Choosing between a heat pump and solar hot water system is one of the most common decisions Perth homeowners face when upgrading from an old electric or gas system. Both technologies offer significant savings over traditional systems, but they work very differently and suit different homes.
The Quick Comparison
| Factor | Heat Pump | Solar Hot Water |
|---|---|---|
| Upfront Cost (Fully Installed) | $2,900 - $5,000 | $4,400 - $7,000+ |
| Running Cost (Perth) | $300 - $450/year (Or under $100 with timers) | $150 - $300/year |
| Govt. Incentives (2026) | Federal STCs (Rebate value decreases Jan 1 each year) | Federal STCs (Higher rebate for efficient models) |
| Space Required | Outdoor unit (similar to AC compressor) | Roof panels + Ground tank (Split) or Roof tank |
| Noise Level | 37dB - 55dB (Hum like a fridge/AC) | Silent |
| Lifespan | 10 - 15 years | 15 - 20+ years |
| Best For | Shaded roofs, quick replacements, renters | North-facing roofs, long-term owners |
How Each System Works
Heat Pump Hot Water
A heat pump works like a reverse air conditioner. It extracts heat energy from the surrounding air and transfers it to water in a storage tank. This process is remarkably efficient—for every 1 kWh of electricity used, a heat pump delivers 3-4 kWh of heating energy.
Key characteristics:
- Works 24/7: Extracts heat day or night, regardless of sunlight.
- Perth Efficiency: Operates efficiently in temperatures from -5°C to 45°C, making it perfect for WA’s mild winters.
- Brands to Watch: We frequently install units from iStore and Reclaim Energy. The Reclaim CO2 heat pump is particularly notable for being “whisper quiet” and working without an electric booster element.
- Programmable Timers: Modern units can be set to run only during the day.
Solar Hot Water
Solar hot water systems use roof-mounted collectors to capture heat from the sun. The heated water is stored in a tank, which can be roof-mounted (thermosiphon) or ground-mounted (split system). Most systems include an electric or gas booster for cloudy days.
Key characteristics:
- Direct Solar Gain: Uses free solar energy during daylight hours.
- Roof Real Estate: Requires suitable north-facing roof space.
- Collector Types:
- Flat Plate: Great for most Perth suburbs.
- Evacuated Tube: More efficient in cooler areas (like the Perth Hills) or for east/west facing roofs.
- Booster Reliance: Will automatically switch to grid electricity or gas when water temperature drops below 60°C.
Cost Comparison in Detail
Upfront Costs
Heat pump systems generally offer a lower entry price. In 2026, a quality 270L system typically costs between $2,900 and $5,000 fully installed. The lower end includes budget-friendly models, while premium units like the Sanden Eco Plus or Reclaim sit at the higher end.
Solar hot water systems are a bigger initial investment. Expect to pay $4,400 to $7,000+ for a quality split system (like a Solahart or Rheem Loline). Roof-mounted “thermosiphon” units are slightly cheaper but require a structurally sound roof to hold the heavy water tank.
Insider Tip: Both systems qualify for Small-scale Technology Certificates (STCs), which act as an upfront discount. However, the number of STCs drops every January 1st as the scheme phases out towards 2030. Delaying your installation until next year could cost you ~$400-$500 in lost rebates.
Running Costs & The “Synergy Midday Saver” Hack
Heat pumps cost approximately $300-$450 per year to run if left on default settings. But here is the secret many installers miss: if you switch to the Synergy Midday Saver tariff, you pay around 8.4 cents per kWh between 9 am and 3 pm.
By putting your heat pump on a simple timer to run only during this “Super Off-Peak” window, you can drop your annual running cost to under $100.
Solar hot water costs approximately $150-$300 per year. The sun provides 70-90% of your energy for free. You only pay for the booster on cloudy days or during heavy winter usage.
Long-Term Savings
Over a 15-year period, the numbers tell an interesting story:
| System | Purchase Cost | Running Cost (15 years) | Total Cost of Ownership |
|---|---|---|---|
| Electric Storage | $1,700 | $21,000 | $22,700 |
| Heat Pump (Standard) | $3,500 | $5,625 | $9,125 |
| Heat Pump (Smart Timer) | $3,500 | $1,500 | $5,000 |
| Solar Hot Water | $5,500 | $3,375 | $8,875 |
Costs are estimates based on 2026 Perth electricity rates. Smart Timer calculation assumes 8.4c/kWh tariff.
Heat pumps on a timer are currently the most cost-effective option for many Perth households, edging out traditional solar hot water in total lifecycle value.
Installation Requirements
Heat Pump Requirements
Heat pumps are relatively simple to install, often called a “plumber’s delight” because they don’t require a roof team.
Space: You need a well-ventilated spot. The unit blows out cold air, so don’t place it facing a wall less than 1 meter away. Electrical: Most 270L units run on a standard 10amp circuit, meaning existing wiring usually works fine. Noise Considerations: Under the Environmental Protection (Noise) Regulations 1997, noise at your neighbor’s boundary must not exceed 35 dB(A) after 10 pm. Placement Tip: Avoid placing the unit outside a bedroom window. If you must, choose a premium quiet model like the Reclaim (37dB) rather than a louder budget model (50dB+).
