Gas Storage to Solar Hot Water: Is It Worth Upgrading?
Gas Storage to Solar Hot Water: Is It Worth Switching?
It can be an excellent move where the roof genuinely suits solar thermal - but if the solar case is only marginal, a heat pump is usually the stronger long-term alternative.
Gas storage already gives the home a full-sized hot-water tank position. That can make a split-solar conversion relatively logical because the new solar cylinder may be able to use a similar ground-level site while collectors are added to the roof. The real decision comes down to roof exposure, gas removal, booster type, installation complexity, existing solar PV and whether a heat pump can achieve the same goal with less roof infrastructure.
Does Solar Suit Your Gas Storage Replacement?
This is a preliminary guide. Final suitability depends on roof exposure, collector layout, gas services, tank position, booster requirements, electrical supply, drainage and household demand.
1What is the roof like?
2What else still uses gas?
3What matters most?
Guide only. Solar exposure, roof condition, tank location, collector pipe routes, gas isolation, booster type, electrical work, drainage and household demand must be checked before finalising a conversion.
Can You Replace Gas Storage With Solar Hot Water?
Yes. Natural-gas or LPG storage can be replaced with split or close-coupled solar hot water where the property has suitable roof exposure and installation conditions. Because gas storage already uses a full-sized cylinder, the existing tank area can often provide a useful starting point for a split-solar system.
Gas Storage vs Solar vs Heat Pump: What Actually Changes?
All three provide stored hot water, but the energy source, roof requirements and ongoing fuel use are very different.
| Consideration | Gas Storage | Solar Hot Water | Heat Pump |
|---|---|---|---|
| Main heat source | Natural gas or LPG burner | Direct solar thermal + booster | Heat from surrounding air + electricity |
| Stored hot water | Yes | Yes | Yes |
| Roof equipment | None for water heating | Required Dedicated collectors or evacuated tubes | No dedicated thermal collectors |
| Solar PV compatibility | PV does not power the gas burner | Uses a separate thermal collector system | Strong advantage Can use household PV electricity |
| Operating noise | Burner operation | Usually very quiet; some split systems use circulation equipment | Compressor and fan operate while heating |
| Gas use | Required for normal heating | Can be removed from hot-water heating with suitable non-gas boosting | No gas required for normal operation |
| STCs | No renewable-hot-water STC pathway | Eligible listed systems may qualify | Eligible listed systems may qualify |
| Best fit | Simple like-for-like replacement where gas remains preferred | Excellent sunny roof and direct solar thermal preference | Efficient gas-free upgrade where PV exists or roof conditions are marginal |
Why Move From Gas Storage to Solar Hot Water?
Gas storage keeps a tank hot by burning natural gas or LPG. Solar replaces much of that purchased fuel with direct solar heat and uses a booster only when solar contribution is not enough.
Reduce Gas Consumption
Strong solar contribution can substantially reduce how often purchased gas or another booster energy source is needed for water heating.
Use Direct Solar Heat
Collectors capture solar energy specifically for heating water rather than converting sunlight into household electricity first.
Potential STCs
Eligible listed solar water-heater systems can create Small-scale Technology Certificates when installed in the approved configuration.
Keep Stored Hot Water
The household keeps a familiar stored reserve rather than changing to continuous-flow delivery.
Quiet Renewable Option
Solar thermal avoids the compressor and large fan used by heat-pump systems, which can matter near bedrooms or close boundaries.
Potentially Retire Hot-Water Gas
If hot water is the last gas appliance and the solar system uses electric boosting, the broader gas connection can be considered separately.
One Big Advantage: You Already Have a Storage Tank Site
Gas storage already gives the property the physical space, water services and often drainage associated with a full-sized cylinder. That can help a split-solar conversion and makes heat pump especially easy to compare.
Tank Footprint Already Exists
The home is already accustomed to a ground-level cylinder, so a split-solar tank may fit naturally if the dimensions and clearances suit.
Hot & Cold Services Are Nearby
Existing water services can often form part of the new installation, although connection points may need to be altered.
Drainage May Already Help
Existing relief drainage can be useful, subject to the new system's requirements and current installation standards.
Heat Pump Uses the Same Advantage
If the location also has suitable airflow, noise separation and electrical access, the same tank site can make a heat pump a very natural gas-free alternative.
Split Solar Adds Roof Pipework
The ground-level cylinder must be connected to roof collectors, so the practical solar pipe route matters.
Close-Coupled Solar Changes the Site
Moving the tank onto the roof can free the old gas-storage footprint but adds structural loading and roof-access considerations.
Already Have Solar PV? Heat Pump Becomes a Very Strong Comparison
Solar thermal and solar PV are different technologies. If the home already has useful PV capacity, a heat pump can use that electricity efficiently without adding a second collector platform dedicated only to hot water.
Gas Storage
Rooftop PV cannot directly power the gas burner, so the existing hot-water system remains dependent on natural gas or LPG.
Solar Thermal
Dedicated collectors directly heat the water but occupy their own roof area and add roof-specific installation and servicing requirements.
