The questions people ask us before they buy.
Written by plumbers who fit these every week. No sales pitch — if the cheaper option is the right one for you, that is what it says.
How much does it cost to replace a hot water cylinder in NZ?
Real numbers from the New Zealand market, split into what the cylinder costs and what the installation costs.
Reviewed 2026-09-02What size hot water cylinder do I need?
Sizing by household, and why going one size up is usually cheaper than regretting it.
Reviewed 2026-09-02Heat pump or standard electric cylinder?
What each one costs to buy, what each costs to run, and who should pick which.
Reviewed 2026-09-02What does replacing a hot water cylinder involve?
Why a cylinder has to be connected by a licensed plumber, and what the job actually includes.
Reviewed 2026-09-02The hidden part that changes hot water cylinder prices
Two cylinders can hold the same amount of water and still be very different buys. The price usually comes down to the lining, the warranty conditions, the shape, the casing, and the water you are asking the cylinder to live with.
Reviewed 2026-09-08Low pressure or mains pressure: the first choice you cannot guess
A low pressure cylinder can be rated for 76 kPa while a mains pressure cylinder can be rated for 850 kPa, so this is not a small difference. Before you choose a size or brand, find the data plate and confirm what your house is actually running.
Reviewed 2026-09-08Will your new cylinder fit? Same litres can be 600 mm taller
Cylinder capacity does not tell you the shape. Before you order, check the width, height, service clearance and the path the cylinder has to travel.
Reviewed 2026-09-08Can your hot water cylinder go outside? Check the casing first
Outdoor siting is not decided by whether the tank is stainless steel, copper or enamel. It is decided by the cylinder casing, the pipe run back to the kitchen, and whether the unit can still be serviced properly.
Reviewed 2026-09-08The hot water cylinder warranty trap hiding behind ten years
A ten year cylinder warranty is rarely ten years of everything. Here is what the main New Zealand warranty documents actually say about cylinders, parts, labour, rentals, commercial use and the conditions that can switch cover off.
Reviewed 2026-09-08The Auckland heat pump cylinder running cost most guides get wrong
Most heat pump cylinder running cost guides still use an electricity price around 28 cents. Using MBIE's May 2026 national average of 42.0 c/kWh changes the arithmetic, and it makes the heat pump saving look stronger, not weaker.
Reviewed 2026-09-08180 litre hot water cylinder NZ: prices, dimensions and which to buy
Every 180 litre cylinder we sell compared: price, height, diameter, weight, mains or low pressure, heat-up time and warranty. Rheem MPVE 31218015 and 32218015, Rinnai ME180488E30, Thermann 180L, Rheem MPSS 32518015 and the low pressure options.
Reviewed 2026-10-28How long does a hot water cylinder take to heat up? Times by size and element
Heat-up times worked out for 25 to 300 litre cylinders with 2, 2.4, 3 and 3.6 kW elements, why yours may take longer, and what a heat pump does differently.
Reviewed 2026-10-28How long do hot water cylinders last in NZ?
Cylinder warranties by brand and lining, what we see in Auckland homes, the signs a cylinder is near the end, and what makes one last longer.
Reviewed 2026-10-28Vitreous enamel, copper or stainless steel hot water cylinder: which is better?
How the three cylinder linings differ in warranty, pressure, water limits, anode and price, with the models we sell in each, so you can pick the right one for your water.
Reviewed 2026-10-28Hot water cylinder anode rod: what it does and when to replace it
What a sacrificial anode is, why enamel cylinders need one, magnesium versus aluminium, the rotten egg smell, and the Thermann anode sizes by cylinder.
Reviewed 2026-10-28Why is my hot water cloudy, milky or smelly?
The glass test that tells harmless air bubbles from sediment, what a rotten egg smell means, and when discoloured hot water points to the cylinder.
Reviewed 2026-10-28Hot water cylinder leaking or relief valve dripping: what it means
Where the water is coming from tells you what has failed: a dripping expansion or relief valve, a leaking fitting or element, or the tank itself. What is normal and what needs a plumber.
Reviewed 2026-10-28250 litre hot water cylinder NZ: prices, dimensions and which to buy
Every 250 litre cylinder we sell compared: price, height, diameter, weight, heat-up time, indoor or outdoor, and whether a Haier HP250M1U1 heat pump makes more sense. Thermann 250L, Rinnai ME250590E30 and MS25055030, Rheem MPSS 32525015 and Rinnai LS25055030.
Reviewed 2026-10-28135 litre hot water cylinder NZ: prices, dimensions and which to buy
Every 135 litre cylinder we sell compared: price, height, diameter, weight and heat-up time, including the 935 mm stubby models, low pressure copper and enamel, and the Thermann 160L that fits nearly the same space.
Reviewed 2026-10-28Gas hot water NZ: natural gas or LPG bottles, where it can go, and cost against electric
Natural gas or 45 kg LPG bottles, the clearances that decide where a gas water heater and the bottles can go, and what a year of hot water costs on gas against an electric cylinder and a heat pump. Rinnai Infinity A26, HD56 and Rheem Stellar 160L.
Reviewed 2026-10-28Heat pump hot water cylinder NZ: is it worth it? Cost, power use and which to buy
What a heat pump cylinder costs, how much power it saves for 1 to 2, 3 to 4 and 5 or more people, how many years the extra price takes to come back, and which model fits: Haier HP200M1U1, HP250M1U1, HP330M1U1 and the HP300 split, Rheem AmbiPower, Rinnai HydraHeat and Thermann 270.
Reviewed 2026-10-28Still not sure which one you need?
Send us a photo of the data plate on your existing cylinder. It states the capacity and the pressure rating, which is most of what anyone needs to tell you what replaces it.