Gas Storage to Solar Hot Water
Gas Storage to Solar Hot Water: Is It Worth Switching?
From gas-fired stored hot water to solar-heated storage — what changes on the roof, what happens to gas and whether solar or heat pump makes more sense.
Replacing gas storage with solar hot water keeps the basic idea of a stored reserve but changes how that water is heated. Instead of relying primarily on a natural-gas or LPG burner, solar collectors contribute heat from the sun and a booster supports the system when required. Your existing tank position can be useful for a split-solar conversion, but it can also make a heat-pump upgrade particularly straightforward, so compare both pathways before deciding.
Does Solar Suit Your Gas Replacement?
You already have a storage position. The big questions are what happens to gas and whether your roof gives solar a genuine advantage.
1 What does gas currently serve?
2 What is the roof like?
3 What matters most?
Guide only. Roof exposure, tank position, collector layout, gas services, booster requirements, electrical supply and household demand all need to be checked before finalising the conversion.
Can You Replace Gas Storage With Solar Hot Water?
Yes. Natural-gas or LPG storage hot water can be replaced with solar hot water where the property has suitable roof area and installation conditions. Because both technologies use stored hot water, the existing tank position and plumbing can often provide a useful starting point for a split-solar installation. The major additions are roof collectors, solar pipework and a suitable booster system.
Existing Tank Position
A suitable gas-storage position can potentially be reused for a split-solar cylinder or a heat pump.
Roof Collectors
Solar adds dedicated roof-mounted thermal collectors that did not form part of the old gas-storage system.
Gas Connection
The gas branch serving the old storage unit needs to be safely isolated or altered as part of the conversion.
Booster
Backup heating supports the solar system when available solar contribution does not meet household demand.
One Big Advantage: You Already Have a Storage Hot Water Site
Unlike an instant-gas conversion, gas storage already gives the property a full-sized hot-water tank position. That can make the physical conversion to either split solar or heat pump considerably more logical.
Tank Space Already Exists
The home is already accustomed to allocating ground-level space to a storage cylinder.
Water Services Already Exist
Hot and cold services around the existing gas tank can often provide a practical starting point for another storage system.
Drainage May Already Be Nearby
Existing relief-valve drainage and surrounding plumbing can be useful, subject to the requirements of the selected replacement.
Split Solar or Close-Coupled Solar After Gas Storage?
Ground-Level Tank + Roof Collectors
Split solar is the most direct physical comparison with gas storage because the new storage cylinder remains at ground level.
Where the old gas tank position has suitable space, plumbing, drainage and service access, it can potentially provide a practical location for the solar tank.
Solar pipework then connects the ground-level storage cylinder to the collector array on the roof.
Tank + Collectors on the Roof
Close-coupled solar moves both the storage tank and solar collectors onto the roof.
This can free the ground-level area previously occupied by the gas-storage cylinder.
Roof structure, tank weight, pitch, material and installation access become much more important with this configuration.
Why Change From Gas Storage to Solar Hot Water?
The main reason is to shift a major household energy load from ongoing gas combustion toward renewable solar energy.
Reduce Gas Consumption
Solar contribution can significantly reduce the amount of purchased fuel required to keep household hot water available.
Use Direct Solar Thermal Energy
Solar collectors capture energy from sunlight specifically for heating the stored water.
Move Away From Gas
Where hot water is the last gas appliance, the conversion can create an opportunity to separately consider whether the broader gas supply is still required.
Gas Storage, Solar & Heat Pump: Current JR Starting Prices
Compare complete installed pathways rather than appliance prices alone. Solar introduces roof-based work that gas storage and heat pump may not require.
Usually the most straightforward pathway where the existing gas supply, tank location and services remain suitable.
Current JR advertised starting price. Final price depends on fuel type, tank size, recovery and installation scope.
Adds dedicated solar collectors and can substantially reduce purchased water-heating energy where the property suits solar thermal.
Eligible systems may qualify for JR's current upfront STC pathway.
Keeps the familiar ground-level storage format while removing gas from normal water heating and avoiding dedicated solar-thermal collectors.
