John Nighingale — Professional Plumber at Plumb It Right
How Much Does a Heat Pump Hot Water System Cost to Run in Perth?
Key Takeaways
- •A heat pump pulls heat from the surrounding air, so it uses far less electricity than an element-based storage unit to heat the same water.
- •Your actual bill depends on your electricity tariff, household size and when the unit runs, so work it out from the unit's rated daily kWh.
- •Pairing a heat pump with rooftop solar lets you run it on your own power during the day.
- •The trade-off is a higher upfront price than a basic electric storage unit.
- •Plumb It Right quotes fixed prices with no callout fee, so the installation cost is known before work starts.
You want to replace your hot water system and every brochure quotes a different running cost, none of them based on your house. The honest answer is a method, not a single number, and it takes about five minutes to work through.
What Is a Heat Pump Hot Water System, and What Does It Get Confused With?
Same tank idea as electric storage, very different way of making heat.
A heat pump draws heat from the surrounding air and uses electricity mainly to run a compressor and fan. A standard electric storage unit uses a heating element to create all of that heat itself. That difference is why heat pumps are cheaper to run.
People often mix it up with solar hot water, which uses roof collectors, and with an air conditioner, which moves heat for room comfort. A heat pump hot water unit is a dedicated appliance that heats a storage tank. Our heat pump hot water page covers the units we supply and install.
For the full side-by-side of every system type, read the hub article, Perth Hot Water Systems Explained: Heat Pump, Solar, Gas or Electric?
How Do You Calculate Your Own Heat Pump Running Cost?
Three inputs and one multiplication give you a real figure.
Take the daily energy use in kWh from the unit’s specification sheet for your household size. Multiply by your electricity rate per kWh from your latest bill. Multiply by 365 for an annual figure.
Then run the same sum for your current system. Ask your installer for the rated figures on both units so you compare like for like, and use your actual tariff, not an average.
If you have rooftop solar or a battery, the heat pump can run on your own generation in the middle of the day. One recent customer review of our iStore 270L heat pump install said the tank integrates well with their solar and battery setup.
Which Hot Water Systems Cost the Least to Run in Perth?
Ranked on running cost first, with the trade-offs stated plainly.
I have ranked these five on the criteria in the next section. Plumb It Right sells and installs heat pumps, so note the drawback I list under the first entry. I have not quoted dollar figures because tariffs and household use vary too much.
1. Heat pump, best for lowest electricity use per litre of hot water
A heat pump uses electricity to move heat from the air, not to generate it from an element. That is why it sits first for running cost on electricity. It also pairs well with rooftop solar because the unit can heat during sunny hours.
The drawback is price. A heat pump costs more to buy and install than a basic electric storage unit, so the saving has to pay that gap back over the system’s life. It also needs an outdoor spot with airflow.
Best suited for: Households on electricity that want the lowest ongoing power use, especially with solar panels. It is a poorer fit if you are moving within a few years and will not recoup the higher upfront cost.
2. Solar hot water, best for households with strong roof sun exposure
Solar hot water collects heat from the sun, so much of the energy is free. It still needs a booster (gas or electric) for low-sun days, and that booster is where your ongoing bill comes from. See our solar hot water page and the related article Solar Hot Water in Perth: Is It Worth It and What Rebates Are Available?
Best suited for: Homes with an unshaded, suitable roof and steady daytime hot water use. It suits you less if your roof is shaded or space is limited.
3. Gas instantaneous, best for homes already on mains gas with variable demand
Instantaneous units heat water only when a tap opens, so there is no tank sitting hot and losing heat. Your cost follows your gas tariff and how much you use. Our gas hot water page explains the range, and the article Gas Storage vs Gas Instantaneous Hot Water compares the two types.
Best suited for: Homes with mains gas and irregular hot water use, such as a couple or a holiday house. Gas work must be done by a licensed gas fitter in WA.
4. Gas storage, best for large households with steady demand
A gas storage unit keeps a full tank hot, so it spends gas maintaining temperature even when nobody is home. It delivers plenty of hot water at once, which is why larger families choose it.
Best suited for: Larger households on mains gas that want ample hot water at once. It is less efficient for people who are out most of the day.
