost in Various Operating Modes
Economy Hybrid Electric Super
kW·Hrs Operating Cost $ kW·Hrs Operating Cost $ kW·Hrs Operating Cost $ kW·Hrs Operating Cost $
50°F 1.6 2950 $314 2950 $314 4671 $497 4289 $457
70°F 2.6 1759 $187 1759 $187 4671 $497 3733 $398
90°F 3.4 1350 $144 1350 $144 4671 $497 3404 $362

Note: Average Annual Operating Costs based on 2007 D.O.E. (Department of Energy) test procedures. D.O.E. national average fuel rate electricity 10.65¢/KWH. 

  • 1 1/2" Male NPT inlet and outlet water connections
  • Tank installed heat exchanger for use with solar or radiant heating systems (3/4" or 1" diameter)
  • Alternate voltages (1 or 3 phase), alternate wattages or 50 Hz available

Hybrid Heat Pump Specific Questions

Unlike standard electric water heaters, heat pump water heaters use an air filter. These filters need to be cleaned to ensure efficient operation. In addition, a HPWH generates condensate which must be plumbed to a proper drain.  This condensate drain may be gravity or pump assisted, and in both cases needs to be periodically inspected and cleaned to ensure proper drainage.  Other maintenance needs are similar to standard electric water heaters.
HPWH’s are the latest technology in water heating and provide the highest efficiency available for heating water.  As a comparison, the Vaughn high efficiency 50 gallon electric water heater is estimated to cost $508 per year to operate, whereas the Vaughn model WHPT heat pump water heater is estimated to cost $201 per year, a savings of $307 annually.  So, from an operating cost standpoint, the advantage of a HPWH is clear.  However, other factors need to be considered when deciding HPWH versus electric water heater.  One major factor is the initial total installed cost of the heater, with a heat pump water heater approximately 2-3 times higher cost compared to a traditional electric water heater.  Compared to a standard electric water heater a HPWH is a more challenging and therefore more expensive installation, has more restrictions with respect to installation conditions and is newer technology and therefore to a certain degree less proven and more challenging to service.  Having said that, a HPWH is by far the most efficient method for heating water and deserves careful consideration if it is right for your application.
When selecting a heat pump water heater model it is important to take your climate into consideration. Some climates experience freezing temperatures; water heaters installed in these climates in unheated locations require protection from freezing and other additional safety and performance features. The Northern Climate Specification Qualified Products List will help you find the right heat pump water heater for your location, for details click here Here and clicking on your state.
These terms are interchangeable and refer to the same type of heater.  The term “Hybrid” arose when manufacturer’s combined standard type electric water heaters with a heat pump to create a new type of water heater.  This new type of water heater includes both electric resistance heating and heat pump technologies, and therefore the term Hybrid water heater was coined.  However, the marketplace is also calling this new type of water heater a Heat Pump Water Heater even though it includes resistance heaters.  The only time when a heat pump water heater would not be considered a hybrid is if it did not include any form of electric resistance heater.  The Vaughn model WHPT water heater is comprised of both resistance heaters and a heat pump system, and therefore is considered a hybrid, although as noted above is also referred to simply as a heat pump water heater.
Check our rebates and tax credits page at Here for a list of available rebates and tax credits before installing a new heat pump water heater. There may be financial incentives offered by local, state or federal government and/or your local utility. By visiting Database of State Incentives for Renewables & Efficiency Here and clicking on your state, you may find available rebates and incentives.
Heat pump water heaters can be installed in a variety of locations, from a garage to a heated utility room. Things to consider include space, sound, cold air, and size/height. For more information, visit Here.
It depends on which operating mode the HPWH is set to.  There are a total of five (5) operating modes available:  Economy, Hybrid, Electric, Super and Vacation.  The Vaughn HPWH makes no sound when in Electric or Vacation mode.  If Economy, Hybrid or Super mode is selected the Vaughn HPWH will make noise as the fan operates and pulls air through the heat pump.  If the Vaughn HPWH electronic controller detects any fault condition it will make a beeping sound and display an error code.
Cold air will blow from the water heater any time it is operating utilizing the heat pump.  The heat pump works by using a small amount of the heat from the surrounding air to heat the water in the tank. The by-product of the heat pump system is cold air, the warm air is pulled through the system fan to heat the water, then the remaining cooler air is moved out the side of the heater.
You can temporarily stop the cold air and fan noise coming from the water heater by pressing the FAN OFF button.  During this period of time the water heater will operate in Electric mode, thereby preventing the fan from operating.  You can adjust the length of time this feature.
The Energy Factor (EF) rating represents the efficiency of the water heater. The higher the EF, the more efficient the water heater unit. The Vaughn Model WHPT heat pump water heaters are classified by the Department of Energy as residential water heaters and are rated by an Energy Factor (EF) ranging from 2.2 to 2.35 depending upon the model size you select. Please note that the use of R values as a measure of efficiency is incomplete and does therefore does not accurately capture a water heater’s true efficiency as does the EF rating. For additional information check out the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) website at Here as well as the American Council for an Energy Efficient Economy (ACEEE) website at Here
