Instant Gas to Heat Pump Hot Water: Is It Worth Upgrading?
Instant Gas to Heat Pump Hot Water: Is It Worth Switching?
For many homes, yes. If you have room for a storage cylinder, switching from continuous-flow gas to heat pump can cut hot-water energy use, work extremely well with solar PV and reduce or remove gas dependence.
This is a bigger physical conversion than replacing one storage tank with another. Instant gas is a compact wall-mounted appliance that heats water only when you open a tap. A heat pump stores hot water in a cylinder, so the property needs a suitable tank position, drainage, airflow and electrical supply. Where those conditions are practical, heat pump is usually the upgrade we would compare first.
Should You Switch From Instant Gas?
This gives a preliminary direction only. Final suitability depends on tank space, household demand, electrical supply, drainage, airflow, noise, gas services and the selected heat-pump model.
1What else uses gas at the property?
2Do you have room for a storage cylinder?
3Do you have rooftop solar PV?
Guide only. A licensed installer must confirm plumbing, electrical, gas, drainage, airflow, clearances, noise and household-demand requirements for the selected system.
Can You Replace Instant Gas With a Heat Pump?
Yes. A natural-gas or LPG continuous-flow water heater can be replaced with a heat-pump hot-water system where the property has a suitable location for a storage cylinder and the required plumbing, electrical and drainage work can be completed. The conversion changes both the energy source and the way hot water is delivered: instant gas heats on demand, while a heat pump stores a reserve of hot water.
Why Move From Instant Gas to Heat Pump Hot Water?
The main reasons are lower hot-water energy use, better use of rooftop solar, potential certificate incentives and the option to reduce dependence on natural gas or LPG. Australian Government guidance identifies heat pumps as the cheapest hot-water system to run because they are much more energy efficient than gas or conventional electric systems.
Lower Running Energy
Heat pumps move heat rather than creating it directly from combustion or resistance heating, which is why they can achieve very low operating energy for stored hot water.
Use Your Solar PV
A heat pump can be scheduled during daylight hours so rooftop solar can contribute directly to water heating instead of exporting that electricity while gas heats the water separately.
Potential STC Discount
Eligible air-source heat-pump models can create Small-scale Technology Certificates when the exact model and completed installation meet current scheme requirements.
Reduce Gas Dependence
If hot water is the last major gas load, the conversion can create an opportunity to separately consider whether the property still needs an ongoing gas supply.
Better Fit for Electrification
Heat pump hot water works naturally with a home moving toward solar PV, battery storage, induction cooking and efficient electric heating and cooling.
Stored Reserve
A correctly sized tank keeps a ready reserve of hot water and can be heated when electricity is cheapest or solar generation is strongest.
Instant Gas vs Heat Pump: Current Installed Today Starting Prices
Compare the complete conversion, not just the appliance price. Instant gas can be cheaper and easier when replacing like-for-like. Heat pump usually has a higher purchase and conversion cost, but that needs to be weighed against lower operating energy, solar-PV use and eligible incentive pathways.
Usually the simplest replacement where the existing gas supply, wall position, flue clearances and water services remain suitable.
Current Installed Today collection starting price. Final price depends on gas type, flow rate, installation scope and selected options.
Adds a storage cylinder and electrical hot-water pathway, but can materially reduce hot-water energy use and integrate directly with solar PV.
Eligible heat pumps may qualify for STCs or other incentives depending on model, property, location and provider requirements.
