Hot water is something we tend to take for granted. We turn on the tap, take a nice hot shower and wash dishes and laundry without giving it a second thought. That is, until there is none! This is why the good old hot water cylinder is actually one of the most important household appliances!

Like any other appliance, water heaters do have a fixed lifespan. In fact, they are especially prone to wear and tear due to their constant exposure to heat and moisture. This means leaks, deterioration, and other functional issues can occur, resulting in dreaded cold showers or even water damage to the home.
So, how do you know if you should repair or replace a hot water cylinder, and what are your options? Let’s take a more in-depth look in to what you need to know about hot water cylinder replacement.

How Do Hot Water Cylinders Work?

Simplicity has always been the key to the success of traditional hot water cylinders. They are the tried and tested workhorse of the household appliances, delivering hot water on demand with minimal fuss. Working on a principle similar to boiling the jug, hot water cylinders use an element-based heating system encased within an insulated and reinforced storage tank. They automatically heat and maintain the water at the desired temperature (regulated by the cylinder thermostat).

During normal operation, cold water automatically enters the cylinder storage tank as hot water exits. This results in the water temperature being reduced at the bottom of the tank, which then triggers the thermostat, allowing the element to activate and heat the water up to the desired temperature again. This process continues 24/7, keeping you in a constant supply of perfectly heated hot water!

7 Signs Your Hot Water Cylinder Needs Replacing

Knowing when to replace your hot water cylinder can save you from the inconvenience of “cold water” surprises and also expensive emergency plumbing repairs. How can you tell if your hot water system needs replacing? Here are the top 7 signs to look out for.

1. Water Discolouration. If your hot water comes out of the tap with a brownish or rusty tint, the interior of your hot water cylinder could be corroded. This is a clear sign that you need to get someone to take a look, as it is only a matter of time before the cylinder starts leaking.
2. Insufficient Hot Water. Have you noticed you seem to run out of hot water more frequently than before? Sometimes, this is an indication of sediment build-up in the bottom of the hot water cylinder. An excessive amount of sediment hinders the operational efficiency of the element at the bottom of the cylinder, reducing its efficiency in maintaining the correct temperature.
3. Leaks. Moisture around the bottom of your cylinder is a big problem – this is likely a result of the breakdown of the hot water cylinder’s internal components or the pipes where water enters and exits the cylinder. Call your plumber immediately if you notice leakage from your cylinder, full replacement is usually the only option here.
4. Fluctuating Water Temperatures. If you notice your hot water switching between hot and cold or find you aren’t able to get the shower hot enough, this can be a sign your hot water cylinder is struggling. There could be an issue with the thermostat or the elements.
5. Odd Noises. While some noises are perfectly normal, if you hear excessive noises (popping, rumbling etc) coming from your hot water cylinder, this can mean it is struggling operationally. The most common causes of a noisy cylinder are hardened sediment and corrosion interacting with the heated water.
6. Water Pressure Problems. While water pressure can be related to a range of plumbing issues, sometimes it can result from sediment build-up in your hot water cylinder. Or, if your home still relies on a low-pressure hot water system, upgrading can be worthwhile for the increase in water pressure alone.
7. Unexpected Power Bills. Have you noticed your electricity bill rising a lot lately without any logical explanation? The older your hot water cylinder, the more likely it is to be less efficient electricity-wise, meaning it take more electricity to heat your water than a modern one.

Should You Repair or Replace Your Water Heater?

When you start encountering problems with your water cylinder, deciding whether to repair or replace it can be confusing. Some quick fixes, such as replacing the thermostat or elements, can extend the life of your cylinder without costly replacements. However, choosing to repair instead of replace could end up costing you money over the longer term. Here are the things to consider when thinking about hot water cylinder repair versus replacement.