The heat pump removes a small amount of heat from the surrounding air, heats the water and moves the cooler air back into the room. The Vaughn model WHPT Heat Pump Water Heater produces the same amount of hot water as a traditional electric water heater, but with greater efficiency. Think of the HPWH as a refrigerator working in reverse. Just as a refrigerator removes heat from its enclosed interior and releases the heat into the surrounding kitchen, a HPWH takes heat from the surrounding air and transfers that heat into the water of the tank. These things are normal with a Vaughn HPWH: It is normal for cool air to blow out the vents on the back cover of the water heater. The air is moved through the water heater by a fan located within the heat pump enclosure on the top of the water heater. You will hear the sound of this fan pulling the air through the heat pump system. As the water heater determines the right amount of energy needed to heat the water the fans will change speed and the sound will increase and decrease. For a detailed discussion regarding HPWH’s please go Here.
Vaughn Model S and ME water heaters with 30 gallon storage or more have both upper and lower heating elements in the tank, and models 20 gallon storage and less have one heating element in the tank.  The purpose of having two heating elementsis to improve the recovery rating in a water heater of significant storage capacity. Sometimes referred to as a “Quick Recovery” water heater, this configuration allows the upper element to heat a much smaller volume of water (about 25% of the tank's capacity) before the lower element takes over. This provides a small amount of usable hot water quickly while you wait for the bulk of the water to heat.  It is worth noting that in the standard dual element design, the upper and lower heating elements are interlocked so that only one can heat at any time, with priority to the upper element.  Once the thermostat controlling the upper element is satisfied (i.e. at set point temperature) the lower element is allowed to heat.  As an option, you may order your Vaughn water heater with the optional “simultaneous operation” feature which allows each element to operate independently, potentially allowing both to be on at the same time in order to increase the recovery rate of the heater.
The most important factor related to the life expectancy of a water heater is the quality and type of storage tank.  On an average the life expectancy of a glass lined electric water heater is about 10-12 years (according to the National Association of Home Builders 2007 Study of Life Expectancy of Home Components ), compared to a cement lined electric water heater’s average life expectancy of 23-26 years (Independent study of over 25,000 installations for an Electric Utility).  Of course, there are various other factors that affect longevity including pressure fluctuations, usage, water conditions, environmental conditions, etc.
Water heater timers are devices that provide automatic control of electric water heaters. They can be programmed to turn a water heater off or on at times typically set by your local utility.  Your local electric utility may have in place an “Off-Peak” or Time-of-Use (TOU) rates which offer a customer the incentive to consume power during certain periods of the day.  The Vaughn S and ME Models are available with various timer control options, ranging from programmable 7 day timers to utility specific devices that control the water heater.
The Vaughn water heater is constructed with a heat trap installed within the water heater’s hot water outlet connection.  This device helps prevent heat from escaping through the storage tank’s hot water outlet during standby periods, resulting in improved operating efficiency.  The heat trap is constructed from a specially designed bronze nipple with an internal floating ball that during standby periods of no flow settles and closes off the storage tank thereby preventing thermal conduction of hot water radiating through the hot water outlet.
All water heaters constructed using a steel tank requires a lining to protect the internal steel surfaces from corrosion.  Certain linings (i.e. glass and epoxy), due to their nature, have unavoidable holes and imperfections resulting in exposure of the steel tank.   As a result of this deficiency, the manufacturer will install an anode rod(s) in an attempt to delay corrosion of the steel tank.  An anode rod is typically made of aluminum, magnesium or zinc, is a maintenance item that requires periodic inspection and replacement, and is often times the cause of a “rotten egg” odor to your hot water.  Often referred to as a sacrificial anode rod because, over time, it slowly dissolves, sacrificing itself as it is attacked by aggressive substances in the water which would otherwise attack the steel tank through the pinholes and imperfections of the glass or epoxy lining.  A cement lined steel tank on the other hand does not require an anode because of the thickness and guaranteed 100% coverage of the cement lining over all internal surfaces of the steel tank.  This eliminates the need for an anode rod in a cement lined water heater, resulting in a significantly longer life compared to a glass or epoxy lined water heater.