Instant Gas vs Heat Pump Hot Water
| Consideration | Instant Gas | Heat Pump |
|---|---|---|
| How it heats | Gas burner heats water as it flows through the appliance | Refrigeration cycle transfers heat from surrounding air into stored water |
| Hot-water format | Continuous flow No hot-water storage tank | Stored reserve Tank capacity and recovery must suit the household |
| Ground space | Strong advantage Compact wall-mounted appliance | Needs a suitable storage-cylinder position |
| Solar PV compatibility | PV cannot directly supply the gas burned by the appliance | Strong advantage Can run from household electricity while solar is generating |
| Energy source | Natural gas or LPG, plus small electrical use on many electronic units | Electricity, with most heat transferred from surrounding air |
| STCs | No heat-pump or solar-water-heater STC pathway | Eligible listed models may qualify when installed to scheme requirements |
| Noise | Burner and fan noise during hot-water use | Compressor and fan operate during heating |
| Peak demand | Strong continuous delivery within the appliance's flow-rate capability | Depends on stored volume, recovery rate and operating schedule |
| Gas dependence | Gas remains essential to normal hot-water operation | No gas required for normal hot-water heating |
| Our preference if both suit | Best where compact continuous flow or limited space is decisive | Heat pump is generally the recommended long-term upgrade |
The Biggest Change: You Need Somewhere for the Heat-Pump Tank
Instant gas is often mounted to an external wall and can occupy very little usable ground area. A heat pump changes that. Before choosing the model, identify a practical cylinder location with enough room for the tank, compressor or integrated head, airflow, drainage and future servicing.
Ground-Level Space
The selected system needs a stable, suitable base and enough footprint for the tank and required clearances.
Water Pipe Route
The existing hot and cold services at the instant unit may be useful, but pipework generally needs to be rerouted to the new storage position.
Relief Drainage
Stored hot-water systems require relief discharge arrangements, and the heat pump may also produce condensate that needs a suitable discharge path.
Airflow
The heat-pump section needs access to a useful volume of air and must meet the manufacturer's installation clearances.
Noise Position
Consider bedroom windows, close boundaries, courtyards and reflective walls before locking in the new tank location.
Service Access
Leave practical room for future maintenance around valves, electrical components, fan, compressor and controls.
What Happens to the Existing Gas Connection?
The gas connection serving the old instant unit needs to be safely dealt with by the appropriate licensed trade. Whether the property keeps its broader natural-gas or LPG supply depends on what else still uses gas.
Keep the Property Gas Supply
Gas cooking, heating or other appliances can continue using the existing supply. The redundant hot-water branch still needs to be made safe and compliant as part of the conversion.
Consider Full Gas Exit Separately
If nothing else requires gas, changing hot water to heat pump can create an opportunity to review whether ongoing gas supply charges and the broader gas connection are still needed. Closing or abolishing the supply is a separate process from removing the water heater.
Will the Existing Instant-Gas Power Point Run a Heat Pump?
Do not assume it will. Many continuous-flow gas units use electricity only for ignition, controls and fans, so an existing nearby outlet or circuit may not be suitable for the new heat pump. The electrical arrangement needs to be checked against the exact model and local installation requirements.
Existing Power May Be Light Duty
The old gas appliance usually does not have the same electrical role as a heat-pump water heater, so the existing supply cannot simply be assumed adequate.
Model Requirements Differ
Plug-in and hard-wired heat pumps can have different supply, isolation and protection requirements. Check the exact appliance before finalising the installation scope.
Solar Scheduling Matters
If rooftop PV is available, the electrical setup and control strategy can be designed around daytime operation where that suits the chosen heat pump and household demand.
Already Have Solar PV? Heat Pump Is Usually the Standout Choice
Instant gas and rooftop solar largely operate in separate energy worlds. Your PV can power the gas unit's small electrical components, but it cannot replace the natural gas or LPG burned to heat the water. A heat pump can directly use household solar electricity.
Instant Gas
Provides excellent on-demand delivery, but normal water heating still depends on gas regardless of how much excess solar electricity the home is exporting.
Heat Pump + Solar
Schedule hot-water recovery into the solar window and use a relatively small electrical load to move heat into the stored water.
Heat Pump + Battery
Lower electrical demand can also reduce the amount of battery energy consumed by water heating compared with a large resistance-heating load.
