Heat Pump to Solar Hot Water
Heat Pump to Solar Hot Water: Should You Switch?
Solar hot water can remove the heat-pump compressor and use direct solar thermal energy — but changing technology should give your home a real advantage.
A heat-pump hot-water system can be replaced with either split or close-coupled solar hot water where the roof, household demand and installation conditions suit. The change introduces roof collectors, a booster strategy and potentially a different tank location. If the existing heat-pump position already works well, compare a modern replacement heat pump before adding an entirely new solar-thermal system to the roof.
Does Solar Make Sense Here?
Solar can be excellent, but roof suitability and the reason you are leaving heat pump matter more than simply choosing another renewable technology.
1 Why are you considering solar?
2 What is the roof like?
3 What matters most?
Guide only. Roof orientation, shading, roof structure, access, collector area, tank position, booster requirements, household demand and the existing heat-pump installation all need to be checked.
Can You Replace a Heat Pump With Solar Hot Water?
Yes. A heat-pump hot-water system can be replaced with solar hot water where the property has suitable roof area, solar exposure and installation access. The main change is that water heating moves from extracting heat from ambient air to collecting thermal energy through roof-mounted solar collectors, with a booster supporting the system when solar contribution is not sufficient.
Roof Collectors
Solar thermal collectors need suitable roof area, orientation, exposure, access and installation conditions.
Tank Layout
Split solar keeps a tank at ground level, while close-coupled solar places the storage cylinder together with the collectors on the roof.
Booster
Solar hot water normally needs a backup heating method for periods when available solar contribution is not enough.
Existing Heat-Pump Services
Your current tank position, plumbing, drainage and electrical infrastructure may already make another heat pump comparatively straightforward.
What Actually Changes When You Move From Heat Pump to Solar?
Both systems are efficient storage hot-water technologies, but they collect energy in completely different ways. The biggest change is moving part of the hot-water installation onto the roof.
Compressor & Fan Are Removed
The heat-pump refrigeration section is removed, so the replacement no longer relies on a heat-pump compressor and fan to collect heat from ambient air.
Solar Collectors Are Added
Roof-mounted flat-plate or suitable solar collector equipment is introduced to capture thermal energy from sunlight.
Solar Pipework Is Added
The solar installation needs the required flow-and-return or thermosiphon arrangement between the collector area and stored hot water.
Booster Strategy Changes
The new solar system needs a suitable backup heating strategy for periods when solar contribution alone does not meet household demand.
Roof Access Matters
Roof pitch, material, building height, access and collector installation conditions become part of the hot-water job.
Heat-Pump Airflow No Longer Matters
The new system does not need the same compressor airflow requirements as a heat pump, although solar has its own roof and tank-location requirements.
Split Solar or Close-Coupled Solar After a Heat Pump?
This is one of the biggest decisions on the conversion. Your existing heat-pump position can make split solar especially logical because a ground-level storage location already exists.
Ground Tank + Roof Collectors
Split solar keeps the storage cylinder at ground level and places only the solar collectors on the roof.
This can align well with a former heat-pump site because the existing tank position, water connections and drainage may already be useful.
A circulation system moves heat between the collector array and storage tank depending on the solar design.
Tank + Collectors on the Roof
A close-coupled system places both the tank and collector assembly on the roof and commonly uses thermosiphon circulation.
That can free the ground-level area previously occupied by the heat pump, but roof loading, access and structural suitability become more important.
This layout can be attractive where reclaiming ground space matters and the roof is particularly well suited.
Why Change From Heat Pump to Solar Hot Water?
There are genuine reasons to choose solar thermal. The strongest cases are where the property and customer's priorities specifically suit what solar does differently.
Remove Heat-Pump Compressor Noise
Solar hot water does not use a heat-pump compressor and outdoor fan. This can matter where the only practical tank position is particularly noise sensitive.
Use Direct Solar Thermal Energy
The collectors capture heat from sunlight specifically for the household hot-water system rather than first converting sunlight into electricity.
Reclaim Ground Space
A suitable close-coupled solar system can move the storage tank onto the roof and free the area currently occupied by the heat pump.
Replacement Heat Pump vs Solar: Current JR Starting Prices
Both are efficient hot-water technologies, but the installed scope can be very different. These cards read JR's current advertised starting prices from the live collections when the page loads.
Keeps the existing efficient electric pathway and may reuse much of the current tank position, plumbing, drainage and electrical infrastructure.
Eligible systems may qualify for JR's current upfront STC pathway.
Adds dedicated solar-thermal roof collectors and can provide very low purchased energy use when the property and system are well matched.
Eligible solar systems may also qualify for JR's current upfront STC pathway.
