17 Facts On Heat Pump Water Heater:Efficiency,Benefit,Setup

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By Debarghya Roy

Heat pump water heaters are an efficient way to heat and store hot water for domestic use. Additionally, they have the added benefits of reduced noise levels and minimal environmental impact thanks to less burning fossil fuels while operating. 

In this blog post, we will know the meaning, efficiency, benefits, cons and several other aspects related to heat pump water heaters.

What Is A Heat Pump Water Heater?

Heat pump water heaters are a type of energy-efficient appliance used to heat and store hot water for home use. They work by transferring heat from one place to another using electricity, allowing the user to save money and reduce their environmental footprint.

Heat Pump Water Heater

Heat Pump Water Heater

How Does a Heat Pump Water Heater Work?

Heat Pump Water Heaters (HPWHs) are efficient and energy-saving appliances that use electricity to move heat from one place to another instead of generating new heat. 

Heat pumps move hot air from cooler areas such as outside or inside your home into warmer areas like the storage tank which holds the heated water. 

Step-by-step working process of heat pump water heater:

  • Unlike traditional electric water heaters, HPWHs employ a process known as refrigerant cycle.
  • A fan at the top of the unit draws in air across the HPWH which then passes over a compressor. 
  • The compressor acts like a pump to increase the pressure of the refrigerant, creating high temperatures that move through copper tubes within an internal aluminum heat exchanger inside the storage tank.
  • Because copper is an excellent conductor of heat, it efficiently transfers this thermal energy into liquid stored in the tank where it is made available for your hot water tap or shower head.
  • This process uses energy only to transfer existing heat rather than generate new electrical resistance heating like traditional electric water heater designs.

Energy Efficiency Of Heat Pump Water Heater

Heat pump water heaters take advantage of the efficient process of transferring energy from one form to another, as opposed to generating heat.

This helps them reach up to seven times more efficiency than standard electric resistance or natural gas models by essentially “re-using” already existing warm air instead of burning fossil fuels to generate new heat.

The technology behind a typical heat pump cycles refrigerants through an enclosed system inside the unit, absorbing and releasing energy in order to move cold refrigerant around a closed loop.

Types Of Heat Pump Water Heaters

Hybrid Electric Water Heaters

Hybrid electric water heaters, also known as heat pump water heaters, are highly energy-efficient alternatives to traditional electric resistance water heaters. 

Working Of Hybrid Electric Water Heaters

It generates its own internal heat like a traditional electric model does, the hybrid uses electricity to move thermal energy from one place to another and then transfers it into the tank of hot water.

The components of a hybrid electric system include an electrically powered fan which pulls air across a plate at the top of the unit that contains coils filled with refrigerant.

This evaporates inside and takes in excess heat from surrounding areas before transferring it into warm cold lines that travel back down into your storage tank.

Benefits Of Hybrid Electric Water Heaters

  • This technology makes them much more efficient than standard models using roughly two thirds less energy in similar situations.
  • It saves money on your utility bill. 
  • It helps reduce stress on the environment by reducing emissions from burning fossil fuels for regular heating.

Performance Platinum Water Heaters

The Rheem Performance Platinum Heat Pump Water Heater is one of the leading heat pump water heaters for residential and commercial use. 

This heater is powered by a reversing valve that allows it to switch between using electricity or natural gas to generate hot water, making it more efficient than traditional electric water heaters.

It has an impressive energy efficiency that makes it ideal for anyone looking to reduce their energy costs and their environmental impact.

This top-of-the-line model also features the HydroBoost technology, which delivers faster hot water delivery while still maintaining its reliable performance. 

Its ENERGY STAR rating means that you can rely on this unit to remain highly efficient even in cold climates with regular maintenance after proper installation making it a great long term value for homes, offices and businesses alike.

Tankless Water Heaters

Tankless water heaters are an energy-efficient way of providing hot water on demand without the need for a bulky hot water tank. Rather than continually heating and storing water, it only heats water when it is requested.

Working Of Tankless Water Heaters

Unlike traditional tank models that store heated hot water in a large storage reservoir, tankless technology works by passing cold incoming supply through a series of heat exchangers that only generate heat on demand when activated by the flow sensor built into the unit.