If you already have good rooftop PV and enough room for a heat-pump cylinder, we would strongly favour heat pump over replacing instant gas like-for-like unless continuous-flow delivery or site constraints are unusually important.
Instant Gas Flow Rate vs Heat-Pump Tank Size
This is the sizing change customers notice most. Instant gas systems are commonly compared by litres per minute because they heat water continuously. Heat pumps are compared by stored tank capacity and recovery performance. A 26L/min gas unit does not translate into a 260L heat-pump tank or any other simple formula.
Household Size
Occupants matter, but so do shower lengths, bath use and how much hot water is used at the same time.
Peak Shower Demand
Instant gas can continue delivering while fuel and water flow are available. A heat pump needs enough stored volume and recovery to handle the home's peak period.
Daytime Recovery
Homes with solar can intentionally heat during the day, but the tank still needs enough capacity to carry demand through the rest of the day and night.
Climate
Ambient conditions can affect heat-pump performance, so model suitability and recovery should be considered for the installation climate.
Backup Heating
Some systems use an electric element for boost or recovery support. How that backup is controlled can affect both recovery and energy use.
Future Demand
Allow for growing families, renovations, extra bathrooms or changes in occupancy rather than choosing the smallest tank that works today.
When We Would Highly Recommend Heat Pump Over Instant Gas
If several of these conditions apply, heat pump is normally the pathway we would push to the top of the shortlist.
Hot Water Is Your Last Gas Appliance
Moving hot water to electricity can make a broader gas exit possible and remove the reason to keep gas purely for water heating.
You Already Have Solar PV
This is one of the strongest reasons to switch because a heat pump can directly use electricity your roof is already producing.
You Have a Good Tank Position
Once storage space, airflow and noise are solved, the biggest physical disadvantage of moving away from instant gas largely disappears.
You Use LPG
A heat pump removes the normal need to buy LPG for hot-water heating and can avoid bottle-management issues associated with that load.
You Plan to Electrify the Home
Heat pump hot water fits naturally with induction cooking, electric heating and cooling, solar PV and battery storage.
You Expect to Stay Long Term
A longer ownership period gives the lower operating-energy requirement more time to offset the higher conversion cost.
When Staying With Instant Gas Can Still Make Sense
Heat pump is our preferred long-term direction where the site suits, but instant gas has real strengths. The right reason to keep it is usually physical practicality or delivery preference rather than energy efficiency.
No Practical Tank Space
A wall-mounted gas unit can fit where a full storage cylinder simply cannot. In a genuinely space-constrained property, that advantage can decide the job.
Very High Continuous Demand
Some households strongly value long, back-to-back hot-water use without managing stored capacity. A correctly sized continuous-flow gas system remains excellent at that job.
Gas Is Staying Anyway
If major gas appliances will remain and the instant unit can be replaced very simply, the total conversion economics may be less compelling than in an all-electric transition.
Can an Instant-Gas-to-Heat-Pump Upgrade Qualify for STCs?
Eligible air-source heat-pump water heaters can create federal Small-scale Technology Certificates when the exact model is on the current register and the installation meets scheme requirements. The Clean Energy Regulator's register includes eligible air-source heat pumps and their certificate values by installation zone.
Eligible Models Can Qualify
The exact model, eligibility dates, system configuration and completed installation all matter. Similar-looking products should not be assumed to have identical certificate eligibility.
Extra Incentives May Apply
Some states and territories have additional heat-pump discounts, rebates or finance. These can depend on postcode, existing heater, household eligibility, approved product and provider.
Confirm the Claim Path First
Buying an eligible heat pump by itself does not complete a certificate or rebate claim. Confirm the installer or accredited provider process before installation where required.
Supply Only vs Supplied & Installed
Installed Today sells heat-pump hot-water systems online for supply-only ordering across suitable Australian metro delivery areas, with supplied-and-installed options available on selected products in eligible Brisbane and Gold Coast service areas.
