Category Archives: Hot Water Talk

How long does a hot water cylinder last NZ?

Hot cylinders have been here for a long time. They’re one of the most common forms of hot water heating system in New Zealand that’s proven to be reliable and cost-effective. Hot water cylinders tend to last for 8 to 15 years, depending on the type and quality of the unit.

However, hot water cylinders still need adequate and regular maintenance despite the expected long life. No matter what kind of water heater you have, if you don’t take care and check its condition regularly, it can spell early doom for your equipment. 

The unfortunate reality is some hot water cylinders last shorter than they should. After five years, some families might have to get rid of their water heaters. On the other hand, others might be lucky enough to keep their units running for 15 years.

Making the time to monitor the status of your cylinder makes the difference between having to buy a new heater right after your warranty runs out and being able to keep it for a few more years.

So, how can you keep your hot water cylinder running for a longer time? Here are some things you can do:

  1. Check the Anode Rod. Anode rod corrosion causes hot water cylinder failure. To prevent this, check its condition regularly, Replacing if necessary.
  2. Remove Limescale. Limescale can cause your water heater to lose efficiency. Flushing your heater with pure white vinegar will remove limescale buildup.
  3. Flush out Sediments. Hot water cylinders need annual flushing to clean out the tank’s bottom sediment.

Of course, if you’re unfamiliar with working with hot water cylinders, you don’t need to force yourself. We always recommend contacting a reputable hot water cylinder specialist like Hot Water Cylinders NZ for any service or repair difficulties. 

Reach us today at 0800 4 CYLINDERS or 0800 429 546.

Checking Water Quality – Its Role in Hot Water Cylinder Maintenance

Hot water cylinders are widely used in the country, especially in residential areas. The system is usually comprised of water pipes connected to a broiler. Heated water travels out from the tank to the kitchen tap, bathroom shower, or any other parts of the house that require water use. Then, as the hot water exits, the tank draws in cold water and heats it again. The cycle repeats every time you use up water. According to Smarter Homes, with proper cylinder maintenance, you will never run out of hot water in your household for about 20 to 40 years. 

Unfortunately, hot water cylinder maintenance is most likely the last thing you think of when you list your usual home maintenance tasks. If you want to ensure your cylinder’s optimum condition, be sure to schedule regular check-ups and maintenance. You can start your routine by testing the water quality. 

You can use chlorine and hard water testing kits to check your home’s water quality. Alternatively, you can call in a plumbing company to have the water checked, and the cylinder inspected for possible damage.

Why Checking the Water Quality Matters

Not too long ago, Stuff published a report on Michael Neilson, a homeowner in Christchurch, who complained about his hot water cylinder failing after adding chlorine to the water. Neilson holds the Christchurch council accountable and demanded them to shoulder the $2167 bill. He is the second person to challenge the board in the last few years after the chlorination of the city’s water supply. Both the plumber and insurer confirmed his claim explaining that the damage indeed resulted from too much chlorine. 

The council has confirmed in earlier reports that the chlorine content of Christchurch’s water is indeed high. And yet, they still haven’t paid for the bill of Mr. Neilson. 

It is an upsetting situation, but it’s also the perfect example to emphasize the importance of checking water quality. If chlorine or other chemicals in the water exceed normal levels, it could result in a disaster similar to Neilson’s water heater problem.

How to Test Water Quality and What to Do When the Quality is Poor

If your water contains excessive amounts of chlorine, it could corrode the cylinder. In a typical setting, stainless steel doesn’t rust. But, if it’s exposed to chemicals such as chlorine, the passive layer of the metal slowly breaks down. The best way to get around the issue is to use chlorine treatment and filters. Also, if you move to an area with high water’s chlorine level, it may be worth it to invest in a copper cylinder.

On one hand, if the problem is caused by high levels of minerals like magnesium and calcium, your cylinder may suffer from pitting corrosion. The excess calcium or magnesium binds to free-floating chlorine. The process produces calcium chloride or magnesium chloride, which can attack both stainless steel and copper cylinders’ molecules. If you detect high levels of such minerals, you can use a water softener or schedule regular cylinder flushing.   

With regular maintenance checks, it would be easier for you to spot potential problems. This way, you get to use basic solutions and prevent damages to your hot water cylinder. If you suspect damage on your cylinder due to high chlorine, calcium, or magnesium, it’s highly recommended to have it checked right away. 

Call for Help When Needed

Oftentimes, it’s intimidating to do maintenance checks for usual home equipment like hot water cylinders. It can be challenging for some to spot the first signs of problems. Fortunately, there are a lot of professionals who can help you with plumbing works and water heater-related concerns. All you need is to call their attention and book an appointment. If you have problems with your heater, don’t hesitate to call for help.

Flexible Sacrificial Anodes: The Future of Water Heating Technology

Would you spend 449 including GST to increase your hot water cylinders lifespan by 10 years?

Of course! 

Imagine living in a place filled with a light cool breeze during the day, and freezing temperatures during the night. Turning on the faucets and having warm or hot water for baths, showers, washing, and whatnots is a complete comfort – the epitome and pinnacle of rest and relaxation.

In New Zealand, this isn’t an uncommon occurrence. For a country far from the sun’s rays on the equator New Zealand is definitely a cool place, abundant of rainfall and glaciers. Temperatures in New Zealand go from 10 degrees centigrade down south, and 16 degrees centigrade up north. Throughout the year, temperatures change ever so slightly!