Eligible heat pumps may also qualify for JR's current upfront STC pathway.
Gas Storage vs Solar Hot Water vs Heat Pump
| Consideration | Gas Storage | Solar Hot Water | Heat Pump |
|---|---|---|---|
| Main heat source | Natural gas or LPG | Solar thermal + booster | Heat from surrounding air + electricity |
| Hot-water delivery | Stored water + gas recovery | Stored water + solar contribution + booster | Stored water + heat-pump recovery |
| Ground-level tank | Yes | Yes with split solar | Normally yes |
| Roof equipment | None for hot-water heating | Dedicated solar collectors | No dedicated solar-thermal collectors |
| Solar PV compatibility | PV does not power the gas burner | Uses separate solar-thermal collectors | Can directly use household PV electricity |
| Gas use | Required for normal heating | Can be eliminated from hot-water heating with a suitable non-gas booster configuration | No gas required for normal operation |
| Operating noise | Burner operation | No heat-pump compressor; split systems may use circulation equipment | Compressor and fan operate while heating |
| STC pathway | No solar / heat-pump STC pathway | Eligible listed systems may qualify | Eligible listed systems may qualify |
| Strongest reason to choose | Simple replacement and strong gas recovery | Direct solar thermal heating | Efficient gas-free storage with easy PV integration |
Can Solar Use the Same Position as the Gas Storage Tank?
Often the existing position can provide a useful starting point for split solar, but it still needs to suit the dimensions and installation requirements of the selected solar storage cylinder.
Existing Base
The existing tank foundation may be useful if its size, condition and position suit the replacement system.
Hot & Cold Plumbing
Existing water services can often be incorporated, although connection positions and pipework may need alteration.
Drainage
Relief and discharge arrangements still need to satisfy the requirements of the new system.
Solar Pipe Route
Split solar needs a practical route between the storage cylinder and the collector array on the roof.
Electrical Requirements
An electrically boosted solar system may require suitable electrical supply and protection at the tank position.
Heat Pump Comparison
The same location may also suit a heat pump where airflow, noise, electrical supply, drainage and servicing clearances are appropriate.
What Happens to the Existing Gas Connection?
The gas branch serving the old storage system needs to be safely isolated or altered. Whether the property continues to require a broader natural-gas or LPG supply depends on what else still uses gas.
The Property Gas Supply Can Remain
Cooktops, fireplaces and other gas appliances can continue using the existing supply.
Only the redundant gas connection serving the old hot-water system needs to be dealt with as part of the conversion.
Full Gas Disconnection Can Be Considered Separately
Replacing the gas-storage unit may create an opportunity to consider whether the property still needs an ongoing gas service.
Removing the hot-water system does not automatically close the gas account or disconnect the property from the network.
Is Your Roof Actually Suitable for Solar Hot Water?
This is the major new site requirement. Your gas-storage system did not depend on solar exposure, but solar thermal does.
Usable Roof Area
Enough practical roof space is needed for the collector configuration required by the household.
Solar Exposure
Collector position and available sunlight affect how much useful solar heat the system can contribute.
Shading
Trees, buildings and roof structures can reduce the performance potential of the collector area.
Roof Access
Height, pitch, material and safe access can materially affect installation complexity and future servicing.
Roof Loading
A close-coupled system puts the tank and stored water on the roof as well as the collectors.
Existing Solar PV
PV may already occupy the strongest roof area and can also strengthen the argument for using a heat pump instead of adding a separate thermal collector array.
What Happens When the Sun Is Not Providing Enough Heat?
Solar hot water stores energy collected during suitable solar conditions, but the system still needs backup heating for periods of low solar contribution, high demand or poor weather.
Electric Boosting
An electric booster can support the solar system without retaining gas as the normal backup energy source.
Gas Boosting
Some solar configurations can use gas backup, although retaining gas may work against the goal where the customer is deliberately trying to electrify the home.
Sizing Matters
Tank capacity, collector area and household usage all affect how frequently backup heating is required.
Already Have Solar PV? Heat Pump Becomes a Very Strong Comparison
Solar thermal and solar PV are different technologies. Solar hot water needs dedicated thermal collectors; a heat pump can use electricity from the PV system already installed on the home.
