Wellington Water Heating Experts
Hot water is the job Southern does more than any other — and has done since 1982. Electric cylinder swaps, gas continuous-flow, heat pump water heaters, solar systems. We install them, service them, and stand behind them 24/7.
Same-day replacement if you call before 10am — stock permitting. Cylinders in stock for every major NZ brand. Serving Karori, Johnsonville, Khandallah, Lower Hutt and the Kapiti Coast.
Call 0800 484 353 — 24/7. Your Job On Time, or It’s Free.
Four Types of Hot Water Systems
- Electric cylinder — tank with an element inside. Cheapest capital cost, moderate running cost. Typical lifespan 10–25 years depending on quality.
- Gas continuous-flow (Rinnai Infinity etc.) — heats water on demand, no tank. Endless hot water. Fast-recovery for big households.
- Heat pump water heater — highest capital cost, lowest running cost. Great COP (~4) in Wellington’s climate. Needs an outdoor unit.
- Solar hot water — rooftop collectors feeding a cylinder. Best paired with electric boost for winter.
7 Things to Know Before Replacing Your Cylinder
- Size — too small and you run out in winter, too big and you’re heating water you won’t use.
- Element size — drives recovery time. Bigger element = faster reheat.
- Electrical — who’s connecting it? We usually do it so there’s no second trade to book.
- Valves — don’t reuse 15-year-old valves on a new cylinder. Replace them together.
- Tank quality — 5-year vs 10-year warranties behave very differently in reality. Cheap tanks often barely make the warranty.
- Resale value — a cheap tank looks cheap at sale time.
- Pressure upgrade — going from low to high pressure? Increase capacity, because high pressure uses more hot water.
Gas Water Heating vs Heat Pump — Which Wins?
The honest answer: gas wins on capital cost, heat pumps win on long-term running cost.
Gas continuous-flow is $4,500–$6,000 installed. Running cost ~17c/kWh equivalent. Lasts 10–15 years, familiar technology, easy servicing.
Heat pump water heater is $9,000–$12,000 installed. Running cost ~7c/kWh equivalent (assuming COP of 4 — not all units hit that, some do better, some worse). The fridge-style compressor adds maintenance complexity down the line, but operating cost is roughly 40% of gas.
Over 15 years of use, a heat pump comfortably pays back — if you expect to stay in the house. If you’re selling in 2 years, gas is usually the better call.
Smart Tanks, Mains Pressure Upgrades
Smart tanks learn when you use hot water and only heat it just before you need it — cutting standby heat loss. Good for households with predictable routines, less so for shift workers.
Upgrading to mains pressure gives you modern shower performance and opens up contemporary tapware choices. You’ll use more hot water, so we usually recommend a capacity bump at the same time. See our shower pressure page for a breakdown.
External installations? See our external cylinder guide. Tight spaces? Underbench and remote-sink options available.
No Hot Water? Here’s Where to Look
Electric cylinders — common causes: faulty element, failed thermostat, blown fuse, tripped ripple-control at the meter board, or a stuck tempering valve. Do not open any electrical covers — 240V inside.
Gas systems — pilot out, gas supply issue, flat batteries in older Bosch units, or a tripped surge protector in an electronic unit. On continuous-flow: power off and back on often resets electronic faults.
If your hot water is off entirely, call 0800 484 353. We usually diagnose over the phone first and bring the right parts. 24/7 dispatch across Wellington, Hutt Valley and Kapiti.
Frequently Asked Questions
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Rough guide: 135L for a 1-2 person household, 180L for 3, 250L for 4-5, 300L+ for large families. Upgrading from low to mains pressure? Go up a size — mains pressure uses more water per shower.
