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 2026-09-08Still 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.