It depends.  The Uniform Plumbing Code (UPC), section 510.5 states In seismic zones 3 and 4 water heaters shall be anchored or strapped to resist horizontal displacement due to earthquake motion. Strapping shall be at points within the upper one-third (1/3) and lower one-third (1/3) of its vertical dimensions. At the lower point a minimum of four (4) inches (102mm) shall be maintained above the controls with the strapping."  If the installed location is in these seismic zones then a strap/restraint system is required.  Otherwise please consult with a plumbing engineer to determine the proper installation method for your water heater.
Yes, Vaughn advises that a drip pan with a proper drainage connection be installed under your water heater.   In some locations drip pans are required by code and in other situations they are highly recommended, but not required.  In either case, if a water heater leak or a dripping relief valve could result in property damage then a drip pan must be installed under the water heater, even when not required by code.
Vaughn uses a blown-in polyurethane foam insulation for all cement lined water heaters and tanks up to 120 gallon capacity. This insulation has an R value of 7.2 per inch. Most Vaughn tanks have a minimum of 2 inches of insulation resulting in an R value of 14. Certain models are available either standard or as an option with 3 inch insulation and therefore have an R value of 21.
The water heater must be stored in the orientation of intended use (vertical, horizontal). The recommended ambient air temperature range is between 50 and 105 degree F and not exceeding 65% Rh. Under no conditions should the unit be subject to freezing temperatures. The unit is intended to be stored indoors, protected from the elements. Desiccant material should be inserted into the electric control panel and heating element terminal house (if applicable). Prolonged storage will require periodic inspection of desiccant. For cement lined tanks only, place approximately 10 gallons of water in the tank before closing and sealing all openings to ensure a humid atmosphere for the lining is maintained. Cap and seal all openings and tank tappings and/or flanges. Provide the necessary protection to ensure the tank and all accessories are protected from physical contact that could result in damage. Shrink wrapping or other suitable protective plastic may be applied to the exterior. Start up and installation guidelines must be followed, with particular attention to testing of the electric heating element.
The HydraStone lining provides guaranteed 100% coverage with a minimum thickness of 0.5” over all internal tank surfaces. In comparison, glass lining is approximately 0.005” thick and includes imperfections, pinholes and variation in coverage thickness resulting in portions of unprotected steel tank exposed to corrosion. In an attempt to compensate, glass lined tanks include a sacrificial anode in an effort to slow down the corrosion of the tank. HydraStone lined tanks on the other hand do not require an anode due to the integrity of the lining. As such, a cement lined tank will far outlast a glass lined tank.
Although we don’t advocate dropping our tanks, sometimes stuff happens. The Vaughn HydraStone lining is a minimum of 1/2" thick (100 times thicker than a glass lined tank) and is guaranteed to uniformly cover 100% of all internal tank surfaces. In essence, the Vaughn HydraStone lining is a tank within a tank and should have no problem withstanding the rigors of shipping and installation. A properly maintained Vaughn tank will last decades.
Legionella is the bacteria responsible for Legionnaire’s Disease, an acute bacterial infection of the lower respiratory tract. This bacterium was first identified in 1977 by the Centers for Disease Control. Pontiac Fever is a less severe, non-pneumonia, flu-like disease that is associated with and likely caused by Legionella bacteria.   Legionella is a fairly common water bacterium and has been found to exist widely in many surface water sources including lakes, rivers, streams and ponds.  It can also be found in ground water sources and some soils.   At the levels found in these naturally occurring sources it typically does not pose a threat to public health.  When the bacterium enters a domestic water system it can find an ideal host environment of warm water temperatures (105-115°F), stagnant water areas (isolated storage tanks and dead-end piping legs) and ample food sources (sediment, scale, deposits and biofilm). Under these conditions Legionella can rapidly colonize, forming higher concentrations that can pose the public health threat of Legionnaire’s Disease.    There are many methods of controlling colonization of Legionella bacteria; a widely accepted and preferred method is to maintain the hot water system storage temperature continually at or above 140°F.  Unfortunately, the elevated temperature necessary to minimize the growth of and kill Legionella bacteria has the potential to cause serious thermal shock and scalding injuries.  As such, many plumbing engineers will specify that the water heater be set to maintain water temperatures at 140°F or higher to reduce the risk of Legionella, but then specify the appropriate mixing valve to ensure safe delivery of hot water to the fixtures.  For a more thorough discussion of Legionella please go to here and the following link to the US Department of Labor OSHA information regarding Legionnaires’ Disease OSHA here
The unique design of the Vaughn heat exchanger electrically isolates the heat exchanger from the tank by means of a non conductive barrier installed between the two. This provides dielectric isolation between the tank and the heat exchanger thereby eliminating electrolysis between the two due to dissimilar metals. This feature is one reason why the Vaughn indirect water heater far outlasts competitor models.

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