Solar Hot Water Requirements
Solar systems involve more complex logistics.
Roof Suitability:
- Orientation: North is best. West is okay. East is marginal. South is a no-go.
- Shading: One shaded panel can drop the efficiency of the whole system. Watch out for rapid gum tree growth or new two-story builds next door.
- Structural Load: A roof-mounted tank weighs 300kg+ when full. Older timber-framed homes in suburbs like Victoria Park or Fremantle may need roof reinforcement, adding $500+ to the cost.
Plumbing and Electrical:
- Requires piping from the ground to the roof.
- Split systems need a sensor wire run between the roof panels and the ground tank.
Perth Climate Considerations
Perth’s climate suits both technologies well, but in different ways.
Heat Pumps in Perth
Our mild winters are a huge advantage. Heat pumps lose efficiency as the air gets freezing, but Perth’s average winter low of 8°C is well within the “sweet spot” for these machines. They work happily down to -5°C or -10°C, so our climate is a walk in the park for them.
Solar Hot Water in Perth
We live in one of the sunniest cities in the world. Perth averages 8-9 hours of sunshine daily. This means a solar system here will require far less boosting than one in Melbourne or Hobart.
The catch: Perth has “hard” water in many suburbs. High mineral content can eat through the copper pipes in solar collectors and the vitreous enamel in tanks. If you are in a coastal area like Cottesloe or Scarborough, salt corrosion is also a factor. In these zones, we recommend stainless steel tanks (like those from iStore or specific Rheem models) over mild steel to double the system’s life.
Which System Suits Which Home?
Heat Pumps Are Better When:
- ✅ You have solar PV panels: You can use your own excess solar power to run the heat pump for “free.”
- ✅ Your roof is complicated: If you have gables, shading, or slate tiles, avoiding roof work saves money and headaches.
- ✅ You want a quick swap: If your old tank bursts on a Tuesday, a heat pump can be installed by Wednesday afternoon. Solar often takes longer to plan.
- ✅ You are on a budget: The lower upfront cost helps cash flow.
Solar Hot Water Is Better When:
- ✅ You have a large family: Solar tanks (300L+) often have high recovery rates for back-to-back showers.
- ✅ You want “set and forget”: A high-quality solar system (like a Solahart) can sit on a roof for 20 years with minimal fuss.
- ✅ Gas is your only backup: If you have a gas connection but no solar PV, a gas-boosted solar system is extremely efficient.
- ✅ Roof space is abundant: You have a clear, north-facing roof doing nothing.
Maintenance Comparison
Heat Pump Maintenance
- Clean the Filters: Just like your AC, the air intake filter needs a quick hose down every 3-6 months.
- Pressure Relief Valves: Pull the lever every 6 months to prevent seizing (a common failure point in WA).
- Tank Flush: Drain a few liters annually to remove sediment.
Solar Hot Water Maintenance
- Anode Replacement: This is critical. The “sacrificial anode” inside the tank prevents rust. In Perth, check this every 5 years. If it dissolves completely, your tank will rust out shortly after.
- Panel Cleaning: Usually, rain does this for you. But if you live near a busy road (like Leach Hwy or the Mitchell Fwy), pollution buildup might need a hose down every year.
- Pump Check: Split systems have a small circulation pump that can wear out after 8-10 years.
Common Questions
Can I switch from one to the other later?
Yes, but it’s expensive. Switching from solar back to a heat pump means removing heavy panels and patching roof tiles. It is better to make the right call now.
Which is quieter?
Solar hot water is silent. Heat pumps make a low hum. For context, a whisper is 30dB, a fridge is 40dB, and a standard conversation is 60dB. Most modern heat pumps sit around 45-50dB.
Which has better resale value?
Solar panels on the roof are a visible “green” asset that buyers recognize instantly. Heat pumps are less visible but are becoming a known value-add for energy-conscious buyers looking for a modern, gas-free home.
What about split-system solar with heat pump boosting?
This exists (combining solar thermal panels with a heat pump compressor) but is rare and expensive ($7,000+). For most Perth homes, a standard heat pump powered by rooftop solar PV panels is a smarter, more flexible financial move.
Our Recommendation Approach
We don’t push one technology over the other. Our free assessments consider:
- Roof Orientation: Does your roof actually face North?
- Shading: Will that neighbor’s extension block your winter sun?
- Tariff Setup: Are you on the Synergy Midday Saver or a standard flat rate?
- Household Size: Do you need 2 showers a day or 12?
- Water Quality: Are you in a hard water or coastal zone?
Based on these factors, we recommend the system that makes most sense for your situation. Both heat pumps and solar hot water are excellent technologies that will save you money compared to traditional systems.
Getting Started
If you’re considering either system, start with a free assessment. We’ll inspect your property, discuss your needs, and provide quotes for suitable options. This allows you to compare both technologies for your specific situation.
Contact us to arrange your free assessment—we’ll help you choose the right system for your Perth home.