Heat Pump + PV
A heat pump can run during solar-production hours and use far less household electricity than conventional resistance heating while removing gas from normal hot-water operation.
If rooftop PV already occupies the best solar area and the existing gas-storage tank site is suitable for a heat pump, we would usually favour heat pump over adding separate solar-thermal collectors. The more marginal the collector roof becomes, the stronger that recommendation gets.
Split Solar or Close-Coupled Solar After Gas Storage?
Both can work, but they use the existing gas-storage site very differently.
Ground-Level Tank + Roof Collectors
This is often the most natural physical conversion from gas storage because the new solar cylinder can potentially occupy a similar ground-level area. Solar flow and return pipework then connects the cylinder to the collector array on the roof.
- Can reuse the idea of an existing tank position.
- Keeps the heavy stored-water mass at ground level.
- Needs a practical collector pipe route.
- Still requires suitable roof exposure.
Tank + Collectors on the Roof
This moves the storage cylinder onto the roof with the collectors and can free the ground-level gas-storage position, but roof structure, loading, pitch, access and servicing become much more important.
- Can reclaim ground space.
- Places tank weight on the roof.
- Requires suitable roof structure and safe access.
- Future servicing is roof based.
What Happens to the Existing Gas Connection?
The gas branch serving the old storage heater needs to be safely isolated or altered. Whether the property keeps its broader natural-gas or LPG supply depends on what else still uses gas.
The Property Gas Supply Can Stay
Cooktops, fireplaces and other appliances can continue using gas. Only the redundant hot-water branch 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 remove an ongoing gas service charge, but removing the water heater 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. Gas storage did not depend on solar exposure; solar thermal does.
Usable Roof Area
Enough practical roof space is needed for the collector configuration required by the household and selected system.
Solar Exposure
Collector position and available sunlight directly affect how much useful solar heat the system can contribute.
Shading
Trees, nearby buildings and roof structures can materially reduce the performance potential of the collector area.
Roof Access
Height, pitch, material and safe access can affect installation complexity, cost and future servicing.
Roof Loading
A close-coupled system places 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 strengthen the argument for a heat pump instead of adding a separate thermal collector array.
What Happens When the Sun Is Not Providing Enough Heat?
Solar hot water still needs a backup heat source for extended poor weather, high household demand or periods when collector contribution is not enough.
Electric Boosting
An electric booster allows the home to remove gas from normal hot-water operation while still providing backup heating when solar contribution falls short.
Gas Boosting
Some solar configurations can retain gas backup, but that works against the broader goal if the homeowner is deliberately trying to reduce or eliminate gas.
Sizing Matters
Tank capacity, collector area and household usage all influence how often the booster needs to operate.
When Solar Hot Water Is the Stronger Upgrade
Solar deserves the strongest recommendation when the property itself gives direct solar thermal a clear advantage.
Excellent Sunny Roof
Strong, unshaded collector exposure is the foundation of a genuinely good solar-hot-water installation.
You Specifically Want Direct Solar Thermal
If the goal is to heat water directly from the sun rather than use a refrigeration cycle, solar is the clear renewable pathway.
Quiet Operation Matters
Solar avoids a heat-pump compressor and large fan, which can be important in noise-sensitive locations.
Roof Access Is Straightforward
Good access reduces installation complexity and makes future collector servicing more manageable.
Ground Space Should Be Reclaimed
A suitable close-coupled system can move the tank onto the roof and free the old gas-storage position.
Hot Water Is the Last Gas Appliance
Solar with a non-gas booster can become part of a broader move away from gas, subject to the rest of the property.
When We Would Recommend Heat Pump Instead
Because gas storage already gives you a tank footprint, heat pump becomes the preferred alternative surprisingly quickly when solar thermal does not have a clear roof advantage.
Rooftop PV Already Exists
The home already has a solar-electric platform that can power efficient water heating during the day.
Roof Is Shaded or Crowded
Heat pump does not depend on dedicated sunny collector area in the way solar thermal does.
Roof Access Is Difficult
Keeping the hot-water equipment at ground level avoids collector installation and servicing on a difficult roof.
The Existing Tank Site Is Good
An outdoor gas-storage position can often be a very practical heat-pump site if airflow, noise, drainage and electrical access suit.
You Want Simpler Future Servicing
Heat-pump components are generally serviceable from ground level rather than split between tank and roof collectors.
The Choice Is Close
Where both technologies are technically possible but solar has no clear roof or noise advantage, we would usually favour heat pump.
Can Gas-Storage-to-Solar Qualify for STCs?
Eligible listed solar water heaters can create Small-scale Technology Certificates when the exact system and completed installation meet the current scheme requirements. Eligible air-source heat pumps can also qualify.
Eligible Listed Solar Systems Can Qualify
The collector, tank and complete approved configuration must match the registered model and installation requirements.
Eligible Heat Pumps Can Qualify Too
Do not assume solar has an incentive advantage simply because it uses roof collectors. Both eligible technologies can participate in the federal STC scheme.