Gas Storage
Rooftop PV cannot provide the natural gas or LPG burned by the storage system.
Solar Thermal
Dedicated roof collectors directly heat the hot-water system and use their own roof area.
Heat Pump + PV
A heat pump can operate during daylight hours and use household-generated electricity while keeping the existing ground-level storage concept.
If the home already has substantial rooftop PV and a suitable gas-storage tank location, moving to heat pump can be an especially clean pathway: the tank stays at ground level, gas is removed from normal hot-water heating and no additional solar-thermal collector array is required.
Solar or Heat Pump: Which Makes More Sense After Gas Storage?
Both retain stored hot water and can substantially reduce reliance on gas. The strongest choice usually comes down to the roof, existing PV, installation complexity and whether direct solar thermal is specifically wanted.
The Roof Is Excellent and You Specifically Want Solar Thermal
Strong unshaded collector exposure and straightforward roof access give solar thermal its best opportunity to perform.
It also appeals where quiet operation without a heat-pump compressor is particularly important.
The Existing Tank Site Already Works
Gas storage has already established a ground-level cylinder position. If that location also has suitable airflow, drainage, electrical access and clearances, heat pump can be a relatively natural technology change.
Existing rooftop PV, limited roof space or difficult roof access makes this pathway even stronger.
Can Gas-Storage-to-Solar Hot Water Qualify for STCs?
Eligible listed solar water heaters can create Small-scale Technology Certificates when the exact system and completed installation meet current scheme requirements. Eligible listed air-source heat pumps can also qualify.
Eligible Solar Systems Can Qualify
Eligibility depends on the exact listed system, approved configuration, installation date, location and completed installation.
Eligible Heat Pumps Can Qualify Too
Heat pump should not be excluded from the comparison simply because solar uses dedicated collectors. Both eligible technologies participate in the current STC scheme.
When Gas Storage to Solar Can Genuinely Make Sense
Excellent Sunny Roof
Strong collector exposure allows the home to make meaningful use of direct solar thermal energy.
Direct Solar Heating Is Preferred
Some homeowners specifically want dedicated thermal collectors rather than a refrigeration-cycle system.
Quiet Operation Matters
Solar avoids the compressor and large outdoor fan used by heat-pump systems.
Gas Is Being Phased Out
Moving hot water away from gas can form part of a wider household electrification strategy.
Ground Space Could Be Reclaimed
A suitable close-coupled solar system can move the storage tank onto the roof and free the old gas-storage position.
Long-Term Energy Reduction Matters
A well-matched solar system can substantially reduce purchased energy compared with continually heating stored water using gas.
When Heat Pump Is Usually the Stronger Move Away From Gas Storage
Gas-storage homes are often good heat-pump conversion candidates because the property already accommodates a full-sized outdoor storage cylinder.
Existing Tank Site Is Suitable
Space, plumbing, drainage and an established hot-water position can reduce the amount of redesign required.
Rooftop Solar PV Already Exists
Heat pump can use electricity from the solar system already installed rather than needing another dedicated collector array.
Roof Is Shaded
Heat-pump efficiency does not depend on dedicated sunny roof exposure in the way solar thermal does.
Roof Space Is Limited
Keeping the hot-water system at ground level preserves roof area for existing or future PV.
Lower Conversion Complexity Matters
Heat pump avoids the dedicated collector mounting and solar pipework required by a full solar-thermal conversion.
Simple Gas Removal Is the Goal
Heat pump provides a straightforward efficient electric pathway where the customer mainly wants to stop using gas for water heating.
When Staying With Gas Storage Can Still Make Sense
Lowest Conversion Complexity Matters
A straightforward gas-storage replacement can avoid changes to the energy source, roof and broader installation layout.
Strong Recovery Is a Priority
Gas storage can provide strong burner recovery for households with concentrated periods of heavy hot-water demand.
The Property Is Already Gas-Dependent
If several other major appliances will remain on gas, changing hot water alone may provide less benefit than it would in a home moving toward full electrification.