A specific type of tank-type water heater is the Hot Water Cylinder, that uses supply water pressure and delivers hot water to showers and taps. As this type of system does not use a cold-water storage tank, it is designed for small spaces and sometimes limited access. Hot Water Cylinders are enclosed with safety mechanisms that include relief valves, thermostats, and somtimes expansion vessels.

Why You Need A Sacrificial Anode

The problem with this type of heating system is that it does not last very long at the constant pressure and heat changes it faces. That is where a sacrificial anode comes to place. This replaceable component helps maintain and control the rate of corrosion there is in the tank and is present in every water heating system. Sacrificial anodes are often made out of magnesium and attracts all corrosive elements to prevent metal breakdown.

In the span of 10 years, these anodes become very corrosive and will degrade, contributing to the damage of the heating system itself. What many people don’t know is that this anode can easily be replaced, expanding its life to over 20 years, and getting the bang out of your buck.

It should be noted that only steel hot water storage needs a sacrificial anode. It becomes a secondary type of protection to the steel in any hot water tank. Because anode rods are created using less sturdy metals than steel, the node fends off attack from minerals and other materials in your water. This is why anodes are called sacrificial.

Another thing that many people don’t know is that sacrificial anodes must be replaced every 5 years to get over 20 years of use from the hot water cylinder! The real problem now is replacing the anode in a really small, tight, and cramped place such as the hot water cupboard. Replacing this over 1 meter long component needs wide space and it should not be removed or disconnected in the cylinder, which is terribly a huge cost.

Why Use the Flexible Sacrificial Anode?

This is where the Flexible Sacrificial Anode comes into light! This type of sacrificial anode eliminates several other challenges when it comes to replacing the anode. There will no longer be a need to drain and remove the cylinders, and you will no longer have to put a hole above your ceiling for access!

This anode needs less than 250 millimeters of clearance and is very time efficient as it can be installed in an hour. Upgrading your sacrificial anode to a flexible sacrificial anode is the best choice to make, because expanding the life span if your hot water cylinder outweighs the costs of buying a new one every few years.

Where to Buy Flexible Sacrificial Anodes

Buying flexible hot water cylinder sacrificial anodes are no longer a hassle in the country. Companies like Rheem, a New Zealand staple since 1958, sell products that are at the leading edge of hot water heating technology that benefits not only residential areas, but also the commercialized areas of the country.

Hot Water Cylinders NZ invests in innovation and technology to improve your experience with hot water systems here in New Zealand. Our latest innovation allows you to replace your existing Anode without having to dismantle your whole water cylinder installation. Becuase conventional Rods are very long it is almost impossible to replace without disconnecting the entire cylinder and its pipework enabling this physically.  A flexible anode makes this possible and avoids these costs. Without much hassle our technicians will remove the degraded Rod and easily replace is with a flexible model keeping the hot water cylinder in its place which provides the same protection at a much lower installation cost.

Learn more about how to upgrade your sacrificial anode when replacing a hot water cylinder here.

Cowboys Install Fake Hot Water Cylinder

Two elderly ladies were just asking for the removal of their hot water tank and replacing it with a tankless hot water heater when a father and son team abused the trust of their customer by conning them into putting in a fake water heater.

Michael Lucosh, 66 and his son who also goes by the name of Michael, 27 was hired to install a tankless water heater. But instead, they gave their poor victims a fake hot water cylinder. Adding insult to injury, the younger Lucosh stole checks and a debit card from their victim’s purse. Meanwhile, his father was responsible for forging the signatures and then cashing the checks, as well.


Source Article

They have been the ones to install the original hot water tank and had broken that trust from their customer by doing this senseless act.  Aside from stealing, the fake water heater was not installed properly and could become a fire hazard.  Fortunately, they have been caught by the police and are now facing charges.

How to Pick the Best Water Heater Installer Company

When picking the best installer for your needs, there are several things to look for so that you will be given the best service. One of these qualities is Professionalism.  The installer should be reliable, professional and should take his job seriously otherwise, what you will receive is a below-average service.

They should be able to reassure their clients that they can get things done the soonest possible time. And, at the same time, they should be able to provide excellent service from the start of the job up to the finish line.

Another quality that one should look for is expertise.  Even if you are not an expert on water heating installation, you will be able to know whether a technician really knows what he is talking about and then follow it through with exceptional work. This should also not just be about installing or replacing a water heater but also, they should be able to point out which part is having issues and then how to address it.

Experience is also a factor.  Hiring a company that has long-standing reputation of excellent service should also be considered.  You must first check the background of the company the technician has worked for whether they have great reviews and has been recommended by a number of people.

The experience should not be just based on the company but this should also include the experience of the technician.  They should have several references and come highly recommended too.

Another thing to take into consideration is efficiency.  The job should not stretch for a long time and if you have any concerns or questions, they should be able to provide you with a clear answer.  Jobs should be accomplished within the promised time.

Most importantly, without this, none of the aforementioned qualities is useful.  There should be trust. Trust with the company and trust with the installer.  You have to make background checks with regards to the legitimacy of the company and that they should have the proper permits and licenses.

