Heat pump hot water systems are changing quickly.
They are no longer simply an energy-efficient alternative to a conventional electric storage system. Manufacturers are now improving refrigerants, efficiency, recovery performance, installation flexibility and even the way homeowners control when their water is heated.
Rheem’s current heat pump range provides a good example of that change.
The familiar Rheem Ambiheat HDc-270 remains part of the range, but it now sits alongside newer products such as the AmbiPower 280e and AmbiPower 5kW Split. Rheem has also added EcoNet Wi-Fi connectivity to the AmbiPower 280e.
So why keep developing new heat pumps when the existing technology already worked?
The answer tells us quite a lot about where residential hot water is heading.
Heat pumps are becoming a mainstream hot water option
For many years, replacing a hot water system often meant installing another version of whatever was already there.
An electric storage system failed, so another electric storage system went in. A gas system failed, so another gas system was installed.
Heat pumps have changed that decision.
A heat pump does not rely primarily on an electric element to create heat. Instead, it uses a refrigeration cycle to collect heat from the surrounding air and transfer that heat into the stored water.
That can make the process considerably more energy efficient than directly heating the same water with a conventional electric resistance element.
One way manufacturers measure this is through Coefficient of Performance, or COP.
A COP of 1 would mean roughly one unit of electrical energy produces one unit of useful heat. A heat pump can achieve a much higher ratio because much of the heat is being transferred from the surrounding air rather than created directly from electricity.
Rheem lists the AmbiPower 280e with an average COP of 5.2 under its specified test conditions.
That figure should not be interpreted as a guarantee that every household will experience exactly the same performance. Ambient temperature, incoming water temperature, installation conditions and the way the household uses hot water all affect real-world operation.
But it demonstrates why heat pump technology has attracted so much development.
The refrigerant has changed
One of the biggest differences between generations of heat pumps is something homeowners rarely see: the refrigerant circulating inside the system.
The Rheem Ambiheat HDc-270 uses R513a.
The newer AmbiPower 280e and AmbiPower 5kW Split systems use R290.
Why does that matter?
Refrigerants have what is known as a Global Warming Potential, or GWP. This provides a way of comparing the potential climate impact of different refrigerant gases.
Rheem classifies R290 as an ultra-low-GWP refrigerant, while R513a is classified as low GWP within its range.
This means the development of a heat pump is no longer only about reducing how much electricity the system consumes. Manufacturers are also changing the refrigeration technology inside the appliance.
That is an important part of understanding why newer heat pumps exist.
The AmbiPower 280e pushes efficiency further
The Ambiheat HDc-270 is still a capable heat pump and remains part of Rheem’s current Australian range.
Rheem lists it with a 270-litre storage capacity and an average COP of 4.5 under its test conditions.
The AmbiPower 280e increases storage slightly to 280 litres and Rheem lists an average COP of 5.2.
Rheem also states that the AmbiPower 280e can achieve up to 73.9% lower water-heating energy consumption than a comparable electric water heater under the modelling conditions used for Australian Climate Zone 3.
That does not mean every household will automatically reduce its bill by 73.9%. Electricity tariffs, hot water demand, climate, installation conditions and operating times all matter.
What the figures do show is the direction of product development: manufacturers are trying to extract more useful heat from each unit of electricity consumed.
But higher COP is not the entire story
This is where hot water selection becomes more interesting.
If you looked only at COP, you could assume the model with the highest number is automatically the best system.
That is not necessarily true.
The Ambiheat HDc-270, for example, has different recovery characteristics to the AmbiPower 280e. Household size, peak demand and how quickly the system needs to recover after several showers can be just as important as the headline efficiency figure.
A family using large amounts of hot water over a short period has different requirements from a two-person household with relatively predictable usage.
That is why we prefer to look at the complete application rather than choosing a hot water system from one specification.
The AmbiPower Split solves a completely different problem
Rheem’s AmbiPower 5kW Split shows another direction in heat pump development.
Instead of combining the heat pump and storage cylinder into one integrated appliance, the system separates them.
Rheem offers the Split system with either a 315-litre vitreous enamel tank or a 325-litre stainless steel tank.
The heat pump module can be positioned separately from the tank. Rheem specifies that the tank can be installed up to five metres away from the module and can potentially be located indoors, such as inside a garage, while the heat pump module can be mounted on the ground or wall.
Why would you want that?
Because real houses rarely have perfect hot water system locations.
There may be:
- limited side access;
- windows near the existing system;
- bedrooms close to the installation position;
- narrow passages;
- existing pipework that would be expensive to relocate; or
- very little suitable outdoor space.
A split system gives the installer more flexibility to work around the property.
That is a fundamentally different type of improvement from simply increasing efficiency.
It is solving an installation problem.
Hot water systems are becoming connected appliances
The latest change to the AmbiPower 280e is another sign of where hot water technology is heading.
Rheem now offers the system with EcoNet Wi-Fi control.
Through the connected system, homeowners can access information and alerts, manage energy use, control temperature, schedule holiday modes and activate additional hot water when required.
At first, putting a hot water system on an app might sound unnecessary.
But there is a bigger reason why this matters.
The timing of electricity use is becoming more important
A growing number of homes now have rooftop solar.
Electricity tariffs can also vary depending on when energy is consumed.
That means the question is gradually changing from:
“How much electricity does my hot water system use?”
to:
“How much electricity does it use, and when does it use it?”
A heat pump that can be scheduled gives the household greater control over that second question.
For a suitable home with rooftop solar, for example, it may be possible to schedule more of the water heating during periods when the solar system is generating electricity.