How a Gas-Storage-to-Solar Conversion Works
Compare Solar & Heat Pump
Decide whether direct solar thermal or an efficient ground-level heat pump better suits the property before changing technology.
Assess the Roof
Check collector area, sunlight, shading, roof material, access and structural requirements.
Choose Split or Close Coupled
Decide whether to keep a storage cylinder at ground level or move the tank onto the roof.
Size the Solar System
Match tank capacity and collector configuration to occupants, bathrooms, household use and expected solar contribution.
Remove Gas Storage
Isolate and remove the old cylinder and safely deal with its gas connection and existing services.
Install & Commission Solar
Install the tank, collectors, valves, solar pipework, booster and controls, then commission the completed system.
Gas Storage to Solar Hot Water FAQs
Can I replace gas storage hot water with solar?
Yes. Natural-gas or LPG storage can be replaced with solar hot water where the roof, tank position and installation conditions suit the selected system.
Is switching from gas storage to solar worth it?
It can make sense where the home has strong solar exposure and the customer wants to reduce purchased gas by using direct solar thermal energy. Heat pump should also be compared because the existing gas-storage tank position can often suit another ground-level storage system.
Can split solar use the same location as my gas tank?
Often the existing position can provide a useful starting point. The base, tank dimensions, hot and cold water services, drainage, electrical requirements and solar pipe route still need to suit the selected system.
Can I put the new solar tank on the roof?
A suitable close-coupled system can place both the storage cylinder and collectors on the roof. Roof structure, access, pitch, material and the selected system need to be assessed first.
What happens to the gas pipe?
The gas connection serving the old storage unit needs to be safely isolated or altered. The rest of the property gas supply can remain if other gas appliances still use it.
Can I disconnect gas completely after changing to solar?
Potentially, if hot water is the last gas appliance. Removing the water heater does not automatically close the gas account or disconnect the property supply, so broader disconnection needs to be considered separately.
Does solar hot water still need a booster?
Solar systems normally include backup heating for periods when solar contribution alone does not meet household demand. The exact booster arrangement depends on the selected solar system.
What happens on rainy or cloudy days?
Solar contribution can decrease during poor weather and periods of lower solar availability. The backup heating system supports the stored hot water when additional heating is required.
Is solar hot water cheaper to run than gas storage?
A well-performing solar system can obtain a significant share of its heating energy from sunlight instead of purchased gas. Actual household running costs depend on solar contribution, booster use, gas and electricity tariffs, system sizing and hot-water demand.
What if I already have rooftop solar PV?
Existing solar PV makes heat pump particularly worth comparing. A heat pump can use electricity already generated by the home's PV system, whereas solar hot water needs its own dedicated thermal collector array.
Is heat pump or solar better after gas storage?
Solar can be especially attractive where the roof has excellent exposure and the homeowner specifically wants direct solar thermal heating or very quiet operation. Heat pump can be stronger where the existing tank location is suitable, rooftop PV already exists, roof space is limited or efficient electrification is the main goal.
Is heat pump easier to install than solar after gas storage?
It can be. Both technologies may be able to use the existing ground-level storage position, but solar additionally requires suitable roof collectors and solar pipework. The actual installation difficulty depends on the property and selected system.
Does solar hot water qualify for STCs when replacing gas?
Eligible listed solar water heaters can qualify for Small-scale Technology Certificates when the exact system and completed installation meet current scheme requirements.
Do heat pumps qualify for STCs when replacing gas storage?
Eligible listed air-source heat pumps can also qualify for Small-scale Technology Certificates when the exact model and completed installation meet current requirements.
Does JR's $1,000 upfront STC discount apply to solar?
JR's current policy applies its $1,000 including GST upfront STC discount to eligible solar-hot-water and heat-pump systems supplied and installed by JR, subject to final STC eligibility and assignment requirements.
Moving Away From Gas Storage? Compare Both Renewable Pathways
Solar hot water can be an excellent choice where the roof has strong exposure and you specifically want direct solar thermal heating. Because your home already has a full-sized storage-tank position, compare a heat pump too — especially if rooftop PV already exists, roof space is limited or the main goal is simply to reduce gas use and long-term running costs.