These systems use either gas fired burners or electric coils to rapidly heat incoming cold supply as it passes through which results in instant and continuous hot water delivery without interruption perfect for spaces where larger tanks may be cumbersome such as small apartments or townhouses where space is often more precious than money.

Benefits Of Tankless Water Heaters

  • These systems also provide significant energy savings due to their high efficiency.
  • They can save up to 50% compared with an equivalent sized standard model.
  • Offer homeowners greater control over the temperature of their stored hot water
  • Adjustable thermostats help prevent scalding injuries when bathing and washing clothes or dishes.

Integrated Heat Pump Water Heaters

Integrated heat pump water heaters are a highly energy-efficient and cost-effective alternative to conventional electric resistance, gas and other traditional water heating systems.

Unlike conventional models which generate heat directly, these pumps use electricity to transfer temperature from the air or ground into the household hot water supply. 

The main difference between integrated heat pump systems and other types of heat pump models is their built-in storage tank. 

Integrated designs allow their owners to draw hot water whenever they need it instead of having to wait for it like with tankless models or constantly reheat standing liquid like with hybrid alternatives.

Additionally, this type usually comes equipped with multiple safety features such as 

  • Child locks on the temperature controls
  • Electronic shutoff valves
  • Dual thermostats that monitor both inlet and outlet temperatures at all times.

Standalone Heat Pump Water Heaters

Standalone heat pump water heaters are an innovative type of energy efficient technology that circulates air through a refrigerant, extracts the latent and sensible heat from the air to produce hot water for residential use.

Standalone units allow users to separate their source of hot water production from existing heating systems.

Working Of Standalone Heat Pump Water Heaters

This process works in conjunction with an absorption-type cooling cycle process complete with advanced micro-computer controls making them optimal at generating large quantities of hot water while consuming minimal amounts of power  between two and four times more efficiently than traditional electric resistance tanks.

Benefits Of Standalone Heat Pump Water Heaters

These standalone systems offer numerous benefits compared to traditional models like hybrid electric or tankless systems due to superior energy efficiency levels. 

By utilizing concentrated coils as its main mechanism, these standalone models can achieve up to 300% performance rating (with less electricity).

Components Of Heat Pump Water Heaters

Heat pump water heaters contain several essential components, such as a heat exchanger, compressor, refrigerant and an expansion valve.

Heat Exchanger

Heat exchangers are essential components of heat pump water heaters, serving as conduits for transferring thermal energy between the two incoming and outgoing sources of hot and cold water.

Heat exchangers consist of a network of pipes through which refrigerant circulates to pick up excess thermal energy in cooler temperatures or return it back in warmer conditions.

Different types like microchannel heat exchanger, plastic-aluminum hybrid radiators, ‘shell-and-tube’ design with bent tubes or fully welded plate type provide varying levels of efficiency due to their design differences.

The use of heat exchange technology allows for greater energy savings by taking advantage of ambient outdoor air in colder climates during winter when less heating is needed.


The compressor is an essential component of all heat pump water heater systems. 

It works by drawing in warm air, compressing it to increase its pressure and temperature, and then releasing it through the heat exchanger where it transfers energy to the refrigerant-water mix.

The rotary compressor has improved heating capacity, COP on rated conditions and efficiency for many generations of heat pump water heater systems compared with traditional ones incorporating scroll compressors or reciprocating compressors designed with double compression modules operating at equal frequency speed.

Heat pumps utilizing rotary compressors are also capable of providing warmer air in the heating mode than other existing heat pumps since they combine two stages into one motor rotating in opposite directions to achieve a much higher overall rotation speeds for optimal cold weather performance.


Heat pump water heaters use a type of fluid called refrigerant for operation. This fluid is pumped through a compressor and then dispersed to the cooler air at the back of the system.

CO₂-based R744 refrigerant has been promoted for being green in terms of performance, appliances efficient enough to use significantly lower amounts than standard systems with less environmental impact due to its more sustainable formula compared to traditional versions.

Expansion Valve

The expansion valve is one of the most vital components of a heat pump water heater, as it has several important roles in ensuring optimal performance. 

