Heat-pump hot water in Tasmania: replace now or wait?
If your hot-water cylinder is still working, you have time. In Tasmania that is worth using. You can look at the options before the cylinder fails and you have to take whatever is available that day.
On a normal weekday, write down when hot water is used. Morning showers, evening showers and visitors can all matter. On the same notes, write down when the cylinder reheats now: overnight, during the day, or whenever the stored water cools. Keeping the cylinder, changing the timer, or replacing it all have to cover that pattern.
Age is a reason to start planning. It does not tell you the cylinder is finished. If you are unsure of its condition, ask a tradesperson. Keep the model details and any service records with your notes.
| Option | What to check |
|---|---|
| Keep the existing cylinder | Condition, likely maintenance, and when it reheats now |
| Keep it and change the timing | Whether the controls and the supply arrangement can match your notes |
| Replace it with a heat pump | What is included, whether the size suits your notes, how it behaves in cold weather, and which refrigerant it uses |
Use the same household pattern, and the same electricity price assumptions, for each option. Include installation, electrical work, plumbing and removal. If an incentive is confirmed, write it separately from one that only might apply.
What to ask if you are quoted a heat pump
A heat pump uses electricity to move heat from the outside air into the water. These systems work best in warmer, more humid climates. In a colder climate the efficiency drops, because the refrigerant picks up less heat from the air. Many models are still designed for cold climates, including freezing weather and cold, dry air. Ask for performance information for your site.1
Many heat pumps also have a boost element. It heats the water directly when the weather is very cold, or when you are using a lot of hot water. If that element runs often, the unit can cost more to run.1
Ask which refrigerant is in the unit. The common ones are carbon dioxide (R744), propane (R290), R134A and R513A. A carbon dioxide unit is what installers usually call a CO2 heat pump. Propane and carbon dioxide are natural refrigerants. Your Home describes their global warming potential as negligible. R134A and R513A are HFCs, and theirs is not. If a high-GWP refrigerant leaks, through a fault, poor installation, a failure or illegal disposal, that can undo the emissions benefit of using a heat pump.1
Also ask where it would go, and what it would sound like from nearby rooms and the boundary. On an integrated cylinder the fan sits on top of the tank, so noise can carry over a fence. A split system keeps the outdoor unit lower, and that unit can be placed in a warmer spot.1
If you have solar
Add one line to the notes: when there is spare solar left after the other loads in the house have run.
A timer can run the heat pump in that part of the day. Warmer air can help too, because the unit is taking heat from the air. If there is not enough solar in the timer window, the system uses grid electricity instead.1
Some heat pumps cannot be connected to a controlled-load circuit. A smaller cylinder on controlled load can also run out of hot water before the circuit comes back on. Storage above 250 litres is better suited to controlled load. Check the manual for the model you are considering, and have the installer confirm how it will be wired.1
Do not shorten the timer so far that the tank misses 60°C at least once every seven days. Stored hot water in a home has to reach that temperature to limit Legionella, and a timer that is too short can get in the way of it. New systems also have to keep water at the tap to no more than 50°C.1
After you have the notes
The useful outcome is a reason: keep the cylinder and keep an eye on it, change when it heats, or replace it. If you decide to wait, write down what would make you look again. A repair, a change in who is living there, or a renovation are the usual prompts.
You do not need a promised saving to get to that point. You need a suitable option, and a fair comparison with the cylinder you already have.
Frequently asked questions
What should I check before replacing hot water in Tasmania?
On a normal weekday, write down when the household uses hot water and when the cylinder reheats. Use those notes to compare keeping it, changing the timer, or replacing it with a heat pump.
What is a CO2 heat-pump water heater?
A CO2 heat pump uses carbon dioxide (R744) as the refrigerant. Propane (R290) is the other common natural refrigerant. R134A and R513A are the common HFC types. Your Home describes the global warming potential of propane and carbon dioxide as negligible. The HFC refrigerants are not. A leak of a high-GWP refrigerant can undo the emissions benefit of a heat pump. Ask which refrigerant is in the quote, how the unit performs in cold weather, and when the boost element runs.
If you want this worked through with the rest of the home, book a home energy assessment.