Aside from potential clients doing background checks with the company, the company itself should conduct a thorough background check with their installers.  They should check that the references that they have provided are legitimate and that the job that they have rendered is up to the highest standards.  Not only will the investigation focus on skills, this will also include that their staff have a clear record especially since they will be working inside the homes of families.

Warning Signs

There should be warning signs that you should not ignore when you are hiring someone to do a job for you.  Some of them are as follows:

  • Too good to be true – When what goes through your mind is to question whether an offer is too good to be true, most likely it is not. Reputable companies may not be the cheapest but sometimes the cheapest ones aren’t always the best ones.  As they say, you get what you paid for. If an installer is offering you their services at a very low estimate compared to the average, this should raise the red flag.  Are they going to provide you with sub-par materials? Do their installers actually have the skills and the experience? Do you really think that they are there to provide you with an honest service?
  • Trust your emotions and Gut instinct – If you feel that there is something wrong in the picture, trust your instincts and explore further. It is always better to be over prepared, over informed than none at all.  If you don’t find anything wrong then at least take comfort in the fact that you have all your boxes ticked.
  • Time-pressure – If a company or technician rushes you to make hasty decisions then there is a high possibility that you will go the wrong way. Decision-making should not be done in a flash; you have to weigh your options, check further and listen to your gut before signing the dotted line.
  • When they won’t take “No” for an answer – A good service provider should be able to listen and understand the client’s needs and concerns, if they don’t have this then they are in the wrong field of business. As a client, if your service provider does not listen to you, then they may not be the one for you.  They should have an open mind to understand your concerns and be able to address it accordingly.

Hot Water Cylinder New Zealand has done numerous installations across the country already and because of this experience, we have developed a high level of competency that our competitors are finding it difficult in offering the same quality of service.  To keep their reputation glowing, we make sure that our team are licensed and can take care of our client’s needs from beginning to end.  We employ our own staff therefore we do not need to subcontract with others.  Thus we can reassure our customers that they can put their trust in us.

How Do I Know If My LPG Bottle Is Empty?

A shower running cold mid-bath is never a welcome change. And it’s just as frustrating when your heating appliance or gas hob stops without a hint, because you’re suddenly out of gas. You can stop this annoying thing from happening again if you know when your LPG bottle is running low.

Help is here as we’ll show you an easy way to check when the bottle is about to run empty – so you can keep your gas supply going.

How long does a LPG bottle last?
For a family of two adults and two children, a 45kg bottle used for both hot water and gas cooktops will typically last about 6-8 weeks. It’s a different thing if you add a gas-fired space heater.

Gas cylinders typically have a change-over regulator (reg) installed between them. Some cylinders have an automatic reg that switches from the empty bottle to the full one when the first runs out. Other cylinders have a manual regulator, which you will need to turn by hand to switch to the reserve bottle.

The change-over regulator usually has a viewing window or an indicator. When both bottles are full, the indicator will be Black, Green or Clear. When one bottle is empty, the indicator will be RED. The reg will have a change-over valve and a directional arrow. If your regulator is manual, do not adjust the directional arrow. Many people mistake it for the change-over valve, but the arrow simply indicates which bottle is empty.

It’s a good idea to regularly check the indicator on the change-over regulator, so you can call us when one bottle is empty.

How to test the level of LPG in the cylinder
One way is to pour warm (not boiling) water down the side of the bottle. Wait a few minutes, then run your hand down the side of the bottle. The level where it feels cool to the touch indicates how much LPG is left.

This is a fairly accurate method, but there’s an easier and faster way – using a LPG cylinder weighscale.

gas_bottle_scaleThis is an innovative sensing device that monitors bottled gas levels and automatically sends an accurate reading of the remaining gas in the cylinder. The weighscale is installed underneath your LPG cylinders. We can set them up for you, and once they’re there, checking your cylinders will be one less thing to worry about.

The device is also tied to a mobile app, which you can  access to get detailed daily usage reports or prompts when your cylinders need a refill. You never need to guess the gas level as there are easy to view visuals and graphs for the remaining LPG. As the supplier, we also have this data in the app, so we’ll also know when to deliver the next cylinder so you can keep your gas going without interruptions.

This works for both residential and commercial applications. For more information about this new technology, a chat or call is most welcome. Get in touch with Hot Water Cylinders NZ!

Gas Hot Water Vs Electric

The Hayman Thermostatic Storage Electric Heater made by L.T Hayman Ltd in Auckland you see is almost 60 years old!

gas_VS_electric_water_heatingIncorporated is a Satchwell Thermostat (made in South Africa) enabling the user to change the internal storage temperature. This was before our new laws around Legionnaires’ disease were passed a few years ago preventing manufacturers from incorporating an adjustable thermostat.

As in the case of our Hayman Thermostatic Storage Electric Heater, when an older tank gives up and it’s time replace it, the question each home owner should ask is, “Is it worth switching to gas?”.

To read up on some of the benefits when upgrading to gas, please visit our Upgrade to Gas section.

old_low_pressure_hwcThis blog is not designed to convince you to buy a gas product, rather point out the benefits gas will bring and, in some instances, the disadvantages when upgrading from an electric hot water cylinder.

When looking at gas vs electric water heating there are several things you will want to ask yourself, including why, when, and how much will it cost?

