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When it's time to replace your hot water system, one question comes up more than any other: should I go tankless or stick with a tank?
Both systems heat water effectively — but they do it differently, cost differently to run, and suit different households. On the Gold Coast, where both gas and electricity options are widely available, the choice is genuinely open. Here's how they compare, in plain terms.
What's the Difference?
Tank (storage) systems
heat water and store it at a set temperature in an insulated tank, ready to use whenever you turn on the tap. Electric storage, gas storage, heat pump, and solar hot water all fall into this category.
Tankless (continuous flow / instantaneous) systems
have no storage tank. They heat water on demand the moment a tap is opened, using a gas burner or electric elements to bring water up to temperature as it flows through the unit.
The core trade-off is this: tanks trade storage space for consistent supply; tankless systems trade a tank for potentially unlimited supply — but only up to their flow rate.
Cost Comparison
Upfront Cost (Installed, Gold Coast 2026)
| System | Estimated Installed Cost |
|---|---|
| Electric storage (250L) | $1,200–$1,900 |
| Gas storage (260L) | $1,600–$2,400 |
| Continuous flow gas (20L/min) | $1,600–$2,600 |
| Heat pump (250–270L) | $1,700–$3,500 (after rebates) |
| Solar hot water (300L) | $1,800–$3,800 (after rebates) |
| Electric continuous flow* | $800–$1,400 |
*Electric continuous flow systems draw very high current and require significant electrical infrastructure upgrades in most homes — often making them cost-prohibitive.
Running Costs (Annual, 4-person household estimate)
| System | Estimated Annual Running Cost |
|---|---|
| Electric storage (peak rate) | $800–$1,100 |
| Electric storage (off-peak, Tariff 33) | $400–$600 |
| Gas storage | $280–$420 |
| Continuous flow gas | $260–$400 |
| Heat pump | $130–$220 |
| Solar hot water | $60–$160 |
Continuous flow gas running costs are similar to gas storage — the difference is that continuous flow only heats water you actually use, while storage tanks maintain temperature around the clock (with some standby heat loss).
Hot Water Supply: Does Tankless Really Deliver Unlimited Hot Water?
This is where tankless systems are often oversold. "Unlimited hot water" is only true if your demand stays within the system's flow rate capacity — measured in litres per minute (L/min).
- A 16L/min unit can typically supply one shower at a time comfortably
- A 20L/min unit suits one shower + tap/kitchen use simultaneously
- A 26L/min unit can handle two showers running at once
If demand exceeds the flow rate, water temperature drops. With a well-sized tankless system, this rarely happens. But in households with simultaneous high demand — large families, back-to-back morning showers, international-style long showers — sizing matters enormously.
Tank systems
don't have a flow rate limit per se, but they have a storage limit. Once the stored hot water is depleted, you wait for recovery (typically 1–2 hours for electric). Well-sized tanks simply avoid running out.
Head-to-Head Comparison
| Factor | Tank System | Tankless System |
|---|---|---|
| Upfront cost | Lower to moderate | Moderate (gas); high (electric) |
| Running cost | Moderate (gas/electric) — Low (heat pump/solar) | Low–Moderate (gas) |
| Hot water capacity | Limited by tank size | Flow-rate limited but consistent |
| Space required | Tank takes significant space | Very compact wall-mounted unit |
| Installation complexity | Straightforward | Requires gas line or significant electrical work |
| Lifespan | 8–12 years (tank) | 15–20 years |
| Maintenance | Anode replacement, flushing | Burner service, filter cleaning |
| Simultaneous outlets | No limit up to tank capacity | Limited by flow rate |
| Energy efficiency | Electric: low; Heat pump/solar: high | Gas: good; Electric: poor |
| Instant hot water arrival at tap | Depends on pipe distance | Slight delay (system must fire up) |
Which Is Better for Gold Coast Homes?
Tankless (Continuous Flow Gas) Suits You If:
- You want the most compact installation — no tank space needed
- You have a natural gas connection
- Your household has predictable, moderate hot water use
- You value a 15–20 year system lifespan with low maintenance
- You don't want to think about running out of hot water (within capacity)
- You're replacing a system in a unit, townhouse, or home with limited outdoor space
Tank System (Heat Pump or Solar) Suits You If:
- You want the lowest running costs possible
- You have rooftop solar PV or a good north-facing roof
- You have outdoor space for a heat pump or rooftop collectors
- You're happy to take advantage of government rebates
- Your household has high or unpredictable hot water demand (heat pump's larger tank handles this well)
- You want to minimise your carbon footprint
Standard Electric Storage Suits You If:
- You need the lowest upfront cost
- You can access off-peak electricity (Tariff 33) or solar PV
- You're in a rental or property where energy efficiency isn't the primary concern
The Gold Coast Verdict
For most Gold Coast owner-occupiers choosing a new system from scratch in 2026:
- Best overall value: Heat pump (low running costs, rebates, long tank suitability)
- Best for small homes or units: Continuous flow gas (compact, reliable, good lifespan)
- Best for environmentally conscious households with a good roof: Solar hot water
- Best budget option: Electric storage on off-peak tariff
The "vs" framing can be misleading — what matters is matching the system to your household, your property, and your priorities. A licensed plumber can assess your specific situation and make a recommendation.
When to Call a Plumber
All hot water system installation in Queensland requires a licensed plumber. If you're replacing a system or choosing a new type for the first time, Coastal Plumbing Professionals can:
- Assess your current setup and which system type is compatible
- Advise on sizing for your household
- Provide an itemised quote including any gas or electrical connection work
- Handle the full installation and disposal of your old unit
Frequently Asked Questions
Is tankless hot water better than a tank?
Neither is universally better — it depends on your household size, usage pattern, available fuel, and space. Tankless gas systems offer great longevity and consistent supply; tank systems (especially heat pump and solar) offer better energy efficiency.
Does continuous flow gas work in older Gold Coast homes?
Usually yes, if a gas supply is already connected. The plumber will check flue requirements, gas pressure, and pipe sizing before installation.
Can I switch from a tank to a continuous flow system?
Yes, though it typically requires new gas line work and possibly a new flue. Your plumber can advise on the change-over cost at your property.
Is tankless hot water worth the extra upfront cost vs gas storage?
For continuous flow vs gas storage: the price difference is modest and the lifespan advantage (15–20 vs 8–12 years) often makes continuous flow better value long-term.
What happens if the power goes out with a continuous flow gas system?
Most continuous flow gas systems require a small amount of electricity to operate the ignition and controls. A power outage typically means the system won't fire — hot water won't be available until power is restored.
Resources
- Standards Australia AS/NZS 3500 — Plumbing and Drainage
- Energy Rating — Water Heaters Comparison Tool
- Clean Energy Regulator — STCs for Hot Water
- Your Home — Hot Water Systems
- Queensland Building and Construction Commission (QBCC)
