The hot water cylinder warranty trap hiding behind ten years

Rheem publish at least three different warranty tables all numbered SWH186 Rev E, and the numbers are not all the same.

The shared revision letter is not a typo. The December 2021, February 2024 and November 2025 documents carry the same revision letter, but the figures changed. On Stellar gas, for example, cylinder labour moved from five years to three. If another listing, quote or old saved PDF gives a different answer, the person may not be trying to mislead you. They may simply be reading a document that still looks current. With Rheem, check the date at the foot of the page, not just the revision.

This matters because the phrase ten year warranty is doing a lot of work. The phrase almost never means ten years of the cylinder, ten years of parts and ten years of labour. A hot water cylinder warranty is usually split into three separate pieces: the cylinder or tank itself, the other parts, and the labour allowed for replacing the cylinder during the covered period.

If your cylinder has just failed, that distinction can feel like fine print at the worst possible time. But it is the difference between buying with your eyes open and assuming the headline number covers everything. The distinction also helps you compare cylinders properly, because two products can both say ten years while giving quite different labour cover.

First, what the three warranty parts mean

The cylinder or tank is the big storage vessel that holds the hot water. When a listing says the cylinder has a ten year warranty, the listing is usually talking about this part. Depending on the model, it may be stainless steel, copper, or vitreous enamel lined steel. Vitreous enamel is a glass-like protective lining baked onto the inside of a steel cylinder, a little like the way enamel protects a bathtub.

Other parts are the fittings and components supplied with the cylinder. The exact parts vary by product, but the warranty documents separate them from the tank. They usually have a much shorter term.

Labour is the third piece, and it is the one many homeowners only discover after something goes wrong. Labour cover is not a general promise to pay any plumber for any job at any time. It is the manufacturer warranty labour component attached to the covered failure, and it only exists if the unit was installed by a licensed person. New Zealand law also requires a licensed person for this work. If someone who cannot certify the work connects the cylinder, part of what you thought you had bought may be gone.

Rheem domestic warranty figures, dated 11 November 2025

For Rheem, the figures below are from the domestic warranty table dated 11 November 2025. The order is other parts / cylinder labour / cylinder replacement, all in years.

• Mains pressure vitreous enamel, low pressure vitreous enamel, All Pressure: Domestic 1 / 5 / 10. Non-domestic 1 / 1 / 3.
• Optima: Domestic 3 / 5 / 12. Non-domestic 1 / 1 / 5.
• Mains pressure stainless, indoor and indoor/outdoor: Domestic 1 / 3 / 10. Non-domestic 1 / 1 / 3.
• Low pressure copper: Domestic 1 / 1 / 5. Non-domestic 1 / 1 / 1.
• Stellar gas: Domestic 1 / 3 / 10. Non-domestic 1 / 1 / 5.
• AmbiPower MDc-180 and 280e: Domestic 1 / 3 / 7, sealed system 3. Non-domestic 1 / 1 / 3, sealed 1.

There is one important footnote on the Rheem enamel rows. Cylinders made before 1 June 2018 carry the older, shorter terms. The older, shorter terms may not affect a new purchase, but they matter if you are standing in front of an existing Rheem cylinder and trying to work out what cover it originally had.

Notice how different those numbers feel once they are separated. A Rheem mains pressure vitreous enamel cylinder in a domestic setting has a ten year cylinder replacement term, but the other parts are one year and the cylinder labour is five years. A Rheem mains pressure stainless model has a ten year cylinder term too, but cylinder labour is three years. Both can be described with a ten year headline. They are not identical warranties.

Rinnai warranty figures

Rinnai also separate the cylinder, labour and other parts. Their residential and commercial terms are not the same, and for stainless, copper and low pressure products the differences are significant.

• Rinnai mains pressure enamel: 7 year cylinder, 5 year cylinder labour, 1 year other parts.
• Rinnai mains pressure stainless: 10 year cylinder, 5 year cylinder labour, 1 year other parts. Commercial is 5 year cylinder, 1 year labour, 1 year parts, and Rinnai require the cylinder to be sized to their written guidelines.
• Rinnai low pressure copper: 5 year cylinder, 1 year labour, 1 year parts. Commercial is 1 year on all.
• HJ Cooper low pressure stainless, sold by Rinnai: everything is covered in year one. The inner cylinder is replaced free of charge in years two to ten, but from year six the removal, re-installation and labour are the owner's cost. Commercial is cylinder to 3 years, and labour is the owner's from year two.
• Rinnai HydraHeat heat pump: 7 year cylinder, 5 years on the head unit and other parts, 1 year labour.

The HJ Cooper low pressure stainless warranty is a good example of why the headline number is not enough. The HJ Cooper warranty reaches ten years for the inner cylinder, but that does not mean ten years of the same cover. From year six, the owner pays the removal, re-installation and labour. If you only ask whether it has a ten year warranty, you miss the part that affects the bill later.

Haier warranty figures

Haier's domestic warranty is 7 year inner cylinder and 5 years parts and labour. Commercial is 1 year cylinder and 1 year parts and labour.

Again, the split matters. The inner cylinder term and the parts and labour term are not the same length. If you are comparing Haier with a ten year cylinder product from another brand, compare each part of the warranty, not just the largest number in the row.

A rented house is not automatically commercial

The domestic-or-commercial classification is widely got wrong, and it can make landlords nervous for no reason. Domestic or commercial is decided by the building and its use, not by the tenancy and not by who owns it.