Heat Pump vs Solar Hot Water
| Consideration | Heat Pump | Solar Hot Water |
|---|---|---|
| How heat is collected | Extracts heat from surrounding air using a refrigeration cycle | Roof collectors absorb thermal energy from sunlight |
| Storage | Ground-level storage tank in most domestic installations | Ground-level tank with split solar or roof-mounted tank with close-coupled solar |
| Roof equipment | No dedicated solar-thermal collectors required | Dedicated solar collectors required |
| Operating noise | Compressor and fan operate while heating | No heat-pump compressor; split solar may use circulation equipment |
| Rooftop solar PV | Can directly use household-generated PV electricity | Solar thermal collectors use roof area separately from PV panels |
| Booster | System-dependent electric booster or heating mode | Backup heating supports periods of insufficient solar contribution |
| STCs | Eligible listed systems may qualify | Eligible listed systems may qualify |
| Installation advantage | Existing heat-pump site may already suit replacement | Excellent roof conditions can provide strong direct solar contribution |
Is Your Roof Actually Suitable for Solar Hot Water?
Roof suitability is one of the biggest differences between replacing a heat pump and converting to solar. A heat pump can work without dedicated collector roof area; solar thermal cannot.
Usable Roof Area
The home needs enough clear roof space for the required collector configuration without creating impractical conflicts with other roof equipment.
Orientation & Solar Exposure
Collector position and expected sunlight influence how much useful solar heat the system can capture.
Shading
Trees, neighbouring buildings, roof structures and other obstacles can reduce available solar exposure.
Roof Access
Roof pitch, height, material and general access can materially affect installation complexity and future servicing access.
Roof Loading
Close-coupled systems place both collectors and stored water on the roof, so structural suitability is particularly important.
Existing Solar PV
A roof already covered with productive PV panels may have limited practical space remaining for a dedicated solar-thermal collector array.
Already Have Solar PV? That Changes the Heat Pump vs Solar Comparison
Solar PV and solar hot water both use sunshine, but they use the roof in different ways. A heat pump can consume electricity already produced by your PV system, while solar hot water needs its own dedicated thermal collectors.
Heat Pump + Solar PV
The heat pump can be scheduled through daylight hours so excess household PV generation contributes directly to heating the stored water.
Solar Thermal
Dedicated collectors absorb sunlight as heat specifically for the hot-water system rather than generating electricity for general household use.
Roof Space Has Value
Solar thermal uses collector area that could otherwise potentially be available for additional PV, depending on the property and future energy plans.
If the home already has a strong PV system and the current heat-pump position works well, heat pump can remain a very clean energy pathway without adding another dedicated solar system to the roof.
If Your Heat Pump Failed, Does That Mean Solar Is the Better Replacement?
Not automatically. A failed appliance and an unsuitable technology are two different things. Current heat pumps vary widely in noise, recovery, controls, warranty, service support and overall build quality.
Tank Position Is Already Proven
If the old heat pump operated in the current location for years, the property has already demonstrated that it can physically accommodate a heat-pump installation.
Plumbing Is Already There
Existing hot and cold services, valves, drainage and storage-system space may all reduce the amount of redesign required.
Electrical Infrastructure Exists
The existing supply still needs to be checked against the selected replacement model, but the property is already configured around electric heat-pump hot water.
Do Heat Pumps and Solar Hot Water Both Qualify for STCs?
Eligible listed solar water heaters and eligible air-source heat pumps can both create Small-scale Technology Certificates when the exact system and completed installation satisfy current scheme requirements.
Eligible Replacement Systems Can Qualify
The exact heat-pump model and configuration need to appear on the current eligible register and be installed in accordance with its listed configuration.
Eligible Solar Systems Can Also Qualify
Solar hot-water eligibility also depends on the exact listed model, installation date, location and completed configuration.
When Heat Pump to Solar Can Genuinely Make Sense
Solar should provide a clear benefit rather than simply being another efficient technology.
Compressor Noise Is the Main Problem
If a suitable quiet heat pump or relocation cannot solve a genuine noise problem, solar removes the heat-pump compressor and fan from the hot-water system.
Excellent Unshaded Roof
A home with strong solar exposure, appropriate collector space and straightforward roof access can be very well suited to solar thermal.
Direct Solar Heating Is Preferred
Some homeowners specifically prefer dedicated solar-thermal water heating rather than relying on a refrigeration-cycle appliance.
Ground Space Is Valuable
Where the roof is suitable for close-coupled solar, moving the storage cylinder onto the roof can free the current heat-pump location.
Roof Layout Already Suits Solar
Existing roof design, orientation and access may make the solar installation unusually straightforward.
Solar Thermal Is the Customer's Preference
Where the property suits it and the homeowner understands the installation and servicing differences, solar remains a strong renewable hot-water technology.
When We Would Usually Stay With Heat Pump
If the current site already works and there is no specific reason to add solar-thermal equipment to the roof, replacing the existing heat pump with another suitable heat pump is often the more straightforward pathway.
The Heat Pump Simply Failed
A failed unit does not mean the technology is wrong for the property, particularly where the location has otherwise worked successfully.
Lowest Installed Cost Matters
Reusing an established heat-pump position can avoid the additional roof collectors and solar installation work involved in a full technology conversion.
