Which is the best hot water heat pump?
You've got space for a storage tank and you're ready to upgrade your hot water system to the incredible efficiency of heat pump technology...but which product should you choose?
Not sure if a heat pump is the way to go? Head to our article, 'How can I replace my gas hot water heater?'
In this article, we will save you time by providing an overview of the technology and some considerations, before recommending the best option based on your requirements and preferences.
No space for a storage tank indoors or outdoors? Sign up to an Energy Freedom Homes Masterclass we can connect you with experts who will recommend a unit based on your budget, needs/wants, space and installation time requirements. Check your Masterclass readiness now!
A quick summary of heat pump technology
Heat pumps work on the same principle as a fridge or air conditioner.
They extract heat from the air.
They then use the heat from the air to heat a very cold refrigerant. In the case of a hot water system, the energy from the warmed refrigerant is then transferred into water1.
Because the refrigerant is so cold, heat pumps can extract heat from the air even at sub-zero temperatures.
The brilliance of this process is that heat pumps can extract about 3 units of heat energy from the air for every unit of energy put in from electricity! This makes the running costs for a heat pump very low compared to other technologies.
Key considerations
Integrated or split system
Heat pumps have two different systems available: integrated or split system. These two options enable heat pumps to be appropriate for many different circumstances.
An integrated system is when all the components of the hot water system are in one unit. The heat pump is usually mounted on top of the storage tank.
A split system is when the heat pump and the storage tank are separate. The heat pump and storage tank are connected by refrigerant piping (just like a split system air conditioner). These are great if you have less outdoor space but have somewhere indoors to locate the storage tank.
Not all brands have both options, so it is worth checking what is available before making a decision on brand.
Refrigerant
When thinking about heat pump product options, an important thing to consider is the refrigerants used in the heat pump.
Some, such as R290, are one hundred per cent natural refrigerants, containing near-zero ozone-depleting substances.
Others, like R410A, can have very detrimental impacts on the environment if the refrigerant leaks or is released.
One way to show the impact of refrigerants is to measure the heat they absorb in the atmosphere compared to carbon dioxide (CO2). This is known as Global Warming Potential (GWP2).
Here's a comparison of the GWP of different gases, including refrigerants:
Gas | Global Warming Potential (GWP) |
Methane | 27 - 30 |
CHC-11 | 47503 |
R410A | 19204 |
R290 | 34 |
Methane is considered one of the worst gases for global warming5, yet it causes a fraction of the damage that R410A can.
You may remember that CFCs were banned in Australia in 1995 because they contributed to the hole in the ozone layer. R410A will do similar damage if released.
Luckily, just like with CFCs, it's easy to choose a product that doesn't have a negative environmental impact.
Warranties
Most entry-level products will only cover you for 12 months and after that you're on your own. Pick the right mid-range product and you can get as much as 5 years. Top of the range heat pumps often give you 10+ years of cover on some system components.
This can massively reduce the financial risk you are taking on by investing in a new system. Treat warranty periods as one of your most important decision-making factors.
Check what components or labour the guarantee covers. Sometimes the tank will have a longer warranty period than the electronics, or other critical components.
Installers
Installers will be the ones to honour guarantees if something goes wrong.
Make sure your installer is established with a strong track record. We put all our tradies through checks to make sure they are reliable.
If you would like to learn more about our process and the checklist we use, you can have a read in our article, 'How to find a trusted tradie'.
Also, make sure you get licensed tradespeople to complete the work so the install is to accreditation standards and they are able to issue a compliance certificate.
Depending on your requirements, the replacement may involve electrical and plumbing work and so looking for a provider that can do both will save you time and potentially money.
Water temperature
One other thing to expect when you update your hot water system is that the temperature of the water coming out of the taps may be lower.
This is not about the heat pump, rather it's because there's a relatively recent legal requirement to install a tempering valve, which you may not have installed on your current system.