On the most basic level, an expansion valve regulates refrigerant flow from liquid to vapor form as it moves through different parts of a heat pump water heating system.

For instance, hybrid electric models contain both air source heat pumps and traditional electric storage units for added energy efficiency; their operation requires thermostatic expansion valves (TEVs) for effective control over refrigerant flow between components such as the indoor coil and central control panel.

Cost Analysis Of Heat Pump Water Heaters 

Initial cost, operating cost and lifespan of heat pump water heaters can be compared in detail by consulting the table.

Initial CostHeat pump water heaters generally have higher initial costs between $3000 – $10000 compared to conventional storage water heaters. This is primarily due to the advanced technology used in their construction, as well as specific components such as the compressor, condenser and evaporator coils that need installing.Despite its high initial cost however, modern heat pump technology ensures that these systems offer excellent value over long-term use with reduced usage costs.
Operating CostWhen compared to traditional electric water heaters, heat pump water heater systems are more energy-efficient and the associated operating cost savings can be significant.The major factors that affect the operating cost of a HPWH system include its, Efficiency ratingUsage patternsLocal climate conditionsType of installation optedIf several members in a household use multiple showers or hot baths simultaneously over long periods then this may increase operating costs.
Maintenance CostGetting a professional installer is key for long-term water heater lifespans that requires regular maintenance.As for maintenance, regularly scheduled inspections are necessary in order to prevent any problems or malfunctions from arising that costs around $550 for each session.Additionally, ensuring there is no build-up of dust and dirt can be done via frequent filter replacements as this will support efficient air flow into your system as well contribute to energy savings of up to 50%.

Benefits Of A Heat Pump Water Heater

Heat pump water heaters provide numerous benefits for homeowners, including:

  • Greater energy efficiency compared to conventional water heaters of up to 70%.
  • Lower electricity bills as the heat pump uses less energy than a traditional electric water heater.
  • Reduced operating costs due to lower amps consumption and low temperature set points.
  • Environmental friendliness because it does not burn fossil fuels like traditional electric or natural gas water heaters.
  • Environmentally friendly refrigerant offering a cooler air temperature in summertime while eliminating the use of chemical coolants.
  • Easy installation with minimal need for plumbing and electrical upgrades than what is required for a tankless water heater.
  • Low maintenance requirements over its long lifespan of up to 18 years.
  • No venting needed which allows the unit to be placed almost anywhere in the home, even closets and laundry rooms.

Environmental Benefits Of Heat Pump Water Heater

Heat pump water heaters are a much more efficient alternative to traditional gas or electric water heaters. 

  • They use up to two-thirds less energy than regular resistance heaters and significantly reduce emissions.
  • This is especially beneficial in communities where burning fossil fuels has the most significant impact on air quality. 
  • Heat pumps extract existing ambient warmth from the air, transferring it into their storage tanks to generate hot water unlike typical water heaters that require electricity or natural gas combustion to produce it.
  • As such, they can provide energy savings of up to $425 per year for a household of four people compared with a standard electric heater while helping reduce dependence on nonrenewable sources of energy such as coal and oil.
  • In addition, when used correctly they can almost eliminate waste through prolonged lossless standby operation.

Cons Of Heat Pump Water Heaters

  • Heat pump water heaters are more expensive than traditional electric or gas water heaters, with a higher initial cost.
  • In cold climates, they may become less efficient. This is due to the low temperature of the outside air and the consequent inability of their condenser coils to efficiently absorb heat from the outside environment.
  • Heat pump water heaters take longer than tanks or tankless hot water heating systems to provide heated water, so this can be an inconvenience in some situations where hot water needs to be provided quickly.
  • Heat pumps require more space for installation as compared with traditional electric and gas systems and need sufficient air flow around them in order for them to operate properly.
  • They also require regular preventive maintenance from a certified technician in order for them to work at peak efficiency and could potentially require additional electrical upgrades which could increase overall cost of ownership substantially over time.

How To Choose The Right Heat Pump Water Heater?

When selecting a heat pump water heater, factors such as size and capacity, operating conditions, climate considerations and maintenance requirements must be taken into account.