That turns the hot water system into part of the home’s broader energy system rather than an appliance operating completely independently from it.
So is the AmbiPower 280e better than the Ambiheat HDc-270?
Not automatically.
And this is probably the most important point.
A newer product does not suddenly make the previous model a bad hot water system.
Rheem continues to list the Ambiheat HDc-270 alongside the AmbiPower range.
Instead, there are now more options designed around different requirements.
When we look at a heat pump installation, some of the things worth considering include:
- household size;
- daily hot water consumption;
- peak hot water demand;
- recovery requirements;
- available installation space;
- water quality;
- electrical requirements;
- existing solar;
- when the household normally uses hot water;
- upfront installation cost; and
- expected long-term running costs.
The correct answer can therefore be different from one house to the next.
What Rheem’s changing range tells us about the future of hot water
When you look at the changes across Rheem’s range, there is a fairly clear pattern.
Heat pump systems are becoming:
- more energy efficient;
- more sophisticated in their refrigerant technology;
- more flexible to install;
- better suited to different household sizes and usage patterns; and
- more controllable as part of the home’s overall energy system.
That does not mean every home should automatically switch to a heat pump.
Electric storage, gas storage, continuous-flow gas, solar hot water and heat pumps all have applications where they can make sense.
What has changed is that replacing a hot water system like-for-like is no longer always the obvious decision.
There are now considerably more options available.
Choosing a heat pump hot water system in Moreton Bay
If you are replacing a hot water system in North Lakes, Mango Hill, Griffin, Kallangur, Murrumba Downs or the surrounding Moreton Bay area, RJT Plumbing & Gas can help you compare the available options.
That may include systems from the Rheem Ambiheat or AmbiPower range, but the recommendation should depend on the property, household and hot water demand rather than simply choosing the newest model.
The best hot water system is not necessarily the newest one or the one with the biggest efficiency number. It is the system that best matches the way your household actually uses hot water.
If you are unsure which type of system suits your home, speak with RJT Plumbing & Gas or use our hot water system recommendation tool to start comparing your options.
Frequently Asked Questions
What is the difference between the Rheem Ambiheat HDc-270 and AmbiPower 280e?
The Ambiheat HDc-270 has a 270-litre tank and uses R513a refrigerant, while the AmbiPower 280e has a 280-litre tank and uses ultra-low-GWP R290 refrigerant. Rheem lists an average COP of 4.5 for the Ambiheat and 5.2 for the AmbiPower 280e under its specified testing conditions. The best choice still depends on hot water demand, recovery requirements and the installation.
What does COP mean on a heat pump hot water system?
COP stands for Coefficient of Performance. It compares the useful heat delivered to the water with the electrical energy consumed by the heat pump. A higher COP generally indicates greater efficiency under the stated testing conditions, although actual performance varies with temperature and installation conditions.
Why does the AmbiPower 280e use R290 refrigerant?
R290 has an ultra-low Global Warming Potential compared with many refrigerants traditionally used in heat pump and refrigeration equipment. Its use is part of the broader move towards refrigerants with lower potential environmental impact.
What is the advantage of a split heat pump hot water system?
A split system allows the heat pump module and hot water storage tank to be installed separately. This can provide greater flexibility where side access or outdoor space is limited or where the tank would be better positioned inside a garage or another suitable location.
Can a heat pump work with rooftop solar?
Yes. A heat pump uses electricity, so households with rooftop solar may be able to operate the heat pump during solar-generating periods. The actual benefit depends on the solar system, electricity tariff, household energy consumption and how the hot water system is configured.
Is a heat pump always the best replacement for an electric hot water system?
No. Heat pumps can offer significant efficiency advantages, but installation space, household demand, recovery requirements, electrical supply, upfront cost and other factors should all be considered before selecting a replacement system.
Frequently Asked Questions
What is the difference between the Rheem Ambiheat HDc-270 and AmbiPower 280e?
The Ambiheat HDc-270 has a 270-litre tank and uses R513a refrigerant, while the AmbiPower 280e has a 280-litre tank and uses ultra-low-GWP R290 refrigerant. Rheem lists an average COP of 4.5 for the Ambiheat and 5.2 for the AmbiPower 280e under its specified testing conditions. The best choice still depends on hot water demand, recovery requirements and the installation.
What does COP mean on a heat pump hot water system?
COP stands for Coefficient of Performance. It compares the useful heat delivered to the water with the electrical energy consumed by the heat pump. A higher COP generally indicates greater efficiency under the stated testing conditions, although actual performance varies with temperature and installation conditions.
Why does the AmbiPower 280e use R290 refrigerant?
R290 has an ultra-low Global Warming Potential compared with many refrigerants traditionally used in heat pump and refrigeration equipment. Its use is part of the broader move towards refrigerants with lower potential environmental impact.
What is the advantage of a split heat pump hot water system?
A split system allows the heat pump module and hot water storage tank to be installed separately. This can provide greater flexibility where side access or outdoor space is limited or where the tank would be better positioned inside a garage or another suitable location.
Can a heat pump work with rooftop solar?
Yes. A heat pump uses electricity, so households with rooftop solar may be able to operate the heat pump during solar-generating periods. The actual benefit depends on the solar system, electricity tariff, household energy consumption and how the hot water system is configured.
Is a heat pump always the best replacement for an electric hot water system?
No. Heat pumps can offer significant efficiency advantages, but installation space, household demand, recovery requirements, electrical supply, upfront cost and other factors should all be considered before selecting a replacement system.