The following should play into your decision making:
Why do I want an upgrade to gas?
Is it Opportunity, because your cylinder needs replacing?
Is it Savings, because you believe gas is cheaper to run?
Is it Lifestyle, because want to enjoy unlimited time in the shower?

Whatever the reason may be, it’s important to know all the facts.

Without doubt, the best time for an upgrade to gas is when your hot water cylinder needs to be replaced. This is simply because you are about to spend $1500+ on a replacement which could go towards a gas water heating system if all variables apply.

If you have done your due diligence and are confident gas is the way to go, then by all means upgrade to instant gas water heating.

To help with your due diligence, we have compiled the following “to do list” for you.
If you can answer all the below with Yes, then you are ready to go with gas!

  1. Are you upgrading because your hot water cylinder needs to be replaced?
  2. Do you have a single level home?
  3. Are you upgrading from low pressure to gas?
  4. Can the gas unit be positioned in a compliant manner and central to most delivery points, especially the kitchen and shower?
  5. Do you already have gas on the property or intend to go with LPG at the time of upgrade?

If you are looking at gas because you believe it’s cheaper to run, then you are right and you are wrong. Savings will fully depend on your site conditions and how your current hot water cylinder system is set up.

There are ways to make savings on an electric system without upgrading to gas including:
• Flow restrictors
• Smart controllers
• Better insulation

If your home has 2 levels or more, you may want to be cautious before upgrading to gas as pipe lag and undersized units may result in more energy use, negating any desired savings. Additionally, in many cases when upgrading from mains pressure to gas you will also experience a water pressure drop. Pressure loss with instantaneous water heating systems is very common, especially when retrofitted into the existing house plumbing.

Lifestyle is one of those reasons that is hardly arguable. The home owner understands the pros and cons and is willing to make sacrifices to gain a specific desired outcome.
Some of these include:
• Longer showers
• Gas cooking
• Combination systems

Despite your motive, it is advisable to keep all the above points in mind.
Whether you are upgrading to gas or upgrading to mains pressure, one of the key factors is your property.

Before making any commitment, get a second or even third opinion. Why not speak to the hot water specialists to get advice on a solution that will not only compliment your property and desired benefits but also meet your budget!
Call Hot Water Cylinders NZ today!

Hot Water Storage Cylinders, The Facts

Simply put, a hot water storage cylinder is a tank used to store hot water required for space heating or household use. It goes by other names such as hot water tank, heat storage tank, hot water cylinder, thermal storage tank or hot water thermal storage unit.

We don’t often think about this appliance as long as we get hot water on demand. But as soon as we’re greeted with that unwelcome cold shower, the realisation hits. The good news is hot water tanks are generally reliable and operate for many years without a glitch.

When that hitch finally comes, it’s good to have a background on this household convenience. It will also reduce your energy spending. Here are all the information you need to know when choosing the right hot water cylinder.

hot_water_storage_cylinder_mains_pressureTypes of storage cylinders

The main type of new installations in New Zealand are mains pressure storage water heaters, where the operating pressure is the same as the incoming supply (120-1,400 kPa, usually 350-700 kPa).

Besides that, other heaters operate as:

  • Low pressure, open-vented system, wherein pressure is provided by a cold water storage header tank (3-12 m head/30-120 kPa). This was traditionally used in Kiwi homes.
  • Low pressure system with a pressure-reducing valve to minimise the mains pressure water (3-12m head/30-120 kPa)

Here’s how the three types of systems compare:

Heater Type Mechanism Pros Cons
Low pressure, open-vented, header tank Cold water stored in a header tank is fed via gravity into the storage water tank located below the header tank. As the water is heated, it rises to the top of the cylinder where it can be drawn for domestic use.

The heating process causes water expansion, hence the open-vent pipe for releasing excess pressure. This pipe typically feeds back into the header tank supply.

  • Cheaper to install
  • Few valves required
  • Equal pressure system
  • Quiet operation
  • Suitable for wet back connection
  • Needs wider pipes
  • Needs grading to avoid air locking
  • Low pressure supply
  • Prone to pressure fluctuations
Low pressure, pressure reducing valve system

(open-vented or unvented)

This type works similar to a header tank system, but it uses a pressure-reducing valve to reduce the pressure from the mains supply to a pressure that can be maintained within the height of the vent pipe.

Supplies low pressure hot water and high pressure cold water to fixtures, hence called unequal pressure system.

  • Inexpensive installation and maintenance
  • Few valves required
  • Suitable for wet back connection (if open-vented)
  • Difficult to achieve a balanced flow to a shower
  • Needs larger diameter pipework for hot water supply
  • Prone to pressure fluctuations
Mains pressure, unvented Supplies mains pressure hot water to all outlets. It has an expansion vessel (internal or external) that allows the heated water to expand, but a pressure relief valve is recommended in case of expansion vessel failure.

This valve must be specified for the particular system used to achieve the required pressure rating.

  • More flexibility in locating the cylinder as header tanks and vent pipes are not required.
  • Equal pressure system
  • High pressure hot water
  • Quick hot water delivery
  • Smaller diameter pipework
  • Greater flexibility of pipework


  • More water wastage due to frequent heat-up cycles
  • Increased depreciation on pipes and fittings
  • Difficult to install
  • Subject to water hammer


Hot water storage tanks can also be classified based on how they are run: electric or fuel fired. The most commonly used fuel is gas, either natural or propane. But in some areas, an oil-fired heater is popular.