Size And Capacity Of Heat Pump Water Heater

Sizing and selecting the right heat pump water heater for a specific application is essential in achieving efficiency and reducing operating costs. 

Engineers and professionals must consider various factors such as hot water usage patterns, size of the household that will be using the unit, climate considerations, and consistent maintenance when making their selection.

Selecting an incorrect size or capacity can lead to significant energy losses resulting in higher running costs over time. 

For example, if the amount of hot water used exceeds what is produced by a unit in any given hour it could affect its ability to keep up with demand leading to temperature fluctuations that make bathing uncomfortable or inefficient washing results.

On the other hand, selecting too large of a heat pump water heater wastes energy because it takes longer for larger units to reheat stored hot water due to increased storage volume losses over time.

Operating Conditions Of Heat Pump Water Heater

Choosing the right heat pump water heater for your home should take into consideration the unit’s efficiency, performance and overall lifespan to have a good operating condition.

Factors such as climate, size and capacity of the tank, operating temperature, installation location and other conditions will all affect the performance of the heater over time.

Additionally, the installation environment can have an enormous effect on potential performance; most importantly it’s essential that air flow remains unrestricted around the outdoor unit so make sure there are no obstructions when selecting its placement.

Climate Considerations For Heat Pump Water Heater

Climate is a key factor when choosing a heat pump water heater. Various climate conditions, such as temperature range and humidity levels, can have an impact on the efficiency of the heat pump water heater.

In cold climates, for example, freezing temperatures may cause the system to run inefficiently.

In hot and humid climates meanwhile, there could be more strain on some parts of the system due to higher ambient temperatures and increased moisture levels.

There are 4 categories used by manufacturers which helps you determine the type of heat pump water heater that would suit best:

  • Very Cold (below 18°C)
  • Cold (18-23°C)
  • Mild (23-29°C) 
  • Hot/Humid (>29°C) 

Installation Of Heat Pump Water Heater 

It requires professional knowledge and skill, so it is best to hire a licensed technician when installing a heat pump water heater.

Location Considerations To Install Heat Pump Water Heater

When looking to install a heat pump water heater, it is important to take into consideration the location of the unit. 

Heat pumps need to be installed in areas that remain in the 40º–90ºF (4.4º–32.2ºC) range throughout the year, and they require at least 1,000 cubic feet of space available for air circulation around them.

The location is also very important with respect to a HPWH as its temperature range needs to lie between 16 – 35 degrees Celsius for optimal functioning thus placement should be carefully considered depending on climate conditions in order for it to perform well during winter seasons.

Selecting an appropriate location is vital when it comes to optimally reaping all energy savings promised by using this type of energy-efficient device while being mindful about reducing its costs over time.

Water And Electrical Connections 

One of the main steps in the installation process for a heat pump water heater is connecting necessary water pipes and wiring. 

  • Before starting any work, shut off both the water supply to the home and all power sources near the intended installation site.
  • To avoid potential damage or injury, know which valves control which lines and consider installing corrosion resistant housing for longer service life if needed. 
  • Connecting these components must follow all local building codes, including manufacturer guidelines related to pressure and temperature ratings.
  • The condensate pan also needs to be connected with a hose to drain away any moisture through a nearby floor drain as part of regular maintenance procedures.

Professional Installation Of Heat Pump Water Heater

Professional installation of a heat pump water heater is critical to ensure the optimal performance and energy efficiency of such systems. 

Incorrectly installed units may consume more electricity, generate improper temperature control, or even produce unsafe levels of carbon monoxide emissions.

Maintenance Of Heat Pump Water Heater

Regular and professional maintenance are important to keep a heat pump water heater in top condition.

Regular inspections should be done to ensure the parts are working correctly, filter replacement is necessary for optimal performance, and cleanings should routinely take place.

Regular Inspections

Regular inspections are an essential part of keeping a heat pump water heater in good working order. By catching problems early, costly repairs may be avoided and energy efficiency optimized.