• Age. A hot water cylinder’s average life expectancy is 10 to 15 years. If yours is approaching this age or older, a replacement is likely the best option. Cylinders over 15 years old are way more likely to develop leaks and lose energy efficiency.
• Frequent Repairs. If you have had to undertake a lot of cylinder repairs recently, this can be a sign your cylinder is on its last legs. Discuss with your plumber whether full replacement may be a better option.
• Recurring Issues. Some water heater problems are just minor, while others point to serious system failures, understanding the difference can help you decide whether a simple fix will do or if a full replacement is the better choice. Are you having recurring issues with your hot water system? A full replacement might be necessary in order to resolve these ongoing issues. A good rule of thumb is if the cost of repairing your water heater is more than half the price of a new one, getting it replaced is a better option.
• Operational Efficiency. Does your water heater meet the current needs of your household? Sometimes the decision to replace instead of repair can be purely based around operational efficiency. You might just need a bigger cylinder because your family has grown.

How To Choose A New Hot Water System

Ready to upgrade your hot water system? There are a few things to think about when selecting a new hot water heating system for your home. Top of the list is choosing a water heater that will not only provide enough hot water for the entire family when they need it but also one that will do so in an energy-efficient way. Here are five key things to consider when choosing a hot water heating system.

• Running Costs. How much is it going to cost to heat your water every day? Investigate the pros and cons of gas, electricity, solar and heat pump hot water systems.
• Energy Efficiency. Doing some research into the energy and cost savings over the longer term will help you understand how energy-efficient a water heating system is. There are a number of good websites with up-to-date information on energy efficiency ratings and cost savings for various hot water heating systems. The government’s EECA Gen Less website is a good place to start.
• Purchase, Installation And Maintenance Costs. What are the upfront costs to purchase and install the system, and are there any ongoing maintenance requirements?
• Amount Of Hot Water Needed. No one wants to run out of hot water, so double-checking the size requirements based on the number of people in the household is always a good idea. As a general guide, one person on average will use around 40-60 litres of hot water per day.
• Life Span. Source some reliable information regarding the expected lifespan of your selected hot water heating systems, as this can have an impact on value for money. Some systems are less likely to stand the test of time in certain geographical locations or require significantly more maintenance than others.

Hot Water Heating Options In NZ

Now that you know what to take into consideration when choosing a hot water system, it is a good idea to do some research on all of the available water heating options that will suit your circumstances. Below are the common types of water heaters available here in NZ.

Conventional Electric Hot Water Cylinders

This includes both low and high-pressure hot water cylinders that provide a tank full of hot water that is kept at a set temperature all day, most commonly heated by electric elements. These generally tend to be less expensive to install and have fairly long expected lifespans. Some of the more modern ones are able to be installed outside, giving the added benefit of saving space.

On-Demand Water Heaters

Heating water instantly as it flows, there are two general options here: gas or electric continuous flow hot water heating systems. Both are considered very cost-efficient as water is only heated as it is used, and they require very little installation space as no storage tank is needed. People favour these systems as you never run out of hot water.

Heat Pump Hot Water Heaters

Many people have heat pumps installed in their homes for general space heating, but the technology is now used to heat water. The heat pump hot water system focuses on moving heat from one form to another instead of generating heat directly (transferring heat from the air the water). Heat pump hot water systems are reported to be several times more efficient than standard electric water heating systems.

Solar Power Water Heating

Designed to use the sun’s energy to heat hot water, these systems often require a bigger initial outlay but do tend to have the cheapest running costs in the long term. They are becoming a more popular choice as electricity prices rise and the technology becomes more readily available. A backup battery storage system is sometimes required if enough solar energy is not generated during the day.

Wetback Hot Water Heating

Installing a wetback system to your fireplace uses the heat generated by the fire to top up your water heating. Hot water is heated as it passes through pipes in the rear of the fire. Adding a wetback to your fire can be costly and requires a specifically designed hot water cylinder and specially approved types of fires, plus it only works best if your hot water cylinder is situated in close proximity to the fire. Wetback hot water heaters are not considered a standalone water heating option as the system only works when the fire is burning.

At Whitehead Plumbing & Gas, we install, repair, and maintain electric, gas, solar, and heat pump hot water systems. If you’re unsure about the best replacement option for your hot water cylinder, contact us today for expert advice tailored to your home.