Fuel-fried models have vent pipe at the top that carry off exhaust gases, while electric units simply have a power cable connecting the heater to your electric service panel.

Indirect vs. Direct systems

This refers to how the water is heated in the tank. Most cylinders are indirect systems. They are heated using an external source such as a solar thermal or gas boiler, where water is heated then fed through a copper coil in the hot water tank. The heat is then transferred from the external heat source to the water inside the cylinder. In direct systems, an internal immersion heater directly heats the water inside the tank.

Methods for storing heat

  Method Advantage
Hot water tank with closed water circuit Heat is stored in the tank using external heat exchangers (coils) that can be directly tapped or used to power other heat exchangers The tank is not continually fed with cold water, which reduces limescale deposits especially in ‘hard’ water areas

Reduced oxygen levels, which minimises requirements for materials used in the tank, water circuits and pipework

Stratified hot water tank with closed circuit/ stratified thermal storage/ thermocline tank/ water stratified tank storage Mechanisms are put into place to maintain the vertical stratification of the water column, i.e. water at the top must be kept hot (90-95oC) and water at the bottom cold (20-40oC). Best for places with wide climatic range.

Design and construction

Water heater tanks are usually made of stainless steel, copper or vitreous (porcelain) enamel-lined carbon steel.

Electric and gas types are mostly similar in construction, sharing common components such as the drain valve, TPR valve, dip tube, internal anode rod and pipes and fittings. The main difference is that electric water heaters have a separate thermostat, while gas water heaters have a built-in gas control valve. In addition, gas models have an internal flue to vent gas and circulate heat; a heat limiting device to prevent overheating; and a special sensor called a ‘thermocouple’ to shut off the gas in case of emergency.

Most modern hot water tanks are made of stainless steel, which is lined with glass to prevent corrosion. Corrosion or rusting is the main reason for tank failure. An anode rod inside the tank also prevents the steel from rusting. It corrodes in place of the steel, so this part must be checked once a year and replaced if necessary. Otherwise, the steel will start to rust. Once a hole forms, the tank will eventually have to be replaced.

At the bottom of the tank is a drain cock that will empty the heater. A valve is fitted on the supply pipe to shut down the hot-water plumbing without interrupting the cold-water supply.

Because hot water tanks both heat and store water, they need to have some sort of insulation in order to maintain warm water in between heating cycles.


Water has a high specific heat capacity, which means it can store more heat per unit of weight compared to other substances. It’s one of the best medium for heat storage. In comparison, it can store four to five times as much heat as stone and up to ten times as much as most metals, per unit of weight.

When kept in an efficiently insulated tank, hot water will retain heat for longer. Thermal insulation significantly reduces standby heat loss and speeds up the heating process, which means you use less energy for heating water.

The most common insulating material for hot water tanks is fibreglass, which is typically fixed in place with straps, tape or the outer jacket of the water heater. For outdoor tanks, sprayed-on polyurethane insulation is common.

Water heaters have different insulation ratings. If you find the rating too low, you can add extra insulation on the outside of the tank to further reduce heat loss. In places with extreme weather conditions, the hot water cylinder can be fully enclosed in a specially built insulated space.

However, there is such thing as “too much” insulation. If you live in humid locations and you add more layers of insulation to an already well-insulated tank, condensation may occur which may lead to rust, mould or other operational problems. Air flow or combustion gas outflow, either by convection or fan-assisted, must be maintained to prevent condensation.

Heater effectiveness

Both the recovery rate and capacity of the tank affect your supply of hot water at home.

The recovery rate, or the speed at which a tank heats water, indicates how many gallons of water can be heated to 100oF in an hour. When you’re using water faster than it’s heated, you’ll eventually get colder water from the tap. However, since the tank also stores hot water, its capacity will also affect the ongoing supply at the tap.

Choosing a hot water tank with a suitable capacity and recovery rate depends on your household’s hot water demands. Electric heaters typically have low recovery rate but high tank capacity, which makes them suitable for intermittent use. On the other hand, fuel-fired tanks heat water faster but don’t necessarily have a large cylinder, which is good if you need hot water ready any time of day.


As mentioned earlier, tank capacity is a major consideration in choosing a hot water cylinder. Choosing a cylinder that’s too big will unnecessarily bump up your energy bill, while a tank too small will mean bouts of hot water shortage.

The right size depends on how much hot water your household uses on average. If you’re not sure, the table below will give you an idea on which size you need:

Family Size Gas Electric
1-2 30 30
2-3 40 40
3-4 40 50
5 or more 50 80

For big households or for commercial use, a tank with a higher recovery rate and capacity is ideal to ensure uninterrupted supply of hot water.

Space requirements

f can be installed in interior spaces of a property or in auxiliary areas such as a basement, garage or crawlspace. Ideally, they should be located closest to the plumbing system. Pipes running from the tank must be installed vertically for faster delivery of hot water into the home. The pipework may be adjusted when installing a hot water cylinder in less than ideal locations.

If standard-size water heaters do not suit any of the available spaces in your property, you have two other options to choose from.