Confirm the Claim Pathway Before Installation
Product eligibility alone does not complete an STC or state incentive claim. Confirm the installer, registered agent and any pre-approval requirements before installation.
Current Gas Storage Starting Price vs a Solar Conversion
A like-for-like gas-storage replacement can be simpler upfront, while solar adds collectors, mounting and roof work in exchange for reduced reliance on purchased fuel. Compare the complete installed scope rather than appliance price alone.
Usually the simplest pathway where the existing gas supply, tank location and fuel choice remain suitable.
Current Installed Today gas collection starting price. Final gas-storage pricing depends on model, fuel type, size and installation scope.
Best where collector exposure is genuinely strong and the homeowner specifically wants direct solar thermal or a very quiet renewable system.
Allow for collectors, mounting, roof access, solar pipework, booster requirements and any changes to the existing tank position or services.
Often the stronger choice where the existing tank site is good but the roof is shaded, crowded, difficult or already valuable for PV.
Current Installed Today heat-pump collection starting price. Final value depends on product, location and selected installation scope.
How a Gas-Storage-to-Solar Conversion Usually Works
The exact scope depends on split or close-coupled solar and whether gas remains elsewhere in the property.
Assess the Roof
Check solar exposure, shading, collector area, roof material, structure and safe access.
Choose the Solar Layout
Decide whether to use the existing ground-level tank concept with split solar or move the system onto the roof.
Confirm Booster & Gas Changes
Choose electric or gas boosting, then confirm how the redundant gas hot-water branch and any electrical supply will be handled.
Install & Commission
Remove the old gas tank, install the solar tank and collectors, complete services and drainage, then commission the complete system.
Supply Only vs Supplied & Installed
Installed Today sells hot-water products online with supply-only ordering across supported Australian metro areas and supplied-and-installed options where available in eligible Brisbane and Gold Coast service areas. Solar conversions can involve roof work, gas changes and system-specific installation requirements beyond a standard gas replacement.
Confirm the Full Solar Layout First
Arrange appropriately licensed trades to confirm collector position, tank layout, booster, gas work, plumbing, roof work and incentive pathway before purchasing the system.
Availability Depends on Product & Location
Where an Installed Today installation option is offered, review the product's installation inclusions and any additional roof, gas, electrical, plumbing or relocation work required for the property.
Gas Storage to Solar Hot Water FAQs
Can I replace gas storage with solar hot water?
Yes. Natural-gas or LPG storage can be replaced with split or close-coupled solar hot water where the roof, tank position, services, booster and installation conditions suit the selected system.
Is solar hot water better than gas storage?
Solar can substantially reduce reliance on purchased fuel when the roof has strong solar exposure and the system is correctly sized. Gas storage can be simpler to replace like for like, but Australian Government guidance describes gas storage systems as particularly inefficient because of storage heat losses.
Should I choose solar or a heat pump?
Solar is strongest on an excellent sunny roof when direct solar thermal or quieter operation is specifically wanted. Heat pump is usually stronger where rooftop PV already exists, roof space or access is limited, or the existing ground-level gas-storage site is already well suited to a heat pump.
Can I reuse the existing gas-storage tank position?
Potentially with split solar. The base, footprint, plumbing, drainage, service clearances and booster arrangement still need to suit the selected solar cylinder.
What happens to the old gas connection?
The gas branch serving the old storage heater needs to be safely isolated or altered. If other gas appliances remain, the broader gas supply can stay. If hot water was the last gas appliance, broader disconnection can be considered separately.
Does solar hot water still need a booster?
Yes. Solar hot water needs backup heating for periods when solar contribution is insufficient. The booster may be electric or gas depending on the selected system and household strategy.
What if I already have rooftop solar PV?
Existing PV strengthens the heat-pump comparison because a heat pump can use household-generated electricity without adding a separate solar-thermal collector array. Solar thermal can still make sense if roof area remains excellent and direct solar heating is specifically preferred.
Can gas-storage-to-solar replacement qualify for STCs?
Eligible listed solar water-heater systems can create STCs when installed in the approved configuration within the model's eligibility period and all scheme requirements are met.
Should I choose split solar or close-coupled solar?
Split solar is often the more natural conversion from gas storage because the home already has a ground-level tank site. Close-coupled solar can free ground space but places the tank and collectors on the roof.
When would you recommend heat pump instead of solar?
Heat pump is usually the stronger first comparison when rooftop PV already exists, collector exposure is only average, roof space or access is limited, or the existing outdoor gas-storage site is already well suited to a heat pump.
Replacing Gas Storage? Let the Roof Decide Whether Solar Wins
Gas-storage-to-solar can be an excellent upgrade where the roof is genuinely strong and direct solar thermal is the goal. But because you already have a full-sized tank site, a heat pump is usually the first alternative to compare. If the roof is shaded, crowded with PV, difficult to access or simply average, we would generally favour the heat pump rather than force a solar-thermal conversion.