This valve cools down the water coming from the tank to a level where it can't scald people.
Remember how you're always mixing the water from the hot tap with cold water so you can actually get your hands wet without burning yourself? Exactly.
Anti-bacterial measures
Hot water storage systems for residential buildings must be heated to a minimum temperature of 60°C to prevent the growth of bacteria that can cause harm to humans, such as Legionella.
Most heat pumps have a in-built setting to periodically boost the water temperature above 60°C, so this shouldn't be an issue. However, it doesn't hurt to check that this function is included in the heat pump you are considering.
Options based on your requirements
Your budget is tight
Source: https://ecoalliance.com.au/products/
If money is really tight, the Eco-Alliance Dynaheat is a good option. Eco-Alliance are an established company and the Dynaheat has good ratings on ProductReview6.
If you're replacing an existing resistive electric hot water system, there's a good chance you can get the unit installed for free. However, if you're replacing a gas hot water heater, the cost of adding a new power supply for the unit and retiring the existing gas system will cost around $500.
Depending on the size of your household, the Dynaheat comes with different storage tanks sizes of 115L, 215L and 310L. There should be no change in cost for the different sizes.
The Dynaheat configuration has the heat pump as a separate unit to the storage tank (some are integrated into a single unit), so you'll need to make sure you've got space outside for the two units.
Eco-Alliance are one of a number of companies offering "free" hot water heat pumps that are subsidised by government rebates. Most of the products in this category and the companies offering them are alike, so it's not worth spending too much time trying to distinguish between budget options.
What's the downside of choosing the "free" option? Like other "free" options, the Dynaheat only comes with a 12 month warranty. You run the risk of wasting your once-off government rebates on a product that will need to be trashed after a year.
The efficiency and operating noise of the Dynaheat (and budget units in general) is worse than the mid- and high-range alternatives. This means you (and your neighbours) may well notice this heat pump when it is running.
The Dynaheat uses R410a as a refrigerant. As we discussed above, this gas has a high global warming potential and, when released, will contribute to climate change. If you care about the environmental impact of your purchase, it's worth paying a bit extra to move beyond the budget options.
Even though a freebie is an enticing option, we'd strongly encourage you spend a bit more and get a hot water system with a longer guarantee, better efficiency, reduced operating noise and lower environmental impact.
The additional cost will spread out over the lifetime of the product and you'll probably even cover the additional cost via the savings from a more efficient unit.
Another limitation of these units is the power of the pump, which means if you need to separate the compressor and storage tank to put the storage tank inside, the pump will struggle.
You're after a balance of price and quality
If you're looking for the sweet spot of bang for buck, Aquatech are a fantastic option. Their Rapid/X6 unit is popular with homeowners and has good ratings on ProductReview7.
Including rebates, it'll cost you more than a budget unit; around $1000 if you're replacing an electric resistive storage system and around $1500 if you're getting rid of a gas-based system.
However, the additional cost is well worth it.
The unit is designed specifically for the Australian climate and can operate effectively to sub-zero temperatures.
It operates at a lower noise level than the budget alternatives and comes with a 5 year warranty.
The Rapid/X6 is an integrated unit, with the heat pump sitting on top of a 213L storage tank that can handle a household of up to 6 people. This means you'll need a smaller footprint outdoors to get the unit installed.
The unit also uses r290, a one hundred per cent natural refrigerant containing near-zero ozone-depleting substance and near-zero global warming potential.
You want a high-end product
If money is less of an issue, you'll get major benefits from the additional spend. The Reclaim Energy CO2 Heat Pump has rave reviews on ProductReview8 and is regarded by many to be the best-in-class product for hot water heat pumps.
As for the Eco-Alliance product, the Reclaim unit has separate heat pump and tank components, so you'll need to make sure you've got space for them both outside.