Tall tanks (also called tall boys) range from 46 to 60 inches in height and 18 to 21 inches in diameter, and are typically installed in basements or garages where the height can be accommodated easily. They can hold up to Extra height is required to allow the connecting pipe to be installed on top of the tank.

Short tanks (also called low boys) range from 30 to 49 inches in height and 20 to 26 inches in diameter, and are suitable for crawlspaces, under cabinets or areas with low headroom. These are shorter and wider than the standard water tank, allowing them to hold the same amount of water (up to 50 gallons).

If you’re looking at hybrid water heaters, you’ll need extra space for proper installation. So that’s one thing to consider.

Safety issues

Water stored below 60oC can permit the growth of harmful bacteria, such as those that cause Legionnaire’s disease which is fatal to young children and those with compromised immune systems. This is why some jurisdictions impose a limit on tank water temperature. However, water at a temperature above 49oC can cause painful scalding injuries.

In order to prevent both dangers, it is recommended to use mixing valves that would automatically mix cold water with the hot water from the tank to maintain maximum temperature below 49oC. These valves are installed at outlets for sinks, showers or baths.

Features and Modern Technology

  • ENERGY STAR rating

Modern appliances are given star ratings to indicate their energy efficiency. The ENERGY STAR is a government-backed symbol that can help you choose and support energy efficient products and practices. Check the energy factor (EF) rating as well – it speaks of a product’s water-heating efficiency.

Products with higher ratings are more efficient. While they are typically more expensive upfront, they are designed to save you money in the long run. Not to mention, they have a smaller carbon footprint.

For easy comparison, check the EnergyGuide labels of the units you’re considering. This will give you an idea on how the product is expected to perform and how much its estimated annual operating cost.

  • Smart water heaters

Modern water heaters have intuitive technology that “learns” your household’s hot water consumption patterns and automatically adjusts the temperature and other operating features accordingly. These are obviously more energy efficient, which can reduce your energy bill.

Installing a hot water cylinder

Installation is best done by a qualified professional. An experienced plumber would know well how to run pipes or where to locate the tank, and would give helpful advice in choosing a suitable hot water cylinder for your home.

Google Googled Hot Water Cylinders And Found The Right Specialist

Founder Larry Page’s luxury yacht Senses is sitting in Auckland needing two new specialized hot water cylinders. So the Google founder’s maintenance company Googles “hot water cylinder specialist” and finds Hot Water Cylinders NZ.

They found the ultimate hot water cylinder specialist right there and then, because his maintenance company went ahead and signed us up for the job. Seeing our expertise and capability, they have trusted HWC NZ to replace the existing units and manufacture the exact same models to get their superyacht ready for sail once again.


The cylinders were designed with the following specifications:

  • 250L horizontal marine style duplex stainless steel hot water cylinder
  • S/S 304 cased & insulated
  • 550dai x 1525 length
  • 3 x custom element flanges to suit existing stock elements
  • 850KPA relief valve and 20mm connection
  • Custom inlet & outlet sizes based on original
  • 20mm cylinder drain
  • No coil
  • 1x tank anode
  • Mounting angle brackets including nuts and bolts


Check out a video of these marine hot water cylinders below:

Marine Hot Water Cylinders

Designed to withstand the special demands of the marine vessels and boats, our marine hot water cylinders are built with the highest quality components to ensure optimal performance and longevity.

Our marine cylinders are made with grade 304 stainless steel, which has good resistance to oxidation even in continuous service in temperatures of up to 925oC. And when you’re out in the water 24/7, corrosion resistance is a crucial factor. In comparison to other materials used in hot water cylinders such as copper-nickel or aluminium-bronze alloys, stainless steel resists salt-water corrosion better which makes it a clear choice for marine hot water cylinders.

That being said, stainless steel is not totally immune to corrosion. It can experience localized corrosion under certain conditions, so some stainless steel cylinders will fare better than others. The difference lies in engineering and design. Needless to say, our team is confident that we can supply cylinders fit for a supercraft like Senses.

The new cylinders had to be the same design because other pre-made units would neither perform well enough for the superyacht’s hot water demands nor sit well with its Philippe Starck interior.

Google trusts its search engine to show the best and most reliable experts in their fields, so much so that they chose Hot Water Cylinders NZ when it showed on the top results.

Gaining the trust of one of Google’s executives says a lot about our team. These people mean business in whatever they do. And we know they only make strategic decisions that will provide the best outcome for them. Senses is a yacht for VIPs, celebrities and the affluent who expect nothing short of luxury, so everything in it must be built to impress.

We don’t take the word “specialists” lightly. We brand ourselves that way because we know our job extremely well. We don’t just sell the priciest cylinders in order to drive sales, we take the time to listen to our clients’ needs and specifications in order to provide the best in terms of performance, efficiency and economy. Whether it’s gas, electric or solar powered, we’ve got the expertise and experience for that!

In the case of Senses, our goal was to build reliable hot water cylinders at par with the standards and specifications of the original. That’s a huge feat, considering we need to design and supply everything from the custom element flanges to the nuts and bolts.