Heat pumps should be inspected every 6 to 12 months by a professional service technician to check for: 

  • Wear and tear on the compressor
  • Presence of excessive dust buildup due to lack of adequate air flow 
  • Maintenance of airflow through ducts, proper functioning of the expansion valve and blower fan motor
  • Refrigerant pressures at various speeds
  • Deteriorated insulation within the cabinet or wall measuring area that can affect operation quality
  • Rust corrosion must also be checked

Cleaning And Filter Replacement

Regular cleaning and filter replacement is a vital part of heat pump maintenance. 

Cleaning the air filters of hybrid water heaters will ensure that the unit can operate at its maximum efficiency.

For instance, clogged air filters not only affect the performance, but also reduce the lifespan of these units by disallowing proper air circulation within the system. To clean them properly, wipe them with a damp cloth, rinse them underwater and allow to dry in an open-air setting before reusing it again.

Flushing out dirt and sediments from your heat pump regularly will stop particles from building up inside your appliance which could potentially cause damage over time due to wear and tear.

Additionally replacing dirty or worn-out filters on a regular basis helps to improve your unit’s energy efficiency while preventing wear-and-tear on parts like fan motor housings or burners caused by particle buildup in the long run.

Professional Maintenance

Having a heat pump water heater professionally maintained is essential in order to ensure that it operates optimally and provides energy savings. Professional maintenance includes several tasks such as,

  • During the professional inspection, the technician will check the electrical connections of the system
  • Replace filters if necessary.
  • Clean accumulations on parts such as compressors or motors; flush out sediments from storage tanks.
  • Clean air intakes of fans with an air filter device or brush attachment.
  • Inspect for excessive heating around exterior evaporator coils outside.
  • Test float switches that control high/low levels in a storage tank.

Comparison Of Heat Pump Water Heater Brands 

We will provide a comparison between two of the leading heat pump water heater brands, Rheem and AO Smith, to help you make an informed decision when choosing the right heat pump water heater for your needs.

BrandKey FeaturesAdvantagesDisadvantages
RheemHybrid Electric Water HeatersENERGY STAR certifiedLeak detection and shut-off systemWiFi connectivityHigh energy efficiency (up to 3.75 UEF)Reduced operating costsFlexible installation optionsSmart monitoring and controlHigher upfront costProfessional installation recommended
AO SmithHybrid Electric Water HeatersENERGY STAR certifiedDry fire protectionIntegrated electronic controlsHigh energy efficiency (up to 3.45 UEF)Reduced operating costsEasy operation and maintenanceHigher upfront costLimited smart monitoring featuresProfessional installation recommended

Water Heater Vs Heat Pump Water Heater

Comparing the differences between traditional water heaters and heat pump water heaters, it’s clear that investing in a modern and efficient solution can provide long-term savings.

CriteriaWater HeaterHeat Pump Water Heater
Differences In OperationConventional electric water heaters and standard gas-fired models generate heat directly with heating elements or burn natural gas respectively to heat the stored water. 

Heat Pump Water Heater does not require a tank and instead operates differently by extracting heat from one source such as outside air or underground resources to deliver warmth into another space such as in this case, hot water storage tanks located inside the home.
Energy EfficiencyHeat pump water heaters are incredibly energy-efficient. 
These hybrid electric systems use advanced technology to extract hot air from surrounding areas, like the ground or outside air and convert it into usable hot water.
This process uses approximately 60% less energy than traditional storage tanks.
Heat pumps work by compressing a colder refrigerant with an electric motor until it is heated and then transferring this heat to the water inside their tank which can hold up to 80 gallons of resulting hot water.
This method eliminates the need for constantly heating water so there’s no overspend on electricity and gas bills – even in cold climates.
Cost ComparisonA heat pump water heater has higher upfront costs than a conventional storage water heater, but there are several advantages in the long run. 
The average cost of a 50-gallon resistance water heater is $400.
while a typical heat pump 50-gallon water heater will cost around $1100.
Heat pumps can save an average household of four up to $330 per year on their electric bills due to its high efficiency rate.


The heat pump water heater is an energy-efficient and cost-effective solution for hot water needs in many homes, businesses, and other commercial spaces. Heat pumps are able to save up to two thirds more energy than a traditional electric water heater and can provide years of worry-free operation with proper maintenance.

Heat Pump