Hot water replacement cost in Wollongong
Wollongong homes built before 2005 are reaching end-of-life on first-cycle hot water systems. Replacement is the biggest single plumbing decision most homeowners make — gas continuous flow runs $2,200–$3,800 installed; electric storage $1,400–$2,400; heat pump $4,200–$6,800 (less after federal STC rebates). Here’s how to choose and what to budget for in Wollongong specifically.
Quick answer — Wollongong hot water replacement cost
| System | Capacity | Install cost | Running cost (annual) |
|---|---|---|---|
| Electric storage (mid-tier) | 250L | $1,400–$2,400 | $650–$950 |
| Gas continuous flow | 26 L/min | $2,200–$3,800 | $420–$680 |
| Gas storage | 170L | $2,400–$3,200 | $520–$780 |
| Heat pump (after STC rebate) | 270L | $2,800–$5,200 | $180–$320 (with solar) / $320–$520 (grid) |
| Heat pump (pre-rebate sticker) | 270L | $4,200–$6,800 | as above |
| Solar hot water (evacuated tube) | 300L | $3,800–$5,600 (after STCs) | $80–$220 |
Which system is right for a Wollongong home?
1. Electric storage — cheapest install, highest running cost
The default Wollongong replacement until 2018–2020. Cheap to buy ($800–$1,400 unit cost), simple to install, mature technology. Downside: it’s the most expensive to run. A 250L unit serving a 4-person household uses 3,500–4,500 kWh/year, costing $650–$950 at current Endeavour Energy tariffs. If your household is on solar + battery, electric storage on a controlled-load tariff makes sense; otherwise, look at heat pump.
2. Gas continuous flow — the Wollongong default since 2015
Wollongong is well-served by natural gas through Jemena Networks, so gas continuous flow has been the dominant replacement choice since 2015. Install runs $2,200–$3,800 depending on wall location, flue requirement, and existing gas-line capacity. Running cost is mid-range — about half electric, somewhat more than heat pump. Best for households without solar where space for a heat pump is limited.
3. Heat pump — the right choice for most new installs in 2026
Heat pumps extract ambient heat from outdoor air to heat water in a storage tank — using roughly one-third the electricity of equivalent electric storage. Wollongong’s mild climate (rarely below 5°C) makes heat pumps highly efficient here; they retain about 90% of rated capacity year-round. The federal STC rebate knocks $1,100–$1,500 off the install. For solar households, running cost is genuinely tiny — $180–$320/yr because the unit runs during the day on free solar.
4. Solar hot water — niche but viable
Direct solar thermal (evacuated tube or flat-plate collector on the roof) is the cheapest to run but expensive to install and complex to maintain. Best for off-grid or remote Wollongong properties (Helensburgh hinterland, parts of Mount Keira). Mainstream households generally pick heat pump instead these days — same effective outcome, simpler maintenance.
Itemised example — Dapto electric-to-heat-pump swap
A real Wollongong install from late 2025. Homeowner in a 4-bed brick Dapto home with rooftop solar replaced a 25-year-old 315L electric storage unit with a 270L heat pump.
| Item | Cost |
|---|---|
| 270L heat pump unit (Sanden, Australian-made) | $4,100 |
| Labour (1 plumber, 1 electrician, 7 hours) | $1,180 |
| Disposal of old electric storage tank | $95 |
| New TPR safety valve and tundish | $155 |
| Condensate drain run and tempering valve | $240 |
| Electrical work (new GPO, RCD test) | $320 |
| Subtotal | $6,090 |
| STC rebate (34 certificates × $38) | −$1,292 |
| TOTAL | $4,798 |
The same household was previously running $1,400/year on their controlled-load electric tariff. Heat pump first-year running cost: $210 (mostly off-peak overnight top-up; solar covered the rest). Annual saving: $1,190. Payback on the “extra” cost over a like-for-like electric replacement: 2.5 years.
Frequently asked questions
What is the federal heat pump rebate worth in 2026?
The Small-scale Technology Certificates (STCs) scheme assigns 25–50 STCs to a 270L heat pump install depending on climate zone. Wollongong sits in Zone 3, which generally yields 30–38 STCs. At ~$38/certificate (May 2026 spot price), that is $1,140–$1,440 off the install cost. The rebate is typically passed through by the installer at point of sale, not claimed by the homeowner. Always ask the installer for the post-STC price.
Is gas still cheaper than electric or heat pump for Wollongong?
Depends on usage. For low-usage households (1–2 people, short showers), gas continuous flow is cheapest to install ($2,200–$3,800) but mid-range to run. For medium-to-heavy usage (3+ people, daily baths), heat pump runs 50–70% lower energy cost than gas but costs more to install. Solar households almost always come out ahead with heat pump because the heat pump runs during the day on free solar electricity.
Why did my plumber recommend replacing the TPR valve and tundish?
TPR (temperature-pressure relief) valves and the tundishes that drain them are wear items — they harden, seize, and fail. Australian Standards require replacement at every hot-water swap. The TPR is a safety device that vents over-pressurised hot water; a stuck TPR is a tank-rupture risk. Costs around $135–$180 fitted. Non-negotiable; do not let an installer skip this.
Can I install a heat pump where my old electric storage was?
Usually yes if the old unit was external. Heat pumps need free airflow on three sides plus a condensate drain run. If your old electric storage was in a cupboard or alcove with restricted airflow, a heat pump may need relocation — adding $400–$900 in pipework changes. Always get the installer to do a site visit before quoting; this is the most common surprise cost on heat pump swaps.
How long does a Wollongong hot water swap take?
Like-for-like electric storage swap: 2–4 hours. Like-for-like gas continuous swap: 3–5 hours. Electric-to-heat-pump swap: 5–8 hours (more pipework, electrical work). Gas-to-electric or electric-to-gas swap: 6–10 hours (requires gas decommission certificate or new gas/electrical run). Most jobs complete same day; rarely a unit ships late and forces an overnight delay.
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