More about Senses

Photo credit:

Photo credit:

The 59.2 metre expedition motor yacht was engineered by Germany’s Fr. Schweers Shipyard in 1999 and was last refitted in 2015. Built to surpass the challenges of the world’s oceans, Senses is Lloyds rated and deemed perfect for the 21st century adventurer. describes Senses as “the opportunity for a truly unique lifestyle in luxury yachting” with its stylish interiors and comprehensive inventory of equipment. True enough, the yacht features an impressive arsenal of toys including six WaveRunners, two jet skis, kitesurfs, surfboards, kayaks, paddle boards, a Jetboard, a Jetlev and a helipad – plus tons of inflatable toys for endless parties!

The yacht offers lavish accommodations for up to 12 guests, with 7 spacious modern cabins and a gymnasium that can also be converted into a cabin.

Hot Water Demand on Boats

With its 15,000 km plus of coast, waterways and lakes, New Zealand is every boatie’s paradise. Boating is like a way of life, a tradition during perfect summer days for families and solo adventurers alike. Living on boats is also a growing trend amongst Kiwis who love boating and want something other than the typical lifestyle.

Whether you’re sailing for the weekend or you’re on an extended cruise with lots of water adventures in between, you can never have enough of hot water on board. A nice warm shower is the ultimate refresher, washing off the salt and sweat at the end of the day. Especially when you’re wintering someplace on a boat, hot water is something you just can’t live without.

Many boats carry a water heater that operates either from engine heat or on electricity. The problem with the former is that the engine has to be running constantly to ensure a steady supply of hot water. That’s very inefficient when you’re just mooring, and causes unnecessary wear on the engine. The fact that the water in the heater can be heated depending on the temperature of the engine’s coolant creates some serious safety risks. Nevertheless, these heaters work well for smaller boats.

For bigger vessels, a custom-fitted hot water cylinder makes a lot more sense, due to its larger capacity and efficiency.

In the case of Senses which has a private beach club complete with a Jacuzzi, sauna and steam room, having hot water on demand is essential. Now with its new high spec hot water cylinders, Senses is once again ready for charter in New Zealand and the South Pacific.

With the right type and size of hot water cylinder, you can enjoy these creature comforts and luxuries in your own boat, too!

Talk to us for a consultation on any of these numbers: 0800 4 CYLINDERS or (NZ FREE) 0800 429 546.

The District Health Board Is Warning People Against Turning Down Their Hot Water Cylinders To Save Money

Legionnaires’ disease, also called Legionellosis, is a severe and potentially fatal type of pneumonia. It is contracted by inhaling water vapour or steam containing the Legionella bacteria, which is very likely to happen when taking a hot shower.

The bacteria love warm, stagnant water. They can grow in water temperatures ranging 20 – 45oC and thrive in the range of 32 – 44oC, which commonly occur in plumbing systems, spa pools, hot water tanks and evaporative condensers of commercial AC systems. However, Legionella bacteria cannot grow at higher temperatures and are killed almost instantaneously at around 70oC.

legionnaires_disease_in_hot_water_cylindersThis is why the District Health Board is sending a warning against turning down hot water cylinders in an attempt to save money. For the same reason, the Building Code also requires hot water systems to have the storage water heater thermostat set to a minimum of 60oC.

This warning should not be taken lightly. Legionnaires’ disease can lead to respiratory failure, septic shock or complications that may result to organ failure or even amputation, which was sadly the case for two people in Hawke’s Bay in 2015.

Facts about Legionellosis

  • The illness is caused by Legionella strains, particularly pneumophila and L. longbeachae, which are ubiquitous in the New Zealand environment. They are found in both potable and non-potable water systems, and can easily find their way into engineered water reticulation systems.
  • Hot water cylinders are a breeding ground for the Legionella bacteria, as are boiler systems, water-cooling towers, garden hose-pipes, air conditioners and even mist sprayers in the grocery store produce section. Legionella can also survive in some soils or composts.
  • Legionella bacteria cannot be contracted by drinking contaminated water nor transmitted from one person to another.
  • In healthy people, the disease manifests as a very bad cold with symptoms including high fever, chills, headaches, muscle aches, loss of appetite, cough and occasionally diarrhoea. But for those with immature or impaired immune systems (i.e. children, older people, smokers, alcoholics, cancer patients, etc.), the effects can be much worse and fatal.
  • A mild form of Legionnaires’ disease, known as Pontiac fever, doesn’t affect the lungs and usually clears within two to five days without treatment.
  • Although the bacteria primarily target the lungs, it can also cause infections in wounds and other parts of the body.
  • Some infected people will suffer long-term health issues such as fatigue, neuromuscular and neurologic symptoms.
  • The legionella bacteria primarily spread through micro water droplets, but it can also be transmitted via aspiration of contaminated water or working with contaminated soil.

Are you safe from Legionellosis?

Homes and workplaces are generally safe. But as a homeowner, it is your duty to undertake regular maintenance of your water systems. Workplaces are also required under legislation to comply with building maintenance guidelines, especially those with cooling towers.

Many infections are without symptoms as healthy adults have antibodies to the bacteria, showing evidence of previous exposure. Only a small number of cases will have had an illness with symptoms.

What can you do to minimize your risk?

Prevention should always be the first course of action.

  1. Since Legionella bacteria cannot survive in water at 60oC or above, you should keep your hot water cylinder at a minimum temperature of 60o
  2. For households with a roof collected tank water supply or other non-reticulated water supply, the water tank must be maintained according to the guidelines.
  3. When working with potting mix, soil or compost, wear a mask to avoid inhaling dust. Dampen the soil to avoid stirring up the dust too much.
  4. Installing tempering/mixing valves are recommended to ensure safe water temperature at the tap. To prevent burns and scalds, water tap temperature should be no more than 45oC for children and no more than 55oC for adults.