5. Electric storage, best for lowest upfront cost and simple replacement
An element heats the whole tank, so electric storage typically has the highest running cost of the five. It remains the cheapest to buy and the simplest swap-over. Read Electric Storage Hot Water Systems: Pros, Cons and When They Still Make Sense for the full case, and see our electric storage page.
Best suited for: Tight budgets, rentals or short-term ownership where upfront price matters more than the bill. If you stay long term, expect to pay more in electricity.
How Did We Rank These Hot Water Systems?
Rankings are earned on the criteria below, not by what we sell. Where a rival wins a criterion, the table shows it.
Energy source
The fuel each system uses (air heat plus electricity, sun plus booster, gas, or electricity alone), because that sets your tariff exposure.
Standing heat loss
Whether a hot tank is kept warm all day, which adds running cost when nobody is home.
Relative running cost
Each system's typical position from lowest to highest for ongoing energy spend in a household of the same size.
Relative upfront cost
Where each system sits from cheapest to most expensive to buy and install, since this decides the payback period.
Site requirement
What your property needs, such as mains gas, roof space or an outdoor spot with airflow.
Side-by-Side Comparison
| Option | Best for | Relative running cost | Relative upfront cost | Site requirement |
|---|---|---|---|---|
| 1. Heat pump | Households on electricity that want the lowest ongoing power use, especially with solar panels. | Lowest of the electric options | Higher | Outdoor space with airflow |
| 2. Solar hot water | Homes with an unshaded, suitable roof and steady daytime hot water use. | Low, plus booster use | Highest of the five | Suitable sunny roof |
| 3. Gas instantaneous | Homes with mains gas and irregular hot water use. | Moderate, follows gas tariff | Moderate | Mains gas, licensed gas fitter |
| 4. Gas storage | Larger households on mains gas that want ample hot water at once. | Moderate to higher, tank loses heat | Moderate | Mains gas, licensed gas fitter |
| 5. Electric storage | Tight budgets, rentals or short-term ownership where upfront price matters most. | Highest | Lowest | Standard electrical supply |
Which Hot Water System Fits Your Situation?
Match your own situation to the closest row. If two fit, run the kWh sum on both. If your current unit is failing, Signs Your Hot Water System Needs Replacing and What to Do Next helps you judge the timing.
| If you are… | Look for | Best fit |
|---|---|---|
| You have rooftop solar or a battery and use most hot water in the evening | A unit that can heat during the day and store the hot water | 1. Heat pump |
| You have a large sunny roof and plan to stay long term | Free solar heat with a booster for low-sun days | 2. Solar hot water |
| You are on mains gas and use hot water at irregular times | Heating only on demand with no hot tank waiting | 3. Gas instantaneous |
| You have a big household and want plenty of hot water at once on mains gas | A large tank and high delivery volume | 4. Gas storage |
| You are renting out or selling soon and want the lowest upfront cost | Cheapest purchase and a like-for-like swap | 5. Electric storage |
Heat Pump Running Cost Questions Answered
Straight answers to what Perth homeowners ask before they buy.
Is a heat pump cheaper to run than electric storage?
Yes. A heat pump moves heat from the air instead of generating all of it with an element, so it uses less electricity for the same hot water. Compare the rated daily kWh on both spec sheets to see the gap for your household.
Will a heat pump work with my solar panels?
It can. Running the unit during daylight lets it use your own generation, and one of our customers reported their heat pump tank integrates well with their solar and battery. Ask your installer about the unit’s timer or control options.
Does a heat pump still work on cooler Perth winter days?
Heat pumps can work in cool conditions, though output and efficiency vary by model. Check the manufacturer’s stated operating range and ask what happens if the unit cannot keep up.
How do I get a price for installing one?
Call or text John on 0408 012 993 for an upfront quote. Plumb It Right uses fixed pricing with no callout fee, so you know the cost before work begins.
Ready to Find Out What a Heat Pump Would Cost You?
Call or text John Nightingale on 0408 012 993 for a free quote. Fixed pricing, no callout fee, and you know the cost before we start.
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Part of our guide: Perth Hot Water Systems Explained: Heat Pump, Solar, Gas or Electric?
John Nighingale
Professional Plumber · Plumb It Right
John Nightingale has 38+ years’ experience of working in the plumbing industry in Perth Western Australia and previously in the United Kingdom.
