Residential Heat Pump
40-119 Gallon
Efficient
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 Vaughn Heat Pump Water Heater offers a low-maintenance, affordable way to bring green technologies to your home.
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.

Features
- 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
- Long Life
- HydraStone lining ensures long tank life
- Proven heat pump technology
- Incoloy sheathed back-up electric elements resist corrosion and mineral build up
- No anode rod required
- 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 Information
- 10 year limited tank warranty
- Heavy Duty Construction
- Thick gauge carbon steel storage vessel with 1/2" seamless HydraStone cement lining
Additional Product Details
Heat Pump Functions
- 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.
- The evaporator coil captures heat energy in the air and transfers that energy to a specially formulated CFC free refrigerant contained within the evaporator.
- The refrigerant changes from a liquid to a gas as it gets warmer.
- The refrigerant, now as a warm gas, exits the evaporator and passes into a compressor.
- The warm gas is compressed, causing it to become a superheated hot gas and then flows to the heat exchanger.
- The heat exchanger transfers heat energy from the superheated hot gas to the cold water from the tank.
- 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.
- Hot water exits the heat exchanger and is stored in the tank.
- The superheated gas condenses back to a liquid and awaits to repeat the process.


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 efficency 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.
Sizing & Dimensions

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 | 67 | 43 | 9 | 325 |
65 | S65WHPT3838I | 28 | 64.25 | 40 | 9 | 365 |
80 | S80WHPT3838I | 28 | 74.25 | 50 | 9 | 440 |
119 | S120WHPT3838I | 30 | 85 | 61 | 9 | 525 |
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 is 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) | ||||||||||
Ambient Air Temp |
Coefficient of Performance (COP) (Ratings Not Certified by AHRI) |
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 | $354 | 2950 | $354 | 4671 | $561 | 4289 | $515 | |
70°F | 2.6 | 1759 | $211 | 1759 | $211 | 4671 | $561 | 3733 | $448 | |
90°F | 3.4 | 1350 | $162 | 1350 | $162 | 4671 | $561 | 3404 | $408 |
Options
- 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