Roof Area Is Limited or Shaded
A heat pump does not rely on dedicated solar collector exposure and may therefore suit properties with compromised roof conditions better.
Solar PV Already Uses the Roof
A heat pump can make use of electricity generated by the existing PV system without requiring another dedicated collector array.
Tank Position Already Works
Existing plumbing, electrical supply, drainage, base and service access can all make a replacement heat pump easier to integrate.
Future Roof Access Is Difficult
Keeping the active hot-water equipment at ground level can reduce the amount of dedicated hot-water equipment that needs roof access.
How a Heat-Pump-to-Solar Conversion Works
Confirm Why You Are Changing
Determine whether the driver is compressor noise, roof preference, direct solar thermal heating or simply a failed heat pump.
Assess the Roof
Check usable collector area, orientation, shading, pitch, roofing material, structural considerations and safe installation access.
Choose Split or Close Coupled
Decide whether the storage tank should remain at ground level or move onto the roof with the collectors.
Size Tank & Collectors
Match storage capacity and collector area to household occupancy, bathrooms, usage and expected solar contribution.
Remove the Heat Pump
Isolate and remove the old heat-pump system, then alter the existing water, electrical and drainage services as required.
Install & Commission Solar
Install the selected tank, collectors, solar pipework, valves, booster and controls, then commission the complete system.
Heat Pump to Solar Hot Water FAQs
Can I replace a heat pump with solar hot water?
Yes. A heat-pump hot-water system can be replaced with solar hot water where the roof, collector position, storage layout and household demand suit the installation.
Is changing from heat pump to solar hot water worth it?
It can make sense where the property has an excellent solar roof and the homeowner specifically values direct solar thermal heating, wants to remove the heat-pump compressor or wants a close-coupled system to free ground space. If the existing heat-pump installation still works well, another heat pump should normally be compared first.
Is solar hot water cheaper to run than a heat pump?
Both can provide low purchased-energy hot water. Solar performance depends on solar contribution and booster use, while heat-pump running cost depends on efficiency, tariffs, household demand and whether rooftop solar PV is available.
Is solar hot water quieter than a heat pump?
Solar hot-water systems do not use the compressor and outdoor fan found in a heat pump. Split solar designs may use circulation equipment, while many close-coupled systems use thermosiphon circulation.
Should I choose split or close-coupled solar?
Split solar generally keeps the storage tank at ground level and may make good use of the existing heat-pump location. Close-coupled solar places the tank and collectors on the roof and can free the old ground-level tank area. Roof suitability, access and household needs determine which layout fits better.
Can split solar use the same position as my heat-pump tank?
Often it can provide a useful starting point. The existing base, water services, drainage, available space and solar pipe routing still need to suit the selected split-solar system.
Can I move the replacement tank onto the roof?
A suitable close-coupled solar system can place both the tank and collectors on the roof. Roof structure, access, pitch, material and the selected system all need to be assessed before choosing that layout.
What happens to the existing heat-pump electrical circuit?
The existing electrical arrangement needs to be checked against the new solar system's booster and control requirements. Some infrastructure may be useful, while other parts may need alteration.
Do solar hot-water systems still need a booster?
Solar systems normally include a backup heating method to support the household when available solar contribution is not sufficient for the required hot-water demand.
What if my roof is shaded?
Significant shading can reduce useful solar exposure and may make dedicated solar thermal less attractive. A heat pump does not require dedicated sunny collector roof area and can therefore be a stronger option on some shaded properties.
What if my roof is already covered in solar PV?
Solar thermal needs its own collector area, while a heat pump can use electricity already produced by the existing PV system. Available roof space and future PV plans should therefore be considered before replacing heat pump with solar hot water.
Is solar thermal the same as solar PV?
No. Solar hot-water collectors capture heat specifically for the water-heating system. Solar PV panels generate electricity that can power household loads, including a heat pump.
Do heat pumps and solar hot water both qualify for STCs?
Eligible listed air-source heat pumps and eligible listed solar water heaters can qualify for Small-scale Technology Certificates when the exact system and completed installation meet current scheme requirements.
Does JR's $1,000 upfront STC discount apply to solar too?
JR's current policy applies the $1,000 including GST upfront STC discount to eligible heat-pump and solar-hot-water systems supplied and installed by JR, subject to final STC eligibility and assignment requirements.
Should I just replace my failed heat pump with another heat pump?
If the existing tank location works, the roof is not especially suited to solar thermal and the only problem is that the old appliance has failed, another heat pump should normally be compared first because much of the existing installation infrastructure may remain useful.
Thinking About Moving From Heat Pump to Solar? Compare the Complete Job
Solar hot water can be an excellent choice on a strong, unshaded roof and can remove the heat-pump compressor from the property. If your existing heat-pump location already works, compare a modern replacement heat pump as well — particularly if rooftop PV already exists, roof space is limited or keeping installation complexity down matters.