Rheem define domestic as installed in a single family domestic dwelling. Rinnai define residential as serving a single family dwelling, not used for commercial purposes, with the thermostat at 70 degrees C or below.

An ordinary rental house is therefore residential. The house does not become commercial just because the people living there pay rent. The cylinder is still serving a household.

Use changes the answer. Rinnai's own examples of a dwelling used commercially are a hair salon, catering kitchen and communal care facility. A salon operating in the front room is not the same warranty situation as a normal rental. One cylinder serving several dwellings is commercial. Rinnai also explicitly treat a motel as residential where the cylinder serves the equivalent of a single family dwelling.

The simple kitchen-table version is this: ask what the cylinder is serving. One normal household is residential. A business use, several dwellings, or a set-up outside the manufacturer's residential definition can push it into the commercial column. If you are a landlord with a standard house, the residential column is usually the one you should be reading.

Water chemistry can void the cylinder warranty

Hot water cylinders care about the water inside them. Concern about water chemistry sounds odd until you think of the cylinder as a metal container that is heated, cooled and refilled thousands of times. If the water is outside the limits published by the manufacturer, it can attack the cylinder, the lining or the fittings in ways the warranty will not cover.

Both Rheem and Rinnai publish water chemistry limits, and water outside those limits voids the cylinder warranty. Rheem state that testing is at the owner's cost.

We cover water chemistry, linings and why some cylinders suit some supplies better than others in the price guide at /guides/why-cylinder-prices-differ. The short version for warranty purposes is this: if you are on bore water, rural supply, aggressive water, unusually hard water, or anything you already know is not standard town supply, check before buying. The right cylinder is partly a warranty decision, not just a price decision.

Installation must be done by a licensed person

The labour component only exists if a licensed person installed the cylinder. Having this work done outside the proper licensing requirements is also illegal in New Zealand.

The licensing requirement is not a small paperwork point. If a cylinder is bought online and then connected by someone who cannot certify the work, the owner may have lost the labour part of the warranty before the first shower. Keep the installation paperwork with the purchase invoice. Years later, when a claim depends on dates and proof, that folder or email trail is worth more than memory.

Hot Water Sorted supplies cylinders only. We do not include installation labour pricing here, because installation is site-specific and must be handled by the licensed person doing the work.

Location can affect what Rheem will pay

Rheem will not pay warranty costs where the cylinder sits somewhere that forces major dismantling or special equipment to reach a serviceable position.

The access restriction means access is not just a plumber's convenience. Access can affect warranty costs. A cylinder tucked behind fixed joinery, boxed into a ceiling space without practical access, or placed where it cannot be reached without dismantling half the room is a different proposition from one sitting in a normal cupboard with safe working access.

If you are replacing an old cylinder, it is tempting to put the new one exactly where the old one lived. Sometimes that is fine. Sometimes the old location was only acceptable because nobody had to deal with a warranty claim yet. Ask the installer to think about future service access before the cylinder is connected and filled.

A warranty does not cover every loss caused by a leak

Consequential loss is not covered. In plain words, the manufacturer warranty may deal with the failed cylinder, but it does not automatically pay for the damage the leak caused around it.

Rinnai are direct about this. All cylinders must be installed with a drip tray. A drip tray is a mandatory requirement of the installation. Where a leaking cylinder without one damages carpet or flooring, the owner must pursue the installer or claim on insurance. Rinnai's own worked example is a faulty inner cylinder at 11 months. The cylinder is replaced. The damaged flooring is not.

A drip tray is not there to make the cupboard look tidy. The tray exists because water escaping from a cylinder needs somewhere controlled to go. Without it, a small failure can become a flooring, carpet or cabinetry problem very quickly.

Rinnai thermostat settings matter

Rinnai's residential definition includes the thermostat being at 70 degrees C or below. A thermostat above 70 degrees C takes a Rinnai cylinder out of the residential definition.

A thermostat setting is easy to overlook because most homeowners do not think of a thermostat setting as a warranty classification issue. But if the manufacturer has put the temperature into the definition, it matters. If your system needs unusual temperatures for a special reason, check the warranty position before assuming the residential column still applies.

What you need if a claim is ever made

A claim needs proof of purchase and proof that the installation was done by a licensed person. Rinnai also ask owners to register the system.

The thing customers most often lose is the invoice. Keep it. Keep the product paperwork too, but the invoice is the document that proves when and where the cylinder was bought. If you are a landlord, keep it somewhere separate from tenant records so it survives tenancy changes. If you are a homeowner, email a copy to yourself or store it with your insurance documents.

Also keep the installation certificate or invoice from the licensed person who installed it. If a warranty question comes up several years later, the manufacturer will not be standing in your hallway remembering who did the work. The paperwork has to do that job.

How to read a product page without being caught out

Start with the headline cylinder term, but do not stop there. Read the other parts term. Read the cylinder labour term. Then check whether your use is residential or commercial under the manufacturer's wording.

For Rheem, remember that the current domestic table referred to here is dated 11 November 2025, even though older tables may carry the same SWH186 Rev E revision label. For Rinnai, remember that an ordinary rental is residential, but business use in a dwelling can change the answer. For all brands, remember that water chemistry, licensed installation, access, drip tray requirements and proof of purchase are not side issues. They are the conditions that make the warranty work.

On Hot Water Sorted product pages, look for the commercial line as well as the domestic or residential warranty. If your property is not a straightforward single family dwelling, or if one cylinder serves more than one dwelling, check your use case with us before buying rather than after. Choosing the right cylinder now is much easier than arguing about the wrong warranty later.