For more information about keeping your water systems safe, contact our team at 0800 429 546.

Chlorine Can Damage Your Hot Water Cylinder

The sudden spike in hot water cylinder failure in Christchurch is said to be connected to the recent introduction of chlorine to the local water supply, according to this report. The controversial chemical is believed to have led to leaks in pipes and cylinders. Since the issue broke, more than 2000 hot water cylinders have been replaced.

Property management firms and cylinder manufacturers have reported an increase in plumbing faults and demand for new units.


Chlorination and Corrosion

New Zealand has had many years of chlorine-free water supply until recently when a deadly gastro outbreak due to water contamination happened in Havelock North. Many people argue that chlorine may not be to blame as some parts of the country with chlorinated water did not experience the same problem. So is the Christchurch dilemma an isolated case?

It turns out that Christchurch isn’t the only one. Last year, plumbers in Hastings reported a 30 per cent spike in hot water cylinder breakdown following the chlorination of the local water supply, according to a New Zealand Herald report. The same thing happened to Hastings and Napier as well.

So does chlorinated water actually cause corrosion?

Chlorination may not be directly to blame. However, the presence of chlorine in the water supply is a major contributing factor. Older cylinders may have existing cracks or pin holes, which are usually plugged up by mineral and lime scale that has built up. When chlorine is added to the water, it cleans and dissolves the sediments in the cylinder, exposing the cracks or pinholes. This explains why a hot water cylinder which has been working fine in the last 3 decades is suddenly failing.

That bChlorine_can_damage_your_hot_water_cylinder_2eing said, some cylinders that have only been running for 18 months also failed. Many units in the area were newly replaced in the aftermath of the quake. So many pointed out that chlorine may also strip off the protective oxide coating from the copper, making the cylinder more prone to corrosion and leaks.

Experts analysed a number of defective cylinders in Christchurch and found multiple corrosion pits, which they concluded to be the cause of the unit failure. Traces of chlorine were identified in all pitting sites but were not present on non-pitting surfaces, which proves that chlorinated water actually causes a chemical reaction in the pipes.

Causes of Corrosion

Copper is nearly a noble metal due to its reluctance to oxidation or corrosion. Copper in hot water cylinders also has an added layer of oxide lining that makes it practically “rust proof”.

causes_of_corrosion_hot_water_cylinderHowever, copper may actually corrode when there is galvanic action or electron movement between the copper and its surroundings. Here are several other factors that can contribute to the corrosion of pipes, fittings and fixtures. The degradation of a cylinder depends on the rate at which one or more of these factors work:

  • Chemicals – Water carries naturally occurring and added minerals and impurities which can effect corrosion in various ways. For instance, high levels of calcium (which often present in hard water) may lead to calcification in pipes and fittings. When the water is chlorinated, the chemical compounds in the added chemical can react with copper, steel and plastic pipes which will consequently accelerate the corrosive action of both plastic and metal plumbing fixtures.
  • PH levels – Copper has an oxide lining that could be stripped when the water is at a certain PH level. This leads to a more rapid rate of corrosion.
  • Oxygen – Both water and oxygen are required for rusting to occur.
  • Temperature – Chlorine in extremely hot water is particularly corrosive on copper, brass, galvanized iron and stainless steel pipes and fittings. While this fact is taken into consideration when designing hot water cylinders, corrosion is inevitable and will happen gradually.

causes_of_corrosion_hot_water_cylinder_2Oxidation can happen uniformly or non-uniformly. Uniform surface corrosion is usually caused by low PH or high PH and when the copper comes into contact with phosphates or air. This gives the copper a greenish patina. Non-uniform corrosion drills pits into the surface. If the pitting is severe enough, it can penetrate a pipe and cause pinhole leaks.

Preventive checks

For cylinders to fail in less than 10 years is unacceptable, especially since replacement can cost a bomb and a lot of trouble.  Preventing corrosion can be more challenging when the water is mass treated. But the good news is you can pre-empt future failures and extend the life of your hot water cylinder. Here’s what you can do:

  • Watch out for moisture. It’s easy to overlook a slight drip, but you’ll know it’s there when the carpet is getting a bit wet or moist.
  • Keep an eye out for discoloured water or the appearance of blue-green stains in sinks and baths. If there’s white buildup around the fittings, that’s already a sign of calcification.
  • Have your cylinder checked according to maintenance schedule to find any pitting and stop potential leaks in their track.
  • If you are installing a new unit or a replacement, check with your installer that the cylinder is fit for purpose and has proper galvanic protection. We recommend replacing alloy-coated cylinders with Titanium-coated ones, because Titanium is more resistant to corrosion.
  • Make sure to choose a reliable installer with a good record, as correct installation has a major effect on the performance and life of your cylinder.
  • Make sure the sacrificial anode is in good condition. To find out more about sacrificial anodes click here.

When it happens, corrosion won’t be your sole problem. The water damage caused by leaks can impact your flooring, cabinetry and building structure as well. So it’s imperative that the unit and pipework are checked and maintained as needed.

For more information, contact our team today on 0800 429 546.