Arrange Your Own Licensed Trades
Because this is a gas-to-electric technology conversion, confirm the complete plumbing, gas and electrical scope before ordering. The product alone does not include gas isolation, tank base, drainage, electrical work, pipe relocation or incentive paperwork unless specifically shown.
Available Where Offered
Where an installed option is available, use the product's installation choices to build the required scope. Availability still depends on the address, site, tank position, gas work, electrical requirements and selected heat pump.
How an Instant-Gas-to-Heat-Pump Conversion Usually Works
Choose the Tank Location
Confirm enough room, airflow, drainage, access and sensible noise separation for the heat pump.
Size the System
Convert from flow-rate thinking to stored capacity and recovery based on household demand.
Confirm Gas & Electrical Work
Plan safe treatment of the redundant gas branch and confirm the new heat pump's electrical requirements.
Install & Commission
Complete plumbing, gas, electrical, drainage and control setup, then finalise any eligible certificate pathway.
Instant Gas to Heat Pump Hot Water FAQs
Can I replace instant gas hot water with a heat pump?
Yes. The property needs a suitable position for the heat-pump storage cylinder plus the required plumbing, electrical, drainage, airflow and service clearances. The redundant gas connection also needs to be dealt with appropriately.
Is heat pump cheaper to run than instant gas?
Heat pumps are generally very cheap to run because they transfer heat rather than creating it directly. Australian Government guidance describes heat pumps as the cheapest hot-water system to run. The actual household saving depends on local gas and electricity prices, hot-water use, system efficiency, solar PV and operating schedule.
Is it worth switching from natural gas to heat pump hot water?
It can be particularly attractive when the home has rooftop solar, hot water is the last gas appliance, the existing gas system needs replacement or the property has a good outdoor location for a heat-pump cylinder. Upfront conversion work should still be compared with the expected long-term energy benefit.
Is it worth switching from LPG instant gas to heat pump?
Often it is worth a strong comparison because a heat pump removes LPG from normal water heating and can use household electricity or rooftop solar instead. Tank space, electrical work and household demand still need to be checked.
Do I need to remove the gas connection completely?
Not necessarily. If other appliances still use gas, the broader supply can remain while the old hot-water branch is made safe. If hot water was the last gas appliance, closing or abolishing the property gas supply can be considered separately.
Can the heat pump use the power point from my instant gas unit?
Do not assume so. Continuous-flow gas units often use electricity only for controls, ignition or fans. The heat pump's electrical supply, isolation and protection requirements need to be checked against the exact selected model.
How do I compare a 26L instant gas unit with a heat-pump tank?
There is no direct litres-per-minute to tank-litres conversion. Instant gas is sized around continuous flow capability, while heat pumps need enough stored volume and recovery for the household's peak hot-water demand and operating schedule.
Is heat pump better if I already have solar panels?
Usually this is one of the strongest reasons to switch. Rooftop PV cannot supply the gas burner, while a heat pump can run during the day using household-generated electricity and store that energy as hot water.
Can I get STCs when replacing instant gas with a heat pump?
Eligible air-source heat-pump models can create Small-scale Technology Certificates when the exact model is on the current Clean Energy Regulator register and the completed installation meets scheme requirements.
When is instant gas still the better fit?
Instant gas can remain the more practical fit where there is no sensible ground space for a storage cylinder, continuous-flow delivery is a high priority, gas will remain heavily used elsewhere, or the heat-pump conversion requires disproportionate site work.
Can I buy the heat pump supply only?
Supply-only ordering is available on suitable products and delivery areas. Because this conversion can involve plumbing, gas and electrical work, confirm the complete licensed-trade scope and any STC or state-incentive pathway before installation.
Replacing Instant Gas? Compare Heat Pump Before You Buy Another Gas Unit
If you have a practical tank location, heat pump is the upgrade we would compare first. It can move hot water away from gas, pair directly with rooftop solar and substantially reduce the energy required for everyday water heating while keeping a stored reserve ready for the household.
