A new hot water cylinder in NZ typically costs $2,000 to $4,500 installed, according to Call A Tradie NZ, 2026. Gas continuous flow and heat pump systems cost more upfront, and the right choice depends on your household size and power price.
Prices below are from installers and cost guides, so treat them as a guide for checking a quote. They are not a fixed price for your job.
The quick answer
| Job | Typical NZ price | Source |
|---|---|---|
| Hot water cylinder replacement, installed | $2,000 to $4,500 (rates exclude GST unless stated) | Call A Tradie NZ, 2026 |
| Electric storage cylinder, like-for-like (Auckland) | $2,499 to $3,500 (GST not stated) | Water & Gas Worx, 2026 |
| Gas continuous flow, installed (Auckland) | $3,599 to $5,500 (GST not stated) | Water & Gas Worx, 2026 |
| Heat pump hot water system, installed | Around $7,000 | Consumer NZ, 2024 |
| 180 litre low pressure to mains pressure upgrade (Auckland and Waikato, offer dated 2022) | $2,190 including GST | HotWaterCylinders.NZ, updated 2022 |
| Gas mains pressure 160 litre, replacing an old gas unit (Auckland, offer dated 2022) | $4,250 including GST | HotWaterCylinders.NZ, updated 2022 |
Auckland installer pages are the main source for system-by-system prices, so prices in other regions may differ. The HotWaterCylinders.NZ page was last updated in December 2022, so its prices will be lower than today’s.
What changes the price
The system type. An electric storage cylinder is the cheapest to install. Water & Gas Worx says gas continuous flow is not a direct swap, because it needs gas, water, flue and electrical work. A heat pump costs the most upfront.
Low pressure or mains pressure. Moving from a low pressure cylinder to mains pressure costs more than a like-for-like swap, and may expose weaknesses in existing pipework. Sustain Trust notes the same for heat pump conversions. HotWaterCylinders.NZ says upgrading valves on one offer cost an extra $525, and a solar or heat pump ready mains cylinder costs $300 more than a like-for-like replacement (GST not stated for either).
Size. Water & Gas Worx suggests a storage cylinder suits a household of 1 to 3 people, and continuous flow suits larger households that keep running out. Heat pump units are larger. Sustain Trust lists Rinnai models at 275 or 340 litres and Daikin at 250 or 315 litres.
Position and access. Moving the cylinder, for example from inside to outside, can mean extra pipework and slower bath heating, says Sustain Trust.
Gas work. Water & Gas Worx says continuous flow also needs a gas compliance certificate.
Running costs
Hot water is about 30 to 40 percent of a household power bill, and a heat pump typically cuts that cost by 60 to 75 percent. Both figures are from Sustain Trust, quoting EECA. The page is undated but cites February 2026 power prices. It also says a family of four spends about $480 a year to run a heat pump at the Wellington average of 36 cents per kWh, and that is roughly 3.5 times cheaper than a standard electric cylinder.
The calculate.co.nz worked example, reviewed 9 November 2026, assumes three people, 3.5 kWh each per day and 28 cents per kWh. It gives about $1,073 a year for a standard electric cylinder and about $358 for a heat pump cylinder.
Consumer NZ disagrees on how big the gain is. In June 2024 it said the cheaper running costs would only save about $56 a year over an electric cylinder, and that a standard cylinder may be the simpler choice at current prices. Households that use a lot of hot water stand to save the most.
A worked example
Using the figures above, take a household of three that is replacing an electric cylinder.
- Running cost gap from calculate.co.nz: $1,073 minus $358 = $715 a year.
- Extra upfront cost of a heat pump: $7,000 minus $3,500 = $3,500, or $7,000 minus $2,499 = $4,501.
- Payback: $3,500 divided by $715 is about 4.9 years. $4,501 divided by $715 is about 6.3 years.
On Consumer NZ’s $56 a year saving, the payback would be far longer. The result swings with your household and your power price, so run your own numbers. The Gen Less water heating tool is the place to do it.
Rules, licences and consents
Licensing. The Plumbers, Gasfitters and Drainlayers Board says DIY plumbing is limited to jobs like fitting a dishwasher or washing machine or replacing taps. Work on water supply pipes is not allowed for DIY. Gas appliance work needs a gasfitter. A plumber’s licence does not automatically cover gasfitting. Ask to see the practising licence, check the expiry date and check the number on the public register. After gasfitting work, a certifying gasfitter must issue a signed certificate within 20 working days of connection. Keep it for selling and insurance.
Building consent. Most straight swaps don’t need one, as long as an authorised plumber does the work. The MBIE exemptions guidance (sixth edition, version 2, January 2026) says exemption 38 covers replacing, or moving, any water heater whose heat sources are all controlled (electric, gas and heat pump units are; the water can’t go above 90 degrees). It does not apply when a heat source is not controlled, such as a wetback on a wood burner or a solar thermosiphon. For those, exemption 37 covers swapping an open-vented cylinder for a comparable open-vented one in the same position on the same pipework; changing to a valve-vented (mains pressure) cylinder, or moving it, needs a consent. MBIE’s heat pump water heater page (updated 1 November 2024) says a new or additional heat pump water heater needs a consent, but replacing an existing storage water heater with a heat pump unit does not when a certifying plumber does or supervises it. If you are unsure, ask your council before work starts.
Signs it needs replacing
Water & Gas Worx (published February 2026) lists these:
- Hot water runs out faster than it used to, with no change in household size.
- Brown or rusty water from the hot taps.
- Water pooling or dampness around the base.
- The cylinder is more than 15 years old.
- Power bills keep rising with no other clear cause.
The same company says most NZ cylinders last 10 to 15 years. A small fault such as a valve is often repairable, so ask the plumber whether the leak is from a part or from the tank.
Questions to ask before you say yes
- Is the price fixed, and does it include GST?
- What is the cylinder brand, size and warranty?
- Does the price include removing the old cylinder, a new tray and drain, and seismic restraints?
- Is the plumber licensed, and for which classes of work? What is their licence number?
- Will you need a building consent, and who applies for it?
- If it is a gas job, will a certifying gasfitter issue the certificate?
- Is the new cylinder mains or low pressure, and are the valves and pipework included?
How GoodTradie helps
GoodTradie is a free service for homeowners. You type the job in, we call you, find one local tradie, and check their licence on the PGDB register before booking them in. We also check the quote against published NZ cost figures like the ones on this page. The price check is a guide, not a guarantee. Type your hot water job in the box at the top of the page to get started.
Sources
- Call A Tradie NZ, how much tradies charge, 2026
- Water & Gas Worx, hot water cylinder vs continuous flow, 2026
- Water & Gas Worx, 5 signs your cylinder needs replacing, 2026
- HotWaterCylinders.NZ, how much to replace a hot water cylinder, updated 2022
- Sustain Trust, hot water heat pumps (quoting EECA), 2026
- Consumer NZ, electrifying your home, June 2024
- calculate.co.nz, hot water cost calculator, reviewed November 2026
- PGDB, advice for consumers
- MBIE, Building work that does not require a building consent, sixth edition v2, January 2026
- building.govt.nz, exemption 4.5, replacement of a water heater connected to a controlled heat source
- building.govt.nz, heat pump water heaters
- Gen Less, water heating systems tool
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