If you've got no space outdoors for a storage tank, this unit supports an installation of the tank indoors. The pump in the compressor is strong enough to be installed outdoors and move the heated water to the storage tank for a distance up to 15 metres.
Storage tanks come in a range of sizes to match the requirements of different households, including 160L, 250L, 315L and 400L.
The unit literally operates whisper-quiet and has impressive efficiency and environmental credentials due to the use of CO2 as a refrigerant.
It also comes with a warranty that covers labour for 2 years, heat pump compressor parts for 6 years and the tank for up to 15 years.
However, these impressive specifications come at a cost; even factoring for rebates, you'll still be looking at a price tag of $3500+ to get a unit installed.
Installation tips
Hopefully, by now you're clear on the best heat pump hot water product for you. As you start thinking about your install and speaking to tradies, here are a couple of tips to make sure you get the most out of your heat pump.
Insulating pipes
It's important to make sure your installer properly insulates the pipework on the water heater. About 30% of the energy used to heat water in a storage system is wasted in heat loss from the tank and associated pipework, so reducing this as much as possible is important.
Tank location
Another way to minimise heat loss is to keep hot water pipes as short as possible. When selecting a location for the storage tank choose somewhere close to all points of hot water use. If you're able to afford the Reclaim unit, this location could be somewhere indoors as well as outdoors. An example is below.
Source1
Next steps
Hopefully you've picked out the best hot water heat pump for your circumstances.
If you are all set with your planning for hot water upgrades, take a moment to congratulate yourself! When you are ready to move to the next area of upgrades in your journey to an Energy Freedom Home, such as cooking or space heating, click here to head to our planning article.
Ready to get your heat pump installed? Make sure you have the right installer to get the job done. We have some advice in our 'How to find a trusted tradie' article...
...or join an Energy Freedom Homes Masterclass and learn to identify your needs, gain expert installation advice, and meet trustworthy tradespeople. Check your Masterclass readiness now!
The recommendations in this article come from talking with real people and communities to identify a best-fit option for a range of priorities. We also do our research; each of the above recommendations is based on ratings from Product Review and general consensus from the popular Facebook group, My Efficient Electric Home.
References
1 Riedy, C., Milne, G., Ryan, P., Alviano, P., & Dwyer, S. (2020). Hot water systems. Australian Government: Department of Climate Change, Energy, the and WaterEnvironment. Retrieved 2023, from https://www.yourhome.gov.au/energy/hot-water-systems
2 EPA: United States Environmental Protection Agency. (2022). Understanding Global Warming Potentials. Retrieved 2023, from https://www.epa.gov/ghgemissions/understanding-global-warming-potentials
3 EPA: United States Environmental Protection Agency. (2022). Ozone-depleting substances. Retrieved 2023, from https://www.epa.gov/ozone-layer-protection/ozone-depleting-substances#:~:text=The%20GWP%20is%20the%20ratio,ranging%20from%2093%20to%2012%2C100.
4 Shaik, S. V., Shaik, S., Gorantla, K., Mahapatra, D., & Setty, A. B. P. (2020). Investigation on thermodynamic performance analysis and environmental effects of various new refrigerants used in air conditioners. Environmental Science & Pollution Research, 27(33), 41415–41436. https://doi.org/10.1007/s11356-020-09478-6
5 Garthwaite, J. (2021). Methane and climate change. Stanford Earth Matters magazine. Retrieved 2021, from https://earth.stanford.edu/news/methane-and-climate-change
6 Product Review. (n.d.). EcoAlliance Dynaheat. Retrieved 2023, from https://www.productreview.com.au/listings/ecoalliance-dynaheat
7 Product Review. (n.d.). Aquatech Rapid/X6. Retrieved 2023, from https://www.productreview.com.au/listings/aquatech-rapidx6
8 Product Review. (n.d.). Reclaim Energy CO2 Heat Pump Hot Water System. Retrieved 2023, from https://www.productreview.com.au/listings/